From 495ffc4777522e40941753e3b1b79c02f84b25b4 Mon Sep 17 00:00:00 2001
From: Grafting Rayman <156515434+GraftingRayman@users.noreply.github.com>
Date: Fri, 17 Jan 2025 11:00:30 +0000
Subject: Add files via upload

---
 r_basicsr/models/__init__.py                  |  29 ++
 r_basicsr/models/base_model.py                | 380 ++++++++++++++++++++++++++
 r_basicsr/models/edvr_model.py                |  62 +++++
 r_basicsr/models/esrgan_model.py              |  83 ++++++
 r_basicsr/models/hifacegan_model.py           | 288 +++++++++++++++++++
 r_basicsr/models/lr_scheduler.py              |  96 +++++++
 r_basicsr/models/realesrgan_model.py          | 267 ++++++++++++++++++
 r_basicsr/models/realesrnet_model.py          | 189 +++++++++++++
 r_basicsr/models/sr_model.py                  | 231 ++++++++++++++++
 r_basicsr/models/srgan_model.py               | 149 ++++++++++
 r_basicsr/models/stylegan2_model.py           | 283 +++++++++++++++++++
 r_basicsr/models/swinir_model.py              |  33 +++
 r_basicsr/models/video_base_model.py          | 160 +++++++++++
 r_basicsr/models/video_gan_model.py           |  17 ++
 r_basicsr/models/video_recurrent_gan_model.py | 180 ++++++++++++
 r_basicsr/models/video_recurrent_model.py     | 197 +++++++++++++
 16 files changed, 2644 insertions(+)
 create mode 100644 r_basicsr/models/__init__.py
 create mode 100644 r_basicsr/models/base_model.py
 create mode 100644 r_basicsr/models/edvr_model.py
 create mode 100644 r_basicsr/models/esrgan_model.py
 create mode 100644 r_basicsr/models/hifacegan_model.py
 create mode 100644 r_basicsr/models/lr_scheduler.py
 create mode 100644 r_basicsr/models/realesrgan_model.py
 create mode 100644 r_basicsr/models/realesrnet_model.py
 create mode 100644 r_basicsr/models/sr_model.py
 create mode 100644 r_basicsr/models/srgan_model.py
 create mode 100644 r_basicsr/models/stylegan2_model.py
 create mode 100644 r_basicsr/models/swinir_model.py
 create mode 100644 r_basicsr/models/video_base_model.py
 create mode 100644 r_basicsr/models/video_gan_model.py
 create mode 100644 r_basicsr/models/video_recurrent_gan_model.py
 create mode 100644 r_basicsr/models/video_recurrent_model.py

(limited to 'r_basicsr/models')

diff --git a/r_basicsr/models/__init__.py b/r_basicsr/models/__init__.py
new file mode 100644
index 0000000..b01cdba
--- /dev/null
+++ b/r_basicsr/models/__init__.py
@@ -0,0 +1,29 @@
+import importlib
+from copy import deepcopy
+from os import path as osp
+
+from r_basicsr.utils import get_root_logger, scandir
+from r_basicsr.utils.registry import MODEL_REGISTRY
+
+__all__ = ['build_model']
+
+# automatically scan and import model modules for registry
+# scan all the files under the 'models' folder and collect files ending with '_model.py'
+model_folder = osp.dirname(osp.abspath(__file__))
+model_filenames = [osp.splitext(osp.basename(v))[0] for v in scandir(model_folder) if v.endswith('_model.py')]
+# import all the model modules
+_model_modules = [importlib.import_module(f'r_basicsr.models.{file_name}') for file_name in model_filenames]
+
+
+def build_model(opt):
+    """Build model from options.
+
+    Args:
+        opt (dict): Configuration. It must contain:
+            model_type (str): Model type.
+    """
+    opt = deepcopy(opt)
+    model = MODEL_REGISTRY.get(opt['model_type'])(opt)
+    logger = get_root_logger()
+    logger.info(f'Model [{model.__class__.__name__}] is created.')
+    return model
diff --git a/r_basicsr/models/base_model.py b/r_basicsr/models/base_model.py
new file mode 100644
index 0000000..bd2faad
--- /dev/null
+++ b/r_basicsr/models/base_model.py
@@ -0,0 +1,380 @@
+import os
+import time
+import torch
+from collections import OrderedDict
+from copy import deepcopy
+from torch.nn.parallel import DataParallel, DistributedDataParallel
+
+from r_basicsr.models import lr_scheduler as lr_scheduler
+from r_basicsr.utils import get_root_logger
+from r_basicsr.utils.dist_util import master_only
+
+
+class BaseModel():
+    """Base model."""
+
+    def __init__(self, opt):
+        self.opt = opt
+        self.device = torch.device('cuda' if opt['num_gpu'] != 0 else 'cpu')
+        self.is_train = opt['is_train']
+        self.schedulers = []
+        self.optimizers = []
+
+    def feed_data(self, data):
+        pass
+
+    def optimize_parameters(self):
+        pass
+
+    def get_current_visuals(self):
+        pass
+
+    def save(self, epoch, current_iter):
+        """Save networks and training state."""
+        pass
+
+    def validation(self, dataloader, current_iter, tb_logger, save_img=False):
+        """Validation function.
+
+        Args:
+            dataloader (torch.utils.data.DataLoader): Validation dataloader.
+            current_iter (int): Current iteration.
+            tb_logger (tensorboard logger): Tensorboard logger.
+            save_img (bool): Whether to save images. Default: False.
+        """
+        if self.opt['dist']:
+            self.dist_validation(dataloader, current_iter, tb_logger, save_img)
+        else:
+            self.nondist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def _initialize_best_metric_results(self, dataset_name):
+        """Initialize the best metric results dict for recording the best metric value and iteration."""
+        if hasattr(self, 'best_metric_results') and dataset_name in self.best_metric_results:
+            return
+        elif not hasattr(self, 'best_metric_results'):
+            self.best_metric_results = dict()
+
+        # add a dataset record
+        record = dict()
+        for metric, content in self.opt['val']['metrics'].items():
+            better = content.get('better', 'higher')
+            init_val = float('-inf') if better == 'higher' else float('inf')
+            record[metric] = dict(better=better, val=init_val, iter=-1)
+        self.best_metric_results[dataset_name] = record
+
+    def _update_best_metric_result(self, dataset_name, metric, val, current_iter):
+        if self.best_metric_results[dataset_name][metric]['better'] == 'higher':
+            if val >= self.best_metric_results[dataset_name][metric]['val']:
+                self.best_metric_results[dataset_name][metric]['val'] = val
+                self.best_metric_results[dataset_name][metric]['iter'] = current_iter
+        else:
+            if val <= self.best_metric_results[dataset_name][metric]['val']:
+                self.best_metric_results[dataset_name][metric]['val'] = val
+                self.best_metric_results[dataset_name][metric]['iter'] = current_iter
+
+    def model_ema(self, decay=0.999):
+        net_g = self.get_bare_model(self.net_g)
+
+        net_g_params = dict(net_g.named_parameters())
+        net_g_ema_params = dict(self.net_g_ema.named_parameters())
+
+        for k in net_g_ema_params.keys():
+            net_g_ema_params[k].data.mul_(decay).add_(net_g_params[k].data, alpha=1 - decay)
+
+    def get_current_log(self):
+        return self.log_dict
+
+    def model_to_device(self, net):
+        """Model to device. It also warps models with DistributedDataParallel
+        or DataParallel.
+
+        Args:
+            net (nn.Module)
+        """
+        net = net.to(self.device)
+        if self.opt['dist']:
+            find_unused_parameters = self.opt.get('find_unused_parameters', False)
+            net = DistributedDataParallel(
+                net, device_ids=[torch.cuda.current_device()], find_unused_parameters=find_unused_parameters)
+        elif self.opt['num_gpu'] > 1:
+            net = DataParallel(net)
+        return net
+
+    def get_optimizer(self, optim_type, params, lr, **kwargs):
+        if optim_type == 'Adam':
+            optimizer = torch.optim.Adam(params, lr, **kwargs)
+        else:
+            raise NotImplementedError(f'optimizer {optim_type} is not supperted yet.')
+        return optimizer
+
+    def setup_schedulers(self):
+        """Set up schedulers."""
+        train_opt = self.opt['train']
+        scheduler_type = train_opt['scheduler'].pop('type')
+        if scheduler_type in ['MultiStepLR', 'MultiStepRestartLR']:
+            for optimizer in self.optimizers:
+                self.schedulers.append(lr_scheduler.MultiStepRestartLR(optimizer, **train_opt['scheduler']))
+        elif scheduler_type == 'CosineAnnealingRestartLR':
+            for optimizer in self.optimizers:
+                self.schedulers.append(lr_scheduler.CosineAnnealingRestartLR(optimizer, **train_opt['scheduler']))
+        else:
+            raise NotImplementedError(f'Scheduler {scheduler_type} is not implemented yet.')
+
+    def get_bare_model(self, net):
+        """Get bare model, especially under wrapping with
+        DistributedDataParallel or DataParallel.
+        """
+        if isinstance(net, (DataParallel, DistributedDataParallel)):
+            net = net.module
+        return net
+
+    @master_only
+    def print_network(self, net):
+        """Print the str and parameter number of a network.
+
+        Args:
+            net (nn.Module)
+        """
+        if isinstance(net, (DataParallel, DistributedDataParallel)):
+            net_cls_str = f'{net.__class__.__name__} - {net.module.__class__.__name__}'
+        else:
+            net_cls_str = f'{net.__class__.__name__}'
+
+        net = self.get_bare_model(net)
+        net_str = str(net)
+        net_params = sum(map(lambda x: x.numel(), net.parameters()))
+
+        logger = get_root_logger()
+        logger.info(f'Network: {net_cls_str}, with parameters: {net_params:,d}')
+        logger.info(net_str)
+
+    def _set_lr(self, lr_groups_l):
+        """Set learning rate for warm-up.
+
+        Args:
+            lr_groups_l (list): List for lr_groups, each for an optimizer.
+        """
+        for optimizer, lr_groups in zip(self.optimizers, lr_groups_l):
+            for param_group, lr in zip(optimizer.param_groups, lr_groups):
+                param_group['lr'] = lr
+
+    def _get_init_lr(self):
+        """Get the initial lr, which is set by the scheduler.
+        """
+        init_lr_groups_l = []
+        for optimizer in self.optimizers:
+            init_lr_groups_l.append([v['initial_lr'] for v in optimizer.param_groups])
+        return init_lr_groups_l
+
+    def update_learning_rate(self, current_iter, warmup_iter=-1):
+        """Update learning rate.
+
+        Args:
+            current_iter (int): Current iteration.
+            warmup_iter (int)： Warm-up iter numbers. -1 for no warm-up.
+                Default： -1.
+        """
+        if current_iter > 1:
+            for scheduler in self.schedulers:
+                scheduler.step()
+        # set up warm-up learning rate
+        if current_iter < warmup_iter:
+            # get initial lr for each group
+            init_lr_g_l = self._get_init_lr()
+            # modify warming-up learning rates
+            # currently only support linearly warm up
+            warm_up_lr_l = []
+            for init_lr_g in init_lr_g_l:
+                warm_up_lr_l.append([v / warmup_iter * current_iter for v in init_lr_g])
+            # set learning rate
+            self._set_lr(warm_up_lr_l)
+
+    def get_current_learning_rate(self):
+        return [param_group['lr'] for param_group in self.optimizers[0].param_groups]
+
+    @master_only
+    def save_network(self, net, net_label, current_iter, param_key='params'):
+        """Save networks.
+
+        Args:
+            net (nn.Module | list[nn.Module]): Network(s) to be saved.
+            net_label (str): Network label.
+            current_iter (int): Current iter number.
+            param_key (str | list[str]): The parameter key(s) to save network.
+                Default: 'params'.
+        """
+        if current_iter == -1:
+            current_iter = 'latest'
+        save_filename = f'{net_label}_{current_iter}.pth'
+        save_path = os.path.join(self.opt['path']['models'], save_filename)
+
+        net = net if isinstance(net, list) else [net]
+        param_key = param_key if isinstance(param_key, list) else [param_key]
+        assert len(net) == len(param_key), 'The lengths of net and param_key should be the same.'
+
+        save_dict = {}
+        for net_, param_key_ in zip(net, param_key):
+            net_ = self.get_bare_model(net_)
+            state_dict = net_.state_dict()
+            for key, param in state_dict.items():
+                if key.startswith('module.'):  # remove unnecessary 'module.'
+                    key = key[7:]
+                state_dict[key] = param.cpu()
+            save_dict[param_key_] = state_dict
+
+        # avoid occasional writing errors
+        retry = 3
+        while retry > 0:
+            try:
+                torch.save(save_dict, save_path)
+            except Exception as e:
+                logger = get_root_logger()
+                logger.warning(f'Save model error: {e}, remaining retry times: {retry - 1}')
+                time.sleep(1)
+            else:
+                break
+            finally:
+                retry -= 1
+        if retry == 0:
+            logger.warning(f'Still cannot save {save_path}. Just ignore it.')
+            # raise IOError(f'Cannot save {save_path}.')
+
+    def _print_different_keys_loading(self, crt_net, load_net, strict=True):
+        """Print keys with different name or different size when loading models.
+
+        1. Print keys with different names.
+        2. If strict=False, print the same key but with different tensor size.
+            It also ignore these keys with different sizes (not load).
+
+        Args:
+            crt_net (torch model): Current network.
+            load_net (dict): Loaded network.
+            strict (bool): Whether strictly loaded. Default: True.
+        """
+        crt_net = self.get_bare_model(crt_net)
+        crt_net = crt_net.state_dict()
+        crt_net_keys = set(crt_net.keys())
+        load_net_keys = set(load_net.keys())
+
+        logger = get_root_logger()
+        if crt_net_keys != load_net_keys:
+            logger.warning('Current net - loaded net:')
+            for v in sorted(list(crt_net_keys - load_net_keys)):
+                logger.warning(f'  {v}')
+            logger.warning('Loaded net - current net:')
+            for v in sorted(list(load_net_keys - crt_net_keys)):
+                logger.warning(f'  {v}')
+
+        # check the size for the same keys
+        if not strict:
+            common_keys = crt_net_keys & load_net_keys
+            for k in common_keys:
+                if crt_net[k].size() != load_net[k].size():
+                    logger.warning(f'Size different, ignore [{k}]: crt_net: '
+                                   f'{crt_net[k].shape}; load_net: {load_net[k].shape}')
+                    load_net[k + '.ignore'] = load_net.pop(k)
+
+    def load_network(self, net, load_path, strict=True, param_key='params'):
+        """Load network.
+
+        Args:
+            load_path (str): The path of networks to be loaded.
+            net (nn.Module): Network.
+            strict (bool): Whether strictly loaded.
+            param_key (str): The parameter key of loaded network. If set to
+                None, use the root 'path'.
+                Default: 'params'.
+        """
+        logger = get_root_logger()
+        net = self.get_bare_model(net)
+        load_net = torch.load(load_path, map_location=lambda storage, loc: storage)
+        if param_key is not None:
+            if param_key not in load_net and 'params' in load_net:
+                param_key = 'params'
+                logger.info('Loading: params_ema does not exist, use params.')
+            load_net = load_net[param_key]
+        logger.info(f'Loading {net.__class__.__name__} model from {load_path}, with param key: [{param_key}].')
+        # remove unnecessary 'module.'
+        for k, v in deepcopy(load_net).items():
+            if k.startswith('module.'):
+                load_net[k[7:]] = v
+                load_net.pop(k)
+        self._print_different_keys_loading(net, load_net, strict)
+        net.load_state_dict(load_net, strict=strict)
+
+    @master_only
+    def save_training_state(self, epoch, current_iter):
+        """Save training states during training, which will be used for
+        resuming.
+
+        Args:
+            epoch (int): Current epoch.
+            current_iter (int): Current iteration.
+        """
+        if current_iter != -1:
+            state = {'epoch': epoch, 'iter': current_iter, 'optimizers': [], 'schedulers': []}
+            for o in self.optimizers:
+                state['optimizers'].append(o.state_dict())
+            for s in self.schedulers:
+                state['schedulers'].append(s.state_dict())
+            save_filename = f'{current_iter}.state'
+            save_path = os.path.join(self.opt['path']['training_states'], save_filename)
+
+            # avoid occasional writing errors
+            retry = 3
+            while retry > 0:
+                try:
+                    torch.save(state, save_path)
+                except Exception as e:
+                    logger = get_root_logger()
+                    logger.warning(f'Save training state error: {e}, remaining retry times: {retry - 1}')
+                    time.sleep(1)
+                else:
+                    break
+                finally:
+                    retry -= 1
+            if retry == 0:
+                logger.warning(f'Still cannot save {save_path}. Just ignore it.')
+                # raise IOError(f'Cannot save {save_path}.')
+
+    def resume_training(self, resume_state):
+        """Reload the optimizers and schedulers for resumed training.
+
+        Args:
+            resume_state (dict): Resume state.
+        """
+        resume_optimizers = resume_state['optimizers']
+        resume_schedulers = resume_state['schedulers']
+        assert len(resume_optimizers) == len(self.optimizers), 'Wrong lengths of optimizers'
+        assert len(resume_schedulers) == len(self.schedulers), 'Wrong lengths of schedulers'
+        for i, o in enumerate(resume_optimizers):
+            self.optimizers[i].load_state_dict(o)
+        for i, s in enumerate(resume_schedulers):
+            self.schedulers[i].load_state_dict(s)
+
+    def reduce_loss_dict(self, loss_dict):
+        """reduce loss dict.
+
+        In distributed training, it averages the losses among different GPUs .
+
+        Args:
+            loss_dict (OrderedDict): Loss dict.
+        """
+        with torch.no_grad():
+            if self.opt['dist']:
+                keys = []
+                losses = []
+                for name, value in loss_dict.items():
+                    keys.append(name)
+                    losses.append(value)
+                losses = torch.stack(losses, 0)
+                torch.distributed.reduce(losses, dst=0)
+                if self.opt['rank'] == 0:
+                    losses /= self.opt['world_size']
+                loss_dict = {key: loss for key, loss in zip(keys, losses)}
+
+            log_dict = OrderedDict()
+            for name, value in loss_dict.items():
+                log_dict[name] = value.mean().item()
+
+            return log_dict
diff --git a/r_basicsr/models/edvr_model.py b/r_basicsr/models/edvr_model.py
new file mode 100644
index 0000000..1475033
--- /dev/null
+++ b/r_basicsr/models/edvr_model.py
@@ -0,0 +1,62 @@
+from r_basicsr.utils import get_root_logger
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .video_base_model import VideoBaseModel
+
+
+@MODEL_REGISTRY.register()
+class EDVRModel(VideoBaseModel):
+    """EDVR Model.
+
+    Paper: EDVR: Video Restoration with Enhanced Deformable Convolutional Networks.  # noqa: E501
+    """
+
+    def __init__(self, opt):
+        super(EDVRModel, self).__init__(opt)
+        if self.is_train:
+            self.train_tsa_iter = opt['train'].get('tsa_iter')
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        dcn_lr_mul = train_opt.get('dcn_lr_mul', 1)
+        logger = get_root_logger()
+        logger.info(f'Multiple the learning rate for dcn with {dcn_lr_mul}.')
+        if dcn_lr_mul == 1:
+            optim_params = self.net_g.parameters()
+        else:  # separate dcn params and normal params for different lr
+            normal_params = []
+            dcn_params = []
+            for name, param in self.net_g.named_parameters():
+                if 'dcn' in name:
+                    dcn_params.append(param)
+                else:
+                    normal_params.append(param)
+            optim_params = [
+                {  # add normal params first
+                    'params': normal_params,
+                    'lr': train_opt['optim_g']['lr']
+                },
+                {
+                    'params': dcn_params,
+                    'lr': train_opt['optim_g']['lr'] * dcn_lr_mul
+                },
+            ]
+
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+
+    def optimize_parameters(self, current_iter):
+        if self.train_tsa_iter:
+            if current_iter == 1:
+                logger = get_root_logger()
+                logger.info(f'Only train TSA module for {self.train_tsa_iter} iters.')
+                for name, param in self.net_g.named_parameters():
+                    if 'fusion' not in name:
+                        param.requires_grad = False
+            elif current_iter == self.train_tsa_iter:
+                logger = get_root_logger()
+                logger.warning('Train all the parameters.')
+                for param in self.net_g.parameters():
+                    param.requires_grad = True
+
+        super(EDVRModel, self).optimize_parameters(current_iter)
diff --git a/r_basicsr/models/esrgan_model.py b/r_basicsr/models/esrgan_model.py
new file mode 100644
index 0000000..8924920
--- /dev/null
+++ b/r_basicsr/models/esrgan_model.py
@@ -0,0 +1,83 @@
+import torch
+from collections import OrderedDict
+
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .srgan_model import SRGANModel
+
+
+@MODEL_REGISTRY.register()
+class ESRGANModel(SRGANModel):
+    """ESRGAN model for single image super-resolution."""
+
+    def optimize_parameters(self, current_iter):
+        # optimize net_g
+        for p in self.net_d.parameters():
+            p.requires_grad = False
+
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+
+        l_g_total = 0
+        loss_dict = OrderedDict()
+        if (current_iter % self.net_d_iters == 0 and current_iter > self.net_d_init_iters):
+            # pixel loss
+            if self.cri_pix:
+                l_g_pix = self.cri_pix(self.output, self.gt)
+                l_g_total += l_g_pix
+                loss_dict['l_g_pix'] = l_g_pix
+            # perceptual loss
+            if self.cri_perceptual:
+                l_g_percep, l_g_style = self.cri_perceptual(self.output, self.gt)
+                if l_g_percep is not None:
+                    l_g_total += l_g_percep
+                    loss_dict['l_g_percep'] = l_g_percep
+                if l_g_style is not None:
+                    l_g_total += l_g_style
+                    loss_dict['l_g_style'] = l_g_style
+            # gan loss (relativistic gan)
+            real_d_pred = self.net_d(self.gt).detach()
+            fake_g_pred = self.net_d(self.output)
+            l_g_real = self.cri_gan(real_d_pred - torch.mean(fake_g_pred), False, is_disc=False)
+            l_g_fake = self.cri_gan(fake_g_pred - torch.mean(real_d_pred), True, is_disc=False)
+            l_g_gan = (l_g_real + l_g_fake) / 2
+
+            l_g_total += l_g_gan
+            loss_dict['l_g_gan'] = l_g_gan
+
+            l_g_total.backward()
+            self.optimizer_g.step()
+
+        # optimize net_d
+        for p in self.net_d.parameters():
+            p.requires_grad = True
+
+        self.optimizer_d.zero_grad()
+        # gan loss (relativistic gan)
+
+        # In order to avoid the error in distributed training:
+        # "Error detected in CudnnBatchNormBackward: RuntimeError: one of
+        # the variables needed for gradient computation has been modified by
+        # an inplace operation",
+        # we separate the backwards for real and fake, and also detach the
+        # tensor for calculating mean.
+
+        # real
+        fake_d_pred = self.net_d(self.output).detach()
+        real_d_pred = self.net_d(self.gt)
+        l_d_real = self.cri_gan(real_d_pred - torch.mean(fake_d_pred), True, is_disc=True) * 0.5
+        l_d_real.backward()
+        # fake
+        fake_d_pred = self.net_d(self.output.detach())
+        l_d_fake = self.cri_gan(fake_d_pred - torch.mean(real_d_pred.detach()), False, is_disc=True) * 0.5
+        l_d_fake.backward()
+        self.optimizer_d.step()
+
+        loss_dict['l_d_real'] = l_d_real
+        loss_dict['l_d_fake'] = l_d_fake
+        loss_dict['out_d_real'] = torch.mean(real_d_pred.detach())
+        loss_dict['out_d_fake'] = torch.mean(fake_d_pred.detach())
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
diff --git a/r_basicsr/models/hifacegan_model.py b/r_basicsr/models/hifacegan_model.py
new file mode 100644
index 0000000..fd67d11
--- /dev/null
+++ b/r_basicsr/models/hifacegan_model.py
@@ -0,0 +1,288 @@
+import torch
+from collections import OrderedDict
+from os import path as osp
+from tqdm import tqdm
+
+from r_basicsr.archs import build_network
+from r_basicsr.losses import build_loss
+from r_basicsr.metrics import calculate_metric
+from r_basicsr.utils import imwrite, tensor2img
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .sr_model import SRModel
+
+
+@MODEL_REGISTRY.register()
+class HiFaceGANModel(SRModel):
+    """HiFaceGAN model for generic-purpose face restoration.
+    No prior modeling required, works for any degradations.
+    Currently doesn't support EMA for inference.
+    """
+
+    def init_training_settings(self):
+
+        train_opt = self.opt['train']
+        self.ema_decay = train_opt.get('ema_decay', 0)
+        if self.ema_decay > 0:
+            raise (NotImplementedError('HiFaceGAN does not support EMA now. Pass'))
+
+        self.net_g.train()
+
+        self.net_d = build_network(self.opt['network_d'])
+        self.net_d = self.model_to_device(self.net_d)
+        self.print_network(self.net_d)
+
+        # define losses
+        # HiFaceGAN does not use pixel loss by default
+        if train_opt.get('pixel_opt'):
+            self.cri_pix = build_loss(train_opt['pixel_opt']).to(self.device)
+        else:
+            self.cri_pix = None
+
+        if train_opt.get('perceptual_opt'):
+            self.cri_perceptual = build_loss(train_opt['perceptual_opt']).to(self.device)
+        else:
+            self.cri_perceptual = None
+
+        if train_opt.get('feature_matching_opt'):
+            self.cri_feat = build_loss(train_opt['feature_matching_opt']).to(self.device)
+        else:
+            self.cri_feat = None
+
+        if self.cri_pix is None and self.cri_perceptual is None:
+            raise ValueError('Both pixel and perceptual losses are None.')
+
+        if train_opt.get('gan_opt'):
+            self.cri_gan = build_loss(train_opt['gan_opt']).to(self.device)
+
+        self.net_d_iters = train_opt.get('net_d_iters', 1)
+        self.net_d_init_iters = train_opt.get('net_d_init_iters', 0)
+        # set up optimizers and schedulers
+        self.setup_optimizers()
+        self.setup_schedulers()
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        # optimizer g
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, self.net_g.parameters(), **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+        # optimizer d
+        optim_type = train_opt['optim_d'].pop('type')
+        self.optimizer_d = self.get_optimizer(optim_type, self.net_d.parameters(), **train_opt['optim_d'])
+        self.optimizers.append(self.optimizer_d)
+
+    def discriminate(self, input_lq, output, ground_truth):
+        """
+        This is a conditional (on the input) discriminator
+        In Batch Normalization, the fake and real images are
+        recommended to be in the same batch to avoid disparate
+        statistics in fake and real images.
+        So both fake and real images are fed to D all at once.
+        """
+        h, w = output.shape[-2:]
+        if output.shape[-2:] != input_lq.shape[-2:]:
+            lq = torch.nn.functional.interpolate(input_lq, (h, w))
+            real = torch.nn.functional.interpolate(ground_truth, (h, w))
+            fake_concat = torch.cat([lq, output], dim=1)
+            real_concat = torch.cat([lq, real], dim=1)
+        else:
+            fake_concat = torch.cat([input_lq, output], dim=1)
+            real_concat = torch.cat([input_lq, ground_truth], dim=1)
+
+        fake_and_real = torch.cat([fake_concat, real_concat], dim=0)
+        discriminator_out = self.net_d(fake_and_real)
+        pred_fake, pred_real = self._divide_pred(discriminator_out)
+        return pred_fake, pred_real
+
+    @staticmethod
+    def _divide_pred(pred):
+        """
+        Take the prediction of fake and real images from the combined batch.
+        The prediction contains the intermediate outputs of multiscale GAN,
+        so it's usually a list
+        """
+        if type(pred) == list:
+            fake = []
+            real = []
+            for p in pred:
+                fake.append([tensor[:tensor.size(0) // 2] for tensor in p])
+                real.append([tensor[tensor.size(0) // 2:] for tensor in p])
+        else:
+            fake = pred[:pred.size(0) // 2]
+            real = pred[pred.size(0) // 2:]
+
+        return fake, real
+
+    def optimize_parameters(self, current_iter):
+        # optimize net_g
+        for p in self.net_d.parameters():
+            p.requires_grad = False
+
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+
+        l_g_total = 0
+        loss_dict = OrderedDict()
+
+        if (current_iter % self.net_d_iters == 0 and current_iter > self.net_d_init_iters):
+            # pixel loss
+            if self.cri_pix:
+                l_g_pix = self.cri_pix(self.output, self.gt)
+                l_g_total += l_g_pix
+                loss_dict['l_g_pix'] = l_g_pix
+
+            # perceptual loss
+            if self.cri_perceptual:
+                l_g_percep, l_g_style = self.cri_perceptual(self.output, self.gt)
+                if l_g_percep is not None:
+                    l_g_total += l_g_percep
+                    loss_dict['l_g_percep'] = l_g_percep
+                if l_g_style is not None:
+                    l_g_total += l_g_style
+                    loss_dict['l_g_style'] = l_g_style
+
+            # Requires real prediction for feature matching loss
+            pred_fake, pred_real = self.discriminate(self.lq, self.output, self.gt)
+            l_g_gan = self.cri_gan(pred_fake, True, is_disc=False)
+            l_g_total += l_g_gan
+            loss_dict['l_g_gan'] = l_g_gan
+
+            # feature matching loss
+            if self.cri_feat:
+                l_g_feat = self.cri_feat(pred_fake, pred_real)
+                l_g_total += l_g_feat
+                loss_dict['l_g_feat'] = l_g_feat
+
+            l_g_total.backward()
+            self.optimizer_g.step()
+
+        # optimize net_d
+        for p in self.net_d.parameters():
+            p.requires_grad = True
+
+        self.optimizer_d.zero_grad()
+        # TODO: Benchmark test between HiFaceGAN and SRGAN implementation:
+        # SRGAN use the same fake output for discriminator update
+        # while HiFaceGAN regenerate a new output using updated net_g
+        # This should not make too much difference though. Stick to SRGAN now.
+        # -------------------------------------------------------------------
+        # ---------- Below are original HiFaceGAN code snippet --------------
+        # -------------------------------------------------------------------
+        # with torch.no_grad():
+        #    fake_image = self.net_g(self.lq)
+        #    fake_image = fake_image.detach()
+        #    fake_image.requires_grad_()
+        #    pred_fake, pred_real = self.discriminate(self.lq, fake_image, self.gt)
+
+        # real
+        pred_fake, pred_real = self.discriminate(self.lq, self.output.detach(), self.gt)
+        l_d_real = self.cri_gan(pred_real, True, is_disc=True)
+        loss_dict['l_d_real'] = l_d_real
+        # fake
+        l_d_fake = self.cri_gan(pred_fake, False, is_disc=True)
+        loss_dict['l_d_fake'] = l_d_fake
+
+        l_d_total = (l_d_real + l_d_fake) / 2
+        l_d_total.backward()
+        self.optimizer_d.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            print('HiFaceGAN does not support EMA now. pass')
+
+    def validation(self, dataloader, current_iter, tb_logger, save_img=False):
+        """
+        Warning: HiFaceGAN requires train() mode even for validation
+        For more info, see https://github.com/Lotayou/Face-Renovation/issues/31
+
+        Args:
+            dataloader (torch.utils.data.DataLoader): Validation dataloader.
+            current_iter (int): Current iteration.
+            tb_logger (tensorboard logger): Tensorboard logger.
+            save_img (bool): Whether to save images. Default: False.
+        """
+
+        if self.opt['network_g']['type'] in ('HiFaceGAN', 'SPADEGenerator'):
+            self.net_g.train()
+
+        if self.opt['dist']:
+            self.dist_validation(dataloader, current_iter, tb_logger, save_img)
+        else:
+            print('In HiFaceGANModel: The new metrics package is under development.' +
+                  'Using super method now (Only PSNR & SSIM are supported)')
+            super().nondist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        """
+        TODO: Validation using updated metric system
+        The metrics are now evaluated after all images have been tested
+        This allows batch processing, and also allows evaluation of
+        distributional metrics, such as:
+
+        @ Frechet Inception Distance: FID
+        @ Maximum Mean Discrepancy: MMD
+
+        Warning:
+            Need careful batch management for different inference settings.
+
+        """
+        dataset_name = dataloader.dataset.opt['name']
+        with_metrics = self.opt['val'].get('metrics') is not None
+        if with_metrics:
+            self.metric_results = dict()  # {metric: 0 for metric in self.opt['val']['metrics'].keys()}
+            sr_tensors = []
+            gt_tensors = []
+
+        pbar = tqdm(total=len(dataloader), unit='image')
+        for val_data in dataloader:
+            img_name = osp.splitext(osp.basename(val_data['lq_path'][0]))[0]
+            self.feed_data(val_data)
+            self.test()
+
+            visuals = self.get_current_visuals()  # detached cpu tensor, non-squeeze
+            sr_tensors.append(visuals['result'])
+            if 'gt' in visuals:
+                gt_tensors.append(visuals['gt'])
+                del self.gt
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            torch.cuda.empty_cache()
+
+            if save_img:
+                if self.opt['is_train']:
+                    save_img_path = osp.join(self.opt['path']['visualization'], img_name,
+                                             f'{img_name}_{current_iter}.png')
+                else:
+                    if self.opt['val']['suffix']:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                 f'{img_name}_{self.opt["val"]["suffix"]}.png')
+                    else:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                 f'{img_name}_{self.opt["name"]}.png')
+
+                imwrite(tensor2img(visuals['result']), save_img_path)
+
+            pbar.update(1)
+            pbar.set_description(f'Test {img_name}')
+        pbar.close()
+
+        if with_metrics:
+            sr_pack = torch.cat(sr_tensors, dim=0)
+            gt_pack = torch.cat(gt_tensors, dim=0)
+            # calculate metrics
+            for name, opt_ in self.opt['val']['metrics'].items():
+                # The new metric caller automatically returns mean value
+                # FIXME: ERROR: calculate_metric only supports two arguments. Now the codes cannot be successfully run
+                self.metric_results[name] = calculate_metric(dict(sr_pack=sr_pack, gt_pack=gt_pack), opt_)
+            self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def save(self, epoch, current_iter):
+        if hasattr(self, 'net_g_ema'):
+            print('HiFaceGAN does not support EMA now. Fallback to normal mode.')
+
+        self.save_network(self.net_g, 'net_g', current_iter)
+        self.save_network(self.net_d, 'net_d', current_iter)
+        self.save_training_state(epoch, current_iter)
diff --git a/r_basicsr/models/lr_scheduler.py b/r_basicsr/models/lr_scheduler.py
new file mode 100644
index 0000000..084122d
--- /dev/null
+++ b/r_basicsr/models/lr_scheduler.py
@@ -0,0 +1,96 @@
+import math
+from collections import Counter
+from torch.optim.lr_scheduler import _LRScheduler
+
+
+class MultiStepRestartLR(_LRScheduler):
+    """ MultiStep with restarts learning rate scheme.
+
+    Args:
+        optimizer (torch.nn.optimizer): Torch optimizer.
+        milestones (list): Iterations that will decrease learning rate.
+        gamma (float): Decrease ratio. Default: 0.1.
+        restarts (list): Restart iterations. Default: [0].
+        restart_weights (list): Restart weights at each restart iteration.
+            Default: [1].
+        last_epoch (int): Used in _LRScheduler. Default: -1.
+    """
+
+    def __init__(self, optimizer, milestones, gamma=0.1, restarts=(0, ), restart_weights=(1, ), last_epoch=-1):
+        self.milestones = Counter(milestones)
+        self.gamma = gamma
+        self.restarts = restarts
+        self.restart_weights = restart_weights
+        assert len(self.restarts) == len(self.restart_weights), 'restarts and their weights do not match.'
+        super(MultiStepRestartLR, self).__init__(optimizer, last_epoch)
+
+    def get_lr(self):
+        if self.last_epoch in self.restarts:
+            weight = self.restart_weights[self.restarts.index(self.last_epoch)]
+            return [group['initial_lr'] * weight for group in self.optimizer.param_groups]
+        if self.last_epoch not in self.milestones:
+            return [group['lr'] for group in self.optimizer.param_groups]
+        return [group['lr'] * self.gamma**self.milestones[self.last_epoch] for group in self.optimizer.param_groups]
+
+
+def get_position_from_periods(iteration, cumulative_period):
+    """Get the position from a period list.
+
+    It will return the index of the right-closest number in the period list.
+    For example, the cumulative_period = [100, 200, 300, 400],
+    if iteration == 50, return 0;
+    if iteration == 210, return 2;
+    if iteration == 300, return 2.
+
+    Args:
+        iteration (int): Current iteration.
+        cumulative_period (list[int]): Cumulative period list.
+
+    Returns:
+        int: The position of the right-closest number in the period list.
+    """
+    for i, period in enumerate(cumulative_period):
+        if iteration <= period:
+            return i
+
+
+class CosineAnnealingRestartLR(_LRScheduler):
+    """ Cosine annealing with restarts learning rate scheme.
+
+    An example of config:
+    periods = [10, 10, 10, 10]
+    restart_weights = [1, 0.5, 0.5, 0.5]
+    eta_min=1e-7
+
+    It has four cycles, each has 10 iterations. At 10th, 20th, 30th, the
+    scheduler will restart with the weights in restart_weights.
+
+    Args:
+        optimizer (torch.nn.optimizer): Torch optimizer.
+        periods (list): Period for each cosine anneling cycle.
+        restart_weights (list): Restart weights at each restart iteration.
+            Default: [1].
+        eta_min (float): The minimum lr. Default: 0.
+        last_epoch (int): Used in _LRScheduler. Default: -1.
+    """
+
+    def __init__(self, optimizer, periods, restart_weights=(1, ), eta_min=0, last_epoch=-1):
+        self.periods = periods
+        self.restart_weights = restart_weights
+        self.eta_min = eta_min
+        assert (len(self.periods) == len(
+            self.restart_weights)), 'periods and restart_weights should have the same length.'
+        self.cumulative_period = [sum(self.periods[0:i + 1]) for i in range(0, len(self.periods))]
+        super(CosineAnnealingRestartLR, self).__init__(optimizer, last_epoch)
+
+    def get_lr(self):
+        idx = get_position_from_periods(self.last_epoch, self.cumulative_period)
+        current_weight = self.restart_weights[idx]
+        nearest_restart = 0 if idx == 0 else self.cumulative_period[idx - 1]
+        current_period = self.periods[idx]
+
+        return [
+            self.eta_min + current_weight * 0.5 * (base_lr - self.eta_min) *
+            (1 + math.cos(math.pi * ((self.last_epoch - nearest_restart) / current_period)))
+            for base_lr in self.base_lrs
+        ]
diff --git a/r_basicsr/models/realesrgan_model.py b/r_basicsr/models/realesrgan_model.py
new file mode 100644
index 0000000..b05dafd
--- /dev/null
+++ b/r_basicsr/models/realesrgan_model.py
@@ -0,0 +1,267 @@
+import numpy as np
+import random
+import torch
+from collections import OrderedDict
+from torch.nn import functional as F
+
+from r_basicsr.data.degradations import random_add_gaussian_noise_pt, random_add_poisson_noise_pt
+from r_basicsr.data.transforms import paired_random_crop
+from r_basicsr.losses.loss_util import get_refined_artifact_map
+from r_basicsr.models.srgan_model import SRGANModel
+from r_basicsr.utils import DiffJPEG, USMSharp
+from r_basicsr.utils.img_process_util import filter2D
+from r_basicsr.utils.registry import MODEL_REGISTRY
+
+
+@MODEL_REGISTRY.register(suffix='basicsr')
+class RealESRGANModel(SRGANModel):
+    """RealESRGAN Model for Real-ESRGAN: Training Real-World Blind Super-Resolution with Pure Synthetic Data.
+
+    It mainly performs:
+    1. randomly synthesize LQ images in GPU tensors
+    2. optimize the networks with GAN training.
+    """
+
+    def __init__(self, opt):
+        super(RealESRGANModel, self).__init__(opt)
+        self.jpeger = DiffJPEG(differentiable=False).cuda()  # simulate JPEG compression artifacts
+        self.usm_sharpener = USMSharp().cuda()  # do usm sharpening
+        self.queue_size = opt.get('queue_size', 180)
+
+    @torch.no_grad()
+    def _dequeue_and_enqueue(self):
+        """It is the training pair pool for increasing the diversity in a batch.
+
+        Batch processing limits the diversity of synthetic degradations in a batch. For example, samples in a
+        batch could not have different resize scaling factors. Therefore, we employ this training pair pool
+        to increase the degradation diversity in a batch.
+        """
+        # initialize
+        b, c, h, w = self.lq.size()
+        if not hasattr(self, 'queue_lr'):
+            assert self.queue_size % b == 0, f'queue size {self.queue_size} should be divisible by batch size {b}'
+            self.queue_lr = torch.zeros(self.queue_size, c, h, w).cuda()
+            _, c, h, w = self.gt.size()
+            self.queue_gt = torch.zeros(self.queue_size, c, h, w).cuda()
+            self.queue_ptr = 0
+        if self.queue_ptr == self.queue_size:  # the pool is full
+            # do dequeue and enqueue
+            # shuffle
+            idx = torch.randperm(self.queue_size)
+            self.queue_lr = self.queue_lr[idx]
+            self.queue_gt = self.queue_gt[idx]
+            # get first b samples
+            lq_dequeue = self.queue_lr[0:b, :, :, :].clone()
+            gt_dequeue = self.queue_gt[0:b, :, :, :].clone()
+            # update the queue
+            self.queue_lr[0:b, :, :, :] = self.lq.clone()
+            self.queue_gt[0:b, :, :, :] = self.gt.clone()
+
+            self.lq = lq_dequeue
+            self.gt = gt_dequeue
+        else:
+            # only do enqueue
+            self.queue_lr[self.queue_ptr:self.queue_ptr + b, :, :, :] = self.lq.clone()
+            self.queue_gt[self.queue_ptr:self.queue_ptr + b, :, :, :] = self.gt.clone()
+            self.queue_ptr = self.queue_ptr + b
+
+    @torch.no_grad()
+    def feed_data(self, data):
+        """Accept data from dataloader, and then add two-order degradations to obtain LQ images.
+        """
+        if self.is_train and self.opt.get('high_order_degradation', True):
+            # training data synthesis
+            self.gt = data['gt'].to(self.device)
+            self.gt_usm = self.usm_sharpener(self.gt)
+
+            self.kernel1 = data['kernel1'].to(self.device)
+            self.kernel2 = data['kernel2'].to(self.device)
+            self.sinc_kernel = data['sinc_kernel'].to(self.device)
+
+            ori_h, ori_w = self.gt.size()[2:4]
+
+            # ----------------------- The first degradation process ----------------------- #
+            # blur
+            out = filter2D(self.gt_usm, self.kernel1)
+            # random resize
+            updown_type = random.choices(['up', 'down', 'keep'], self.opt['resize_prob'])[0]
+            if updown_type == 'up':
+                scale = np.random.uniform(1, self.opt['resize_range'][1])
+            elif updown_type == 'down':
+                scale = np.random.uniform(self.opt['resize_range'][0], 1)
+            else:
+                scale = 1
+            mode = random.choice(['area', 'bilinear', 'bicubic'])
+            out = F.interpolate(out, scale_factor=scale, mode=mode)
+            # add noise
+            gray_noise_prob = self.opt['gray_noise_prob']
+            if np.random.uniform() < self.opt['gaussian_noise_prob']:
+                out = random_add_gaussian_noise_pt(
+                    out, sigma_range=self.opt['noise_range'], clip=True, rounds=False, gray_prob=gray_noise_prob)
+            else:
+                out = random_add_poisson_noise_pt(
+                    out,
+                    scale_range=self.opt['poisson_scale_range'],
+                    gray_prob=gray_noise_prob,
+                    clip=True,
+                    rounds=False)
+            # JPEG compression
+            jpeg_p = out.new_zeros(out.size(0)).uniform_(*self.opt['jpeg_range'])
+            out = torch.clamp(out, 0, 1)  # clamp to [0, 1], otherwise JPEGer will result in unpleasant artifacts
+            out = self.jpeger(out, quality=jpeg_p)
+
+            # ----------------------- The second degradation process ----------------------- #
+            # blur
+            if np.random.uniform() < self.opt['second_blur_prob']:
+                out = filter2D(out, self.kernel2)
+            # random resize
+            updown_type = random.choices(['up', 'down', 'keep'], self.opt['resize_prob2'])[0]
+            if updown_type == 'up':
+                scale = np.random.uniform(1, self.opt['resize_range2'][1])
+            elif updown_type == 'down':
+                scale = np.random.uniform(self.opt['resize_range2'][0], 1)
+            else:
+                scale = 1
+            mode = random.choice(['area', 'bilinear', 'bicubic'])
+            out = F.interpolate(
+                out, size=(int(ori_h / self.opt['scale'] * scale), int(ori_w / self.opt['scale'] * scale)), mode=mode)
+            # add noise
+            gray_noise_prob = self.opt['gray_noise_prob2']
+            if np.random.uniform() < self.opt['gaussian_noise_prob2']:
+                out = random_add_gaussian_noise_pt(
+                    out, sigma_range=self.opt['noise_range2'], clip=True, rounds=False, gray_prob=gray_noise_prob)
+            else:
+                out = random_add_poisson_noise_pt(
+                    out,
+                    scale_range=self.opt['poisson_scale_range2'],
+                    gray_prob=gray_noise_prob,
+                    clip=True,
+                    rounds=False)
+
+            # JPEG compression + the final sinc filter
+            # We also need to resize images to desired sizes. We group [resize back + sinc filter] together
+            # as one operation.
+            # We consider two orders:
+            #   1. [resize back + sinc filter] + JPEG compression
+            #   2. JPEG compression + [resize back + sinc filter]
+            # Empirically, we find other combinations (sinc + JPEG + Resize) will introduce twisted lines.
+            if np.random.uniform() < 0.5:
+                # resize back + the final sinc filter
+                mode = random.choice(['area', 'bilinear', 'bicubic'])
+                out = F.interpolate(out, size=(ori_h // self.opt['scale'], ori_w // self.opt['scale']), mode=mode)
+                out = filter2D(out, self.sinc_kernel)
+                # JPEG compression
+                jpeg_p = out.new_zeros(out.size(0)).uniform_(*self.opt['jpeg_range2'])
+                out = torch.clamp(out, 0, 1)
+                out = self.jpeger(out, quality=jpeg_p)
+            else:
+                # JPEG compression
+                jpeg_p = out.new_zeros(out.size(0)).uniform_(*self.opt['jpeg_range2'])
+                out = torch.clamp(out, 0, 1)
+                out = self.jpeger(out, quality=jpeg_p)
+                # resize back + the final sinc filter
+                mode = random.choice(['area', 'bilinear', 'bicubic'])
+                out = F.interpolate(out, size=(ori_h // self.opt['scale'], ori_w // self.opt['scale']), mode=mode)
+                out = filter2D(out, self.sinc_kernel)
+
+            # clamp and round
+            self.lq = torch.clamp((out * 255.0).round(), 0, 255) / 255.
+
+            # random crop
+            gt_size = self.opt['gt_size']
+            (self.gt, self.gt_usm), self.lq = paired_random_crop([self.gt, self.gt_usm], self.lq, gt_size,
+                                                                 self.opt['scale'])
+
+            # training pair pool
+            self._dequeue_and_enqueue()
+            # sharpen self.gt again, as we have changed the self.gt with self._dequeue_and_enqueue
+            self.gt_usm = self.usm_sharpener(self.gt)
+            self.lq = self.lq.contiguous()  # for the warning: grad and param do not obey the gradient layout contract
+        else:
+            # for paired training or validation
+            self.lq = data['lq'].to(self.device)
+            if 'gt' in data:
+                self.gt = data['gt'].to(self.device)
+                self.gt_usm = self.usm_sharpener(self.gt)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        # do not use the synthetic process during validation
+        self.is_train = False
+        super(RealESRGANModel, self).nondist_validation(dataloader, current_iter, tb_logger, save_img)
+        self.is_train = True
+
+    def optimize_parameters(self, current_iter):
+        # usm sharpening
+        l1_gt = self.gt_usm
+        percep_gt = self.gt_usm
+        gan_gt = self.gt_usm
+        if self.opt['l1_gt_usm'] is False:
+            l1_gt = self.gt
+        if self.opt['percep_gt_usm'] is False:
+            percep_gt = self.gt
+        if self.opt['gan_gt_usm'] is False:
+            gan_gt = self.gt
+
+        # optimize net_g
+        for p in self.net_d.parameters():
+            p.requires_grad = False
+
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+        if self.cri_ldl:
+            self.output_ema = self.net_g_ema(self.lq)
+
+        l_g_total = 0
+        loss_dict = OrderedDict()
+        if (current_iter % self.net_d_iters == 0 and current_iter > self.net_d_init_iters):
+            # pixel loss
+            if self.cri_pix:
+                l_g_pix = self.cri_pix(self.output, l1_gt)
+                l_g_total += l_g_pix
+                loss_dict['l_g_pix'] = l_g_pix
+            if self.cri_ldl:
+                pixel_weight = get_refined_artifact_map(self.gt, self.output, self.output_ema, 7)
+                l_g_ldl = self.cri_ldl(torch.mul(pixel_weight, self.output), torch.mul(pixel_weight, self.gt))
+                l_g_total += l_g_ldl
+                loss_dict['l_g_ldl'] = l_g_ldl
+            # perceptual loss
+            if self.cri_perceptual:
+                l_g_percep, l_g_style = self.cri_perceptual(self.output, percep_gt)
+                if l_g_percep is not None:
+                    l_g_total += l_g_percep
+                    loss_dict['l_g_percep'] = l_g_percep
+                if l_g_style is not None:
+                    l_g_total += l_g_style
+                    loss_dict['l_g_style'] = l_g_style
+            # gan loss
+            fake_g_pred = self.net_d(self.output)
+            l_g_gan = self.cri_gan(fake_g_pred, True, is_disc=False)
+            l_g_total += l_g_gan
+            loss_dict['l_g_gan'] = l_g_gan
+
+            l_g_total.backward()
+            self.optimizer_g.step()
+
+        # optimize net_d
+        for p in self.net_d.parameters():
+            p.requires_grad = True
+
+        self.optimizer_d.zero_grad()
+        # real
+        real_d_pred = self.net_d(gan_gt)
+        l_d_real = self.cri_gan(real_d_pred, True, is_disc=True)
+        loss_dict['l_d_real'] = l_d_real
+        loss_dict['out_d_real'] = torch.mean(real_d_pred.detach())
+        l_d_real.backward()
+        # fake
+        fake_d_pred = self.net_d(self.output.detach().clone())  # clone for pt1.9
+        l_d_fake = self.cri_gan(fake_d_pred, False, is_disc=True)
+        loss_dict['l_d_fake'] = l_d_fake
+        loss_dict['out_d_fake'] = torch.mean(fake_d_pred.detach())
+        l_d_fake.backward()
+        self.optimizer_d.step()
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
diff --git a/r_basicsr/models/realesrnet_model.py b/r_basicsr/models/realesrnet_model.py
new file mode 100644
index 0000000..2e8dc65
--- /dev/null
+++ b/r_basicsr/models/realesrnet_model.py
@@ -0,0 +1,189 @@
+import numpy as np
+import random
+import torch
+from torch.nn import functional as F
+
+from r_basicsr.data.degradations import random_add_gaussian_noise_pt, random_add_poisson_noise_pt
+from r_basicsr.data.transforms import paired_random_crop
+from r_basicsr.models.sr_model import SRModel
+from r_basicsr.utils import DiffJPEG, USMSharp
+from r_basicsr.utils.img_process_util import filter2D
+from r_basicsr.utils.registry import MODEL_REGISTRY
+
+
+@MODEL_REGISTRY.register(suffix='basicsr')
+class RealESRNetModel(SRModel):
+    """RealESRNet Model for Real-ESRGAN: Training Real-World Blind Super-Resolution with Pure Synthetic Data.
+
+    It is trained without GAN losses.
+    It mainly performs:
+    1. randomly synthesize LQ images in GPU tensors
+    2. optimize the networks with GAN training.
+    """
+
+    def __init__(self, opt):
+        super(RealESRNetModel, self).__init__(opt)
+        self.jpeger = DiffJPEG(differentiable=False).cuda()  # simulate JPEG compression artifacts
+        self.usm_sharpener = USMSharp().cuda()  # do usm sharpening
+        self.queue_size = opt.get('queue_size', 180)
+
+    @torch.no_grad()
+    def _dequeue_and_enqueue(self):
+        """It is the training pair pool for increasing the diversity in a batch.
+
+        Batch processing limits the diversity of synthetic degradations in a batch. For example, samples in a
+        batch could not have different resize scaling factors. Therefore, we employ this training pair pool
+        to increase the degradation diversity in a batch.
+        """
+        # initialize
+        b, c, h, w = self.lq.size()
+        if not hasattr(self, 'queue_lr'):
+            assert self.queue_size % b == 0, f'queue size {self.queue_size} should be divisible by batch size {b}'
+            self.queue_lr = torch.zeros(self.queue_size, c, h, w).cuda()
+            _, c, h, w = self.gt.size()
+            self.queue_gt = torch.zeros(self.queue_size, c, h, w).cuda()
+            self.queue_ptr = 0
+        if self.queue_ptr == self.queue_size:  # the pool is full
+            # do dequeue and enqueue
+            # shuffle
+            idx = torch.randperm(self.queue_size)
+            self.queue_lr = self.queue_lr[idx]
+            self.queue_gt = self.queue_gt[idx]
+            # get first b samples
+            lq_dequeue = self.queue_lr[0:b, :, :, :].clone()
+            gt_dequeue = self.queue_gt[0:b, :, :, :].clone()
+            # update the queue
+            self.queue_lr[0:b, :, :, :] = self.lq.clone()
+            self.queue_gt[0:b, :, :, :] = self.gt.clone()
+
+            self.lq = lq_dequeue
+            self.gt = gt_dequeue
+        else:
+            # only do enqueue
+            self.queue_lr[self.queue_ptr:self.queue_ptr + b, :, :, :] = self.lq.clone()
+            self.queue_gt[self.queue_ptr:self.queue_ptr + b, :, :, :] = self.gt.clone()
+            self.queue_ptr = self.queue_ptr + b
+
+    @torch.no_grad()
+    def feed_data(self, data):
+        """Accept data from dataloader, and then add two-order degradations to obtain LQ images.
+        """
+        if self.is_train and self.opt.get('high_order_degradation', True):
+            # training data synthesis
+            self.gt = data['gt'].to(self.device)
+            # USM sharpen the GT images
+            if self.opt['gt_usm'] is True:
+                self.gt = self.usm_sharpener(self.gt)
+
+            self.kernel1 = data['kernel1'].to(self.device)
+            self.kernel2 = data['kernel2'].to(self.device)
+            self.sinc_kernel = data['sinc_kernel'].to(self.device)
+
+            ori_h, ori_w = self.gt.size()[2:4]
+
+            # ----------------------- The first degradation process ----------------------- #
+            # blur
+            out = filter2D(self.gt, self.kernel1)
+            # random resize
+            updown_type = random.choices(['up', 'down', 'keep'], self.opt['resize_prob'])[0]
+            if updown_type == 'up':
+                scale = np.random.uniform(1, self.opt['resize_range'][1])
+            elif updown_type == 'down':
+                scale = np.random.uniform(self.opt['resize_range'][0], 1)
+            else:
+                scale = 1
+            mode = random.choice(['area', 'bilinear', 'bicubic'])
+            out = F.interpolate(out, scale_factor=scale, mode=mode)
+            # add noise
+            gray_noise_prob = self.opt['gray_noise_prob']
+            if np.random.uniform() < self.opt['gaussian_noise_prob']:
+                out = random_add_gaussian_noise_pt(
+                    out, sigma_range=self.opt['noise_range'], clip=True, rounds=False, gray_prob=gray_noise_prob)
+            else:
+                out = random_add_poisson_noise_pt(
+                    out,
+                    scale_range=self.opt['poisson_scale_range'],
+                    gray_prob=gray_noise_prob,
+                    clip=True,
+                    rounds=False)
+            # JPEG compression
+            jpeg_p = out.new_zeros(out.size(0)).uniform_(*self.opt['jpeg_range'])
+            out = torch.clamp(out, 0, 1)  # clamp to [0, 1], otherwise JPEGer will result in unpleasant artifacts
+            out = self.jpeger(out, quality=jpeg_p)
+
+            # ----------------------- The second degradation process ----------------------- #
+            # blur
+            if np.random.uniform() < self.opt['second_blur_prob']:
+                out = filter2D(out, self.kernel2)
+            # random resize
+            updown_type = random.choices(['up', 'down', 'keep'], self.opt['resize_prob2'])[0]
+            if updown_type == 'up':
+                scale = np.random.uniform(1, self.opt['resize_range2'][1])
+            elif updown_type == 'down':
+                scale = np.random.uniform(self.opt['resize_range2'][0], 1)
+            else:
+                scale = 1
+            mode = random.choice(['area', 'bilinear', 'bicubic'])
+            out = F.interpolate(
+                out, size=(int(ori_h / self.opt['scale'] * scale), int(ori_w / self.opt['scale'] * scale)), mode=mode)
+            # add noise
+            gray_noise_prob = self.opt['gray_noise_prob2']
+            if np.random.uniform() < self.opt['gaussian_noise_prob2']:
+                out = random_add_gaussian_noise_pt(
+                    out, sigma_range=self.opt['noise_range2'], clip=True, rounds=False, gray_prob=gray_noise_prob)
+            else:
+                out = random_add_poisson_noise_pt(
+                    out,
+                    scale_range=self.opt['poisson_scale_range2'],
+                    gray_prob=gray_noise_prob,
+                    clip=True,
+                    rounds=False)
+
+            # JPEG compression + the final sinc filter
+            # We also need to resize images to desired sizes. We group [resize back + sinc filter] together
+            # as one operation.
+            # We consider two orders:
+            #   1. [resize back + sinc filter] + JPEG compression
+            #   2. JPEG compression + [resize back + sinc filter]
+            # Empirically, we find other combinations (sinc + JPEG + Resize) will introduce twisted lines.
+            if np.random.uniform() < 0.5:
+                # resize back + the final sinc filter
+                mode = random.choice(['area', 'bilinear', 'bicubic'])
+                out = F.interpolate(out, size=(ori_h // self.opt['scale'], ori_w // self.opt['scale']), mode=mode)
+                out = filter2D(out, self.sinc_kernel)
+                # JPEG compression
+                jpeg_p = out.new_zeros(out.size(0)).uniform_(*self.opt['jpeg_range2'])
+                out = torch.clamp(out, 0, 1)
+                out = self.jpeger(out, quality=jpeg_p)
+            else:
+                # JPEG compression
+                jpeg_p = out.new_zeros(out.size(0)).uniform_(*self.opt['jpeg_range2'])
+                out = torch.clamp(out, 0, 1)
+                out = self.jpeger(out, quality=jpeg_p)
+                # resize back + the final sinc filter
+                mode = random.choice(['area', 'bilinear', 'bicubic'])
+                out = F.interpolate(out, size=(ori_h // self.opt['scale'], ori_w // self.opt['scale']), mode=mode)
+                out = filter2D(out, self.sinc_kernel)
+
+            # clamp and round
+            self.lq = torch.clamp((out * 255.0).round(), 0, 255) / 255.
+
+            # random crop
+            gt_size = self.opt['gt_size']
+            self.gt, self.lq = paired_random_crop(self.gt, self.lq, gt_size, self.opt['scale'])
+
+            # training pair pool
+            self._dequeue_and_enqueue()
+            self.lq = self.lq.contiguous()  # for the warning: grad and param do not obey the gradient layout contract
+        else:
+            # for paired training or validation
+            self.lq = data['lq'].to(self.device)
+            if 'gt' in data:
+                self.gt = data['gt'].to(self.device)
+                self.gt_usm = self.usm_sharpener(self.gt)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        # do not use the synthetic process during validation
+        self.is_train = False
+        super(RealESRNetModel, self).nondist_validation(dataloader, current_iter, tb_logger, save_img)
+        self.is_train = True
diff --git a/r_basicsr/models/sr_model.py b/r_basicsr/models/sr_model.py
new file mode 100644
index 0000000..f6e37e9
--- /dev/null
+++ b/r_basicsr/models/sr_model.py
@@ -0,0 +1,231 @@
+import torch
+from collections import OrderedDict
+from os import path as osp
+from tqdm import tqdm
+
+from r_basicsr.archs import build_network
+from r_basicsr.losses import build_loss
+from r_basicsr.metrics import calculate_metric
+from r_basicsr.utils import get_root_logger, imwrite, tensor2img
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .base_model import BaseModel
+
+
+@MODEL_REGISTRY.register()
+class SRModel(BaseModel):
+    """Base SR model for single image super-resolution."""
+
+    def __init__(self, opt):
+        super(SRModel, self).__init__(opt)
+
+        # define network
+        self.net_g = build_network(opt['network_g'])
+        self.net_g = self.model_to_device(self.net_g)
+        self.print_network(self.net_g)
+
+        # load pretrained models
+        load_path = self.opt['path'].get('pretrain_network_g', None)
+        if load_path is not None:
+            param_key = self.opt['path'].get('param_key_g', 'params')
+            self.load_network(self.net_g, load_path, self.opt['path'].get('strict_load_g', True), param_key)
+
+        if self.is_train:
+            self.init_training_settings()
+
+    def init_training_settings(self):
+        self.net_g.train()
+        train_opt = self.opt['train']
+
+        self.ema_decay = train_opt.get('ema_decay', 0)
+        if self.ema_decay > 0:
+            logger = get_root_logger()
+            logger.info(f'Use Exponential Moving Average with decay: {self.ema_decay}')
+            # define network net_g with Exponential Moving Average (EMA)
+            # net_g_ema is used only for testing on one GPU and saving
+            # There is no need to wrap with DistributedDataParallel
+            self.net_g_ema = build_network(self.opt['network_g']).to(self.device)
+            # load pretrained model
+            load_path = self.opt['path'].get('pretrain_network_g', None)
+            if load_path is not None:
+                self.load_network(self.net_g_ema, load_path, self.opt['path'].get('strict_load_g', True), 'params_ema')
+            else:
+                self.model_ema(0)  # copy net_g weight
+            self.net_g_ema.eval()
+
+        # define losses
+        if train_opt.get('pixel_opt'):
+            self.cri_pix = build_loss(train_opt['pixel_opt']).to(self.device)
+        else:
+            self.cri_pix = None
+
+        if train_opt.get('perceptual_opt'):
+            self.cri_perceptual = build_loss(train_opt['perceptual_opt']).to(self.device)
+        else:
+            self.cri_perceptual = None
+
+        if self.cri_pix is None and self.cri_perceptual is None:
+            raise ValueError('Both pixel and perceptual losses are None.')
+
+        # set up optimizers and schedulers
+        self.setup_optimizers()
+        self.setup_schedulers()
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        optim_params = []
+        for k, v in self.net_g.named_parameters():
+            if v.requires_grad:
+                optim_params.append(v)
+            else:
+                logger = get_root_logger()
+                logger.warning(f'Params {k} will not be optimized.')
+
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+
+    def feed_data(self, data):
+        self.lq = data['lq'].to(self.device)
+        if 'gt' in data:
+            self.gt = data['gt'].to(self.device)
+
+    def optimize_parameters(self, current_iter):
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+
+        l_total = 0
+        loss_dict = OrderedDict()
+        # pixel loss
+        if self.cri_pix:
+            l_pix = self.cri_pix(self.output, self.gt)
+            l_total += l_pix
+            loss_dict['l_pix'] = l_pix
+        # perceptual loss
+        if self.cri_perceptual:
+            l_percep, l_style = self.cri_perceptual(self.output, self.gt)
+            if l_percep is not None:
+                l_total += l_percep
+                loss_dict['l_percep'] = l_percep
+            if l_style is not None:
+                l_total += l_style
+                loss_dict['l_style'] = l_style
+
+        l_total.backward()
+        self.optimizer_g.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
+
+    def test(self):
+        if hasattr(self, 'net_g_ema'):
+            self.net_g_ema.eval()
+            with torch.no_grad():
+                self.output = self.net_g_ema(self.lq)
+        else:
+            self.net_g.eval()
+            with torch.no_grad():
+                self.output = self.net_g(self.lq)
+            self.net_g.train()
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        if self.opt['rank'] == 0:
+            self.nondist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset_name = dataloader.dataset.opt['name']
+        with_metrics = self.opt['val'].get('metrics') is not None
+        use_pbar = self.opt['val'].get('pbar', False)
+
+        if with_metrics:
+            if not hasattr(self, 'metric_results'):  # only execute in the first run
+                self.metric_results = {metric: 0 for metric in self.opt['val']['metrics'].keys()}
+            # initialize the best metric results for each dataset_name (supporting multiple validation datasets)
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        if with_metrics:
+            self.metric_results = {metric: 0 for metric in self.metric_results}
+
+        metric_data = dict()
+        if use_pbar:
+            pbar = tqdm(total=len(dataloader), unit='image')
+
+        for idx, val_data in enumerate(dataloader):
+            img_name = osp.splitext(osp.basename(val_data['lq_path'][0]))[0]
+            self.feed_data(val_data)
+            self.test()
+
+            visuals = self.get_current_visuals()
+            sr_img = tensor2img([visuals['result']])
+            metric_data['img'] = sr_img
+            if 'gt' in visuals:
+                gt_img = tensor2img([visuals['gt']])
+                metric_data['img2'] = gt_img
+                del self.gt
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            torch.cuda.empty_cache()
+
+            if save_img:
+                if self.opt['is_train']:
+                    save_img_path = osp.join(self.opt['path']['visualization'], img_name,
+                                             f'{img_name}_{current_iter}.png')
+                else:
+                    if self.opt['val']['suffix']:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                 f'{img_name}_{self.opt["val"]["suffix"]}.png')
+                    else:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                 f'{img_name}_{self.opt["name"]}.png')
+                imwrite(sr_img, save_img_path)
+
+            if with_metrics:
+                # calculate metrics
+                for name, opt_ in self.opt['val']['metrics'].items():
+                    self.metric_results[name] += calculate_metric(metric_data, opt_)
+            if use_pbar:
+                pbar.update(1)
+                pbar.set_description(f'Test {img_name}')
+        if use_pbar:
+            pbar.close()
+
+        if with_metrics:
+            for metric in self.metric_results.keys():
+                self.metric_results[metric] /= (idx + 1)
+                # update the best metric result
+                self._update_best_metric_result(dataset_name, metric, self.metric_results[metric], current_iter)
+
+            self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def _log_validation_metric_values(self, current_iter, dataset_name, tb_logger):
+        log_str = f'Validation {dataset_name}\n'
+        for metric, value in self.metric_results.items():
+            log_str += f'\t # {metric}: {value:.4f}'
+            if hasattr(self, 'best_metric_results'):
+                log_str += (f'\tBest: {self.best_metric_results[dataset_name][metric]["val"]:.4f} @ '
+                            f'{self.best_metric_results[dataset_name][metric]["iter"]} iter')
+            log_str += '\n'
+
+        logger = get_root_logger()
+        logger.info(log_str)
+        if tb_logger:
+            for metric, value in self.metric_results.items():
+                tb_logger.add_scalar(f'metrics/{dataset_name}/{metric}', value, current_iter)
+
+    def get_current_visuals(self):
+        out_dict = OrderedDict()
+        out_dict['lq'] = self.lq.detach().cpu()
+        out_dict['result'] = self.output.detach().cpu()
+        if hasattr(self, 'gt'):
+            out_dict['gt'] = self.gt.detach().cpu()
+        return out_dict
+
+    def save(self, epoch, current_iter):
+        if hasattr(self, 'net_g_ema'):
+            self.save_network([self.net_g, self.net_g_ema], 'net_g', current_iter, param_key=['params', 'params_ema'])
+        else:
+            self.save_network(self.net_g, 'net_g', current_iter)
+        self.save_training_state(epoch, current_iter)
diff --git a/r_basicsr/models/srgan_model.py b/r_basicsr/models/srgan_model.py
new file mode 100644
index 0000000..a562a7d
--- /dev/null
+++ b/r_basicsr/models/srgan_model.py
@@ -0,0 +1,149 @@
+import torch
+from collections import OrderedDict
+
+from r_basicsr.archs import build_network
+from r_basicsr.losses import build_loss
+from r_basicsr.utils import get_root_logger
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .sr_model import SRModel
+
+
+@MODEL_REGISTRY.register()
+class SRGANModel(SRModel):
+    """SRGAN model for single image super-resolution."""
+
+    def init_training_settings(self):
+        train_opt = self.opt['train']
+
+        self.ema_decay = train_opt.get('ema_decay', 0)
+        if self.ema_decay > 0:
+            logger = get_root_logger()
+            logger.info(f'Use Exponential Moving Average with decay: {self.ema_decay}')
+            # define network net_g with Exponential Moving Average (EMA)
+            # net_g_ema is used only for testing on one GPU and saving
+            # There is no need to wrap with DistributedDataParallel
+            self.net_g_ema = build_network(self.opt['network_g']).to(self.device)
+            # load pretrained model
+            load_path = self.opt['path'].get('pretrain_network_g', None)
+            if load_path is not None:
+                self.load_network(self.net_g_ema, load_path, self.opt['path'].get('strict_load_g', True), 'params_ema')
+            else:
+                self.model_ema(0)  # copy net_g weight
+            self.net_g_ema.eval()
+
+        # define network net_d
+        self.net_d = build_network(self.opt['network_d'])
+        self.net_d = self.model_to_device(self.net_d)
+        self.print_network(self.net_d)
+
+        # load pretrained models
+        load_path = self.opt['path'].get('pretrain_network_d', None)
+        if load_path is not None:
+            param_key = self.opt['path'].get('param_key_d', 'params')
+            self.load_network(self.net_d, load_path, self.opt['path'].get('strict_load_d', True), param_key)
+
+        self.net_g.train()
+        self.net_d.train()
+
+        # define losses
+        if train_opt.get('pixel_opt'):
+            self.cri_pix = build_loss(train_opt['pixel_opt']).to(self.device)
+        else:
+            self.cri_pix = None
+
+        if train_opt.get('ldl_opt'):
+            self.cri_ldl = build_loss(train_opt['ldl_opt']).to(self.device)
+        else:
+            self.cri_ldl = None
+
+        if train_opt.get('perceptual_opt'):
+            self.cri_perceptual = build_loss(train_opt['perceptual_opt']).to(self.device)
+        else:
+            self.cri_perceptual = None
+
+        if train_opt.get('gan_opt'):
+            self.cri_gan = build_loss(train_opt['gan_opt']).to(self.device)
+
+        self.net_d_iters = train_opt.get('net_d_iters', 1)
+        self.net_d_init_iters = train_opt.get('net_d_init_iters', 0)
+
+        # set up optimizers and schedulers
+        self.setup_optimizers()
+        self.setup_schedulers()
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        # optimizer g
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, self.net_g.parameters(), **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+        # optimizer d
+        optim_type = train_opt['optim_d'].pop('type')
+        self.optimizer_d = self.get_optimizer(optim_type, self.net_d.parameters(), **train_opt['optim_d'])
+        self.optimizers.append(self.optimizer_d)
+
+    def optimize_parameters(self, current_iter):
+        # optimize net_g
+        for p in self.net_d.parameters():
+            p.requires_grad = False
+
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+
+        l_g_total = 0
+        loss_dict = OrderedDict()
+        if (current_iter % self.net_d_iters == 0 and current_iter > self.net_d_init_iters):
+            # pixel loss
+            if self.cri_pix:
+                l_g_pix = self.cri_pix(self.output, self.gt)
+                l_g_total += l_g_pix
+                loss_dict['l_g_pix'] = l_g_pix
+            # perceptual loss
+            if self.cri_perceptual:
+                l_g_percep, l_g_style = self.cri_perceptual(self.output, self.gt)
+                if l_g_percep is not None:
+                    l_g_total += l_g_percep
+                    loss_dict['l_g_percep'] = l_g_percep
+                if l_g_style is not None:
+                    l_g_total += l_g_style
+                    loss_dict['l_g_style'] = l_g_style
+            # gan loss
+            fake_g_pred = self.net_d(self.output)
+            l_g_gan = self.cri_gan(fake_g_pred, True, is_disc=False)
+            l_g_total += l_g_gan
+            loss_dict['l_g_gan'] = l_g_gan
+
+            l_g_total.backward()
+            self.optimizer_g.step()
+
+        # optimize net_d
+        for p in self.net_d.parameters():
+            p.requires_grad = True
+
+        self.optimizer_d.zero_grad()
+        # real
+        real_d_pred = self.net_d(self.gt)
+        l_d_real = self.cri_gan(real_d_pred, True, is_disc=True)
+        loss_dict['l_d_real'] = l_d_real
+        loss_dict['out_d_real'] = torch.mean(real_d_pred.detach())
+        l_d_real.backward()
+        # fake
+        fake_d_pred = self.net_d(self.output.detach())
+        l_d_fake = self.cri_gan(fake_d_pred, False, is_disc=True)
+        loss_dict['l_d_fake'] = l_d_fake
+        loss_dict['out_d_fake'] = torch.mean(fake_d_pred.detach())
+        l_d_fake.backward()
+        self.optimizer_d.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
+
+    def save(self, epoch, current_iter):
+        if hasattr(self, 'net_g_ema'):
+            self.save_network([self.net_g, self.net_g_ema], 'net_g', current_iter, param_key=['params', 'params_ema'])
+        else:
+            self.save_network(self.net_g, 'net_g', current_iter)
+        self.save_network(self.net_d, 'net_d', current_iter)
+        self.save_training_state(epoch, current_iter)
diff --git a/r_basicsr/models/stylegan2_model.py b/r_basicsr/models/stylegan2_model.py
new file mode 100644
index 0000000..58a38ae
--- /dev/null
+++ b/r_basicsr/models/stylegan2_model.py
@@ -0,0 +1,283 @@
+import cv2
+import math
+import numpy as np
+import random
+import torch
+from collections import OrderedDict
+from os import path as osp
+
+from r_basicsr.archs import build_network
+from r_basicsr.losses import build_loss
+from r_basicsr.losses.gan_loss import g_path_regularize, r1_penalty
+from r_basicsr.utils import imwrite, tensor2img
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .base_model import BaseModel
+
+
+@MODEL_REGISTRY.register()
+class StyleGAN2Model(BaseModel):
+    """StyleGAN2 model."""
+
+    def __init__(self, opt):
+        super(StyleGAN2Model, self).__init__(opt)
+
+        # define network net_g
+        self.net_g = build_network(opt['network_g'])
+        self.net_g = self.model_to_device(self.net_g)
+        self.print_network(self.net_g)
+        # load pretrained model
+        load_path = self.opt['path'].get('pretrain_network_g', None)
+        if load_path is not None:
+            param_key = self.opt['path'].get('param_key_g', 'params')
+            self.load_network(self.net_g, load_path, self.opt['path'].get('strict_load_g', True), param_key)
+
+        # latent dimension: self.num_style_feat
+        self.num_style_feat = opt['network_g']['num_style_feat']
+        num_val_samples = self.opt['val'].get('num_val_samples', 16)
+        self.fixed_sample = torch.randn(num_val_samples, self.num_style_feat, device=self.device)
+
+        if self.is_train:
+            self.init_training_settings()
+
+    def init_training_settings(self):
+        train_opt = self.opt['train']
+
+        # define network net_d
+        self.net_d = build_network(self.opt['network_d'])
+        self.net_d = self.model_to_device(self.net_d)
+        self.print_network(self.net_d)
+
+        # load pretrained model
+        load_path = self.opt['path'].get('pretrain_network_d', None)
+        if load_path is not None:
+            param_key = self.opt['path'].get('param_key_d', 'params')
+            self.load_network(self.net_d, load_path, self.opt['path'].get('strict_load_d', True), param_key)
+
+        # define network net_g with Exponential Moving Average (EMA)
+        # net_g_ema only used for testing on one GPU and saving, do not need to
+        # wrap with DistributedDataParallel
+        self.net_g_ema = build_network(self.opt['network_g']).to(self.device)
+        # load pretrained model
+        load_path = self.opt['path'].get('pretrain_network_g', None)
+        if load_path is not None:
+            self.load_network(self.net_g_ema, load_path, self.opt['path'].get('strict_load_g', True), 'params_ema')
+        else:
+            self.model_ema(0)  # copy net_g weight
+
+        self.net_g.train()
+        self.net_d.train()
+        self.net_g_ema.eval()
+
+        # define losses
+        # gan loss (wgan)
+        self.cri_gan = build_loss(train_opt['gan_opt']).to(self.device)
+        # regularization weights
+        self.r1_reg_weight = train_opt['r1_reg_weight']  # for discriminator
+        self.path_reg_weight = train_opt['path_reg_weight']  # for generator
+
+        self.net_g_reg_every = train_opt['net_g_reg_every']
+        self.net_d_reg_every = train_opt['net_d_reg_every']
+        self.mixing_prob = train_opt['mixing_prob']
+
+        self.mean_path_length = 0
+
+        # set up optimizers and schedulers
+        self.setup_optimizers()
+        self.setup_schedulers()
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        # optimizer g
+        net_g_reg_ratio = self.net_g_reg_every / (self.net_g_reg_every + 1)
+        if self.opt['network_g']['type'] == 'StyleGAN2GeneratorC':
+            normal_params = []
+            style_mlp_params = []
+            modulation_conv_params = []
+            for name, param in self.net_g.named_parameters():
+                if 'modulation' in name:
+                    normal_params.append(param)
+                elif 'style_mlp' in name:
+                    style_mlp_params.append(param)
+                elif 'modulated_conv' in name:
+                    modulation_conv_params.append(param)
+                else:
+                    normal_params.append(param)
+            optim_params_g = [
+                {  # add normal params first
+                    'params': normal_params,
+                    'lr': train_opt['optim_g']['lr']
+                },
+                {
+                    'params': style_mlp_params,
+                    'lr': train_opt['optim_g']['lr'] * 0.01
+                },
+                {
+                    'params': modulation_conv_params,
+                    'lr': train_opt['optim_g']['lr'] / 3
+                }
+            ]
+        else:
+            normal_params = []
+            for name, param in self.net_g.named_parameters():
+                normal_params.append(param)
+            optim_params_g = [{  # add normal params first
+                'params': normal_params,
+                'lr': train_opt['optim_g']['lr']
+            }]
+
+        optim_type = train_opt['optim_g'].pop('type')
+        lr = train_opt['optim_g']['lr'] * net_g_reg_ratio
+        betas = (0**net_g_reg_ratio, 0.99**net_g_reg_ratio)
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params_g, lr, betas=betas)
+        self.optimizers.append(self.optimizer_g)
+
+        # optimizer d
+        net_d_reg_ratio = self.net_d_reg_every / (self.net_d_reg_every + 1)
+        if self.opt['network_d']['type'] == 'StyleGAN2DiscriminatorC':
+            normal_params = []
+            linear_params = []
+            for name, param in self.net_d.named_parameters():
+                if 'final_linear' in name:
+                    linear_params.append(param)
+                else:
+                    normal_params.append(param)
+            optim_params_d = [
+                {  # add normal params first
+                    'params': normal_params,
+                    'lr': train_opt['optim_d']['lr']
+                },
+                {
+                    'params': linear_params,
+                    'lr': train_opt['optim_d']['lr'] * (1 / math.sqrt(512))
+                }
+            ]
+        else:
+            normal_params = []
+            for name, param in self.net_d.named_parameters():
+                normal_params.append(param)
+            optim_params_d = [{  # add normal params first
+                'params': normal_params,
+                'lr': train_opt['optim_d']['lr']
+            }]
+
+        optim_type = train_opt['optim_d'].pop('type')
+        lr = train_opt['optim_d']['lr'] * net_d_reg_ratio
+        betas = (0**net_d_reg_ratio, 0.99**net_d_reg_ratio)
+        self.optimizer_d = self.get_optimizer(optim_type, optim_params_d, lr, betas=betas)
+        self.optimizers.append(self.optimizer_d)
+
+    def feed_data(self, data):
+        self.real_img = data['gt'].to(self.device)
+
+    def make_noise(self, batch, num_noise):
+        if num_noise == 1:
+            noises = torch.randn(batch, self.num_style_feat, device=self.device)
+        else:
+            noises = torch.randn(num_noise, batch, self.num_style_feat, device=self.device).unbind(0)
+        return noises
+
+    def mixing_noise(self, batch, prob):
+        if random.random() < prob:
+            return self.make_noise(batch, 2)
+        else:
+            return [self.make_noise(batch, 1)]
+
+    def optimize_parameters(self, current_iter):
+        loss_dict = OrderedDict()
+
+        # optimize net_d
+        for p in self.net_d.parameters():
+            p.requires_grad = True
+        self.optimizer_d.zero_grad()
+
+        batch = self.real_img.size(0)
+        noise = self.mixing_noise(batch, self.mixing_prob)
+        fake_img, _ = self.net_g(noise)
+        fake_pred = self.net_d(fake_img.detach())
+
+        real_pred = self.net_d(self.real_img)
+        # wgan loss with softplus (logistic loss) for discriminator
+        l_d = self.cri_gan(real_pred, True, is_disc=True) + self.cri_gan(fake_pred, False, is_disc=True)
+        loss_dict['l_d'] = l_d
+        # In wgan, real_score should be positive and fake_score should be
+        # negative
+        loss_dict['real_score'] = real_pred.detach().mean()
+        loss_dict['fake_score'] = fake_pred.detach().mean()
+        l_d.backward()
+
+        if current_iter % self.net_d_reg_every == 0:
+            self.real_img.requires_grad = True
+            real_pred = self.net_d(self.real_img)
+            l_d_r1 = r1_penalty(real_pred, self.real_img)
+            l_d_r1 = (self.r1_reg_weight / 2 * l_d_r1 * self.net_d_reg_every + 0 * real_pred[0])
+            # TODO: why do we need to add 0 * real_pred, otherwise, a runtime
+            # error will arise: RuntimeError: Expected to have finished
+            # reduction in the prior iteration before starting a new one.
+            # This error indicates that your module has parameters that were
+            # not used in producing loss.
+            loss_dict['l_d_r1'] = l_d_r1.detach().mean()
+            l_d_r1.backward()
+
+        self.optimizer_d.step()
+
+        # optimize net_g
+        for p in self.net_d.parameters():
+            p.requires_grad = False
+        self.optimizer_g.zero_grad()
+
+        noise = self.mixing_noise(batch, self.mixing_prob)
+        fake_img, _ = self.net_g(noise)
+        fake_pred = self.net_d(fake_img)
+
+        # wgan loss with softplus (non-saturating loss) for generator
+        l_g = self.cri_gan(fake_pred, True, is_disc=False)
+        loss_dict['l_g'] = l_g
+        l_g.backward()
+
+        if current_iter % self.net_g_reg_every == 0:
+            path_batch_size = max(1, batch // self.opt['train']['path_batch_shrink'])
+            noise = self.mixing_noise(path_batch_size, self.mixing_prob)
+            fake_img, latents = self.net_g(noise, return_latents=True)
+            l_g_path, path_lengths, self.mean_path_length = g_path_regularize(fake_img, latents, self.mean_path_length)
+
+            l_g_path = (self.path_reg_weight * self.net_g_reg_every * l_g_path + 0 * fake_img[0, 0, 0, 0])
+            # TODO:  why do we need to add 0 * fake_img[0, 0, 0, 0]
+            l_g_path.backward()
+            loss_dict['l_g_path'] = l_g_path.detach().mean()
+            loss_dict['path_length'] = path_lengths
+
+        self.optimizer_g.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        # EMA
+        self.model_ema(decay=0.5**(32 / (10 * 1000)))
+
+    def test(self):
+        with torch.no_grad():
+            self.net_g_ema.eval()
+            self.output, _ = self.net_g_ema([self.fixed_sample])
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        if self.opt['rank'] == 0:
+            self.nondist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        assert dataloader is None, 'Validation dataloader should be None.'
+        self.test()
+        result = tensor2img(self.output, min_max=(-1, 1))
+        if self.opt['is_train']:
+            save_img_path = osp.join(self.opt['path']['visualization'], 'train', f'train_{current_iter}.png')
+        else:
+            save_img_path = osp.join(self.opt['path']['visualization'], 'test', f'test_{self.opt["name"]}.png')
+        imwrite(result, save_img_path)
+        # add sample images to tb_logger
+        result = (result / 255.).astype(np.float32)
+        result = cv2.cvtColor(result, cv2.COLOR_BGR2RGB)
+        if tb_logger is not None:
+            tb_logger.add_image('samples', result, global_step=current_iter, dataformats='HWC')
+
+    def save(self, epoch, current_iter):
+        self.save_network([self.net_g, self.net_g_ema], 'net_g', current_iter, param_key=['params', 'params_ema'])
+        self.save_network(self.net_d, 'net_d', current_iter)
+        self.save_training_state(epoch, current_iter)
diff --git a/r_basicsr/models/swinir_model.py b/r_basicsr/models/swinir_model.py
new file mode 100644
index 0000000..18e5550
--- /dev/null
+++ b/r_basicsr/models/swinir_model.py
@@ -0,0 +1,33 @@
+import torch
+from torch.nn import functional as F
+
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .sr_model import SRModel
+
+
+@MODEL_REGISTRY.register()
+class SwinIRModel(SRModel):
+
+    def test(self):
+        # pad to multiplication of window_size
+        window_size = self.opt['network_g']['window_size']
+        scale = self.opt.get('scale', 1)
+        mod_pad_h, mod_pad_w = 0, 0
+        _, _, h, w = self.lq.size()
+        if h % window_size != 0:
+            mod_pad_h = window_size - h % window_size
+        if w % window_size != 0:
+            mod_pad_w = window_size - w % window_size
+        img = F.pad(self.lq, (0, mod_pad_w, 0, mod_pad_h), 'reflect')
+        if hasattr(self, 'net_g_ema'):
+            self.net_g_ema.eval()
+            with torch.no_grad():
+                self.output = self.net_g_ema(img)
+        else:
+            self.net_g.eval()
+            with torch.no_grad():
+                self.output = self.net_g(img)
+            self.net_g.train()
+
+        _, _, h, w = self.output.size()
+        self.output = self.output[:, :, 0:h - mod_pad_h * scale, 0:w - mod_pad_w * scale]
diff --git a/r_basicsr/models/video_base_model.py b/r_basicsr/models/video_base_model.py
new file mode 100644
index 0000000..31ea37d
--- /dev/null
+++ b/r_basicsr/models/video_base_model.py
@@ -0,0 +1,160 @@
+import torch
+from collections import Counter
+from os import path as osp
+from torch import distributed as dist
+from tqdm import tqdm
+
+from r_basicsr.metrics import calculate_metric
+from r_basicsr.utils import get_root_logger, imwrite, tensor2img
+from r_basicsr.utils.dist_util import get_dist_info
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .sr_model import SRModel
+
+
+@MODEL_REGISTRY.register()
+class VideoBaseModel(SRModel):
+    """Base video SR model."""
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset = dataloader.dataset
+        dataset_name = dataset.opt['name']
+        with_metrics = self.opt['val']['metrics'] is not None
+        # initialize self.metric_results
+        # It is a dict: {
+        #    'folder1': tensor (num_frame x len(metrics)),
+        #    'folder2': tensor (num_frame x len(metrics))
+        # }
+        if with_metrics:
+            if not hasattr(self, 'metric_results'):  # only execute in the first run
+                self.metric_results = {}
+                num_frame_each_folder = Counter(dataset.data_info['folder'])
+                for folder, num_frame in num_frame_each_folder.items():
+                    self.metric_results[folder] = torch.zeros(
+                        num_frame, len(self.opt['val']['metrics']), dtype=torch.float32, device='cuda')
+            # initialize the best metric results
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        rank, world_size = get_dist_info()
+        if with_metrics:
+            for _, tensor in self.metric_results.items():
+                tensor.zero_()
+
+        metric_data = dict()
+        # record all frames (border and center frames)
+        if rank == 0:
+            pbar = tqdm(total=len(dataset), unit='frame')
+        for idx in range(rank, len(dataset), world_size):
+            val_data = dataset[idx]
+            val_data['lq'].unsqueeze_(0)
+            val_data['gt'].unsqueeze_(0)
+            folder = val_data['folder']
+            frame_idx, max_idx = val_data['idx'].split('/')
+            lq_path = val_data['lq_path']
+
+            self.feed_data(val_data)
+            self.test()
+            visuals = self.get_current_visuals()
+            result_img = tensor2img([visuals['result']])
+            metric_data['img'] = result_img
+            if 'gt' in visuals:
+                gt_img = tensor2img([visuals['gt']])
+                metric_data['img2'] = gt_img
+                del self.gt
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            torch.cuda.empty_cache()
+
+            if save_img:
+                if self.opt['is_train']:
+                    raise NotImplementedError('saving image is not supported during training.')
+                else:
+                    if 'vimeo' in dataset_name.lower():  # vimeo90k dataset
+                        split_result = lq_path.split('/')
+                        img_name = f'{split_result[-3]}_{split_result[-2]}_{split_result[-1].split(".")[0]}'
+                    else:  # other datasets, e.g., REDS, Vid4
+                        img_name = osp.splitext(osp.basename(lq_path))[0]
+
+                    if self.opt['val']['suffix']:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                 f'{img_name}_{self.opt["val"]["suffix"]}.png')
+                    else:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                 f'{img_name}_{self.opt["name"]}.png')
+                imwrite(result_img, save_img_path)
+
+            if with_metrics:
+                # calculate metrics
+                for metric_idx, opt_ in enumerate(self.opt['val']['metrics'].values()):
+                    result = calculate_metric(metric_data, opt_)
+                    self.metric_results[folder][int(frame_idx), metric_idx] += result
+
+            # progress bar
+            if rank == 0:
+                for _ in range(world_size):
+                    pbar.update(1)
+                    pbar.set_description(f'Test {folder}: {int(frame_idx) + world_size}/{max_idx}')
+        if rank == 0:
+            pbar.close()
+
+        if with_metrics:
+            if self.opt['dist']:
+                # collect data among GPUs
+                for _, tensor in self.metric_results.items():
+                    dist.reduce(tensor, 0)
+                dist.barrier()
+            else:
+                pass  # assume use one gpu in non-dist testing
+
+            if rank == 0:
+                self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        logger = get_root_logger()
+        logger.warning('nondist_validation is not implemented. Run dist_validation.')
+        self.dist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def _log_validation_metric_values(self, current_iter, dataset_name, tb_logger):
+        # ----------------- calculate the average values for each folder, and for each metric  ----------------- #
+        # average all frames for each sub-folder
+        # metric_results_avg is a dict:{
+        #    'folder1': tensor (len(metrics)),
+        #    'folder2': tensor (len(metrics))
+        # }
+        metric_results_avg = {
+            folder: torch.mean(tensor, dim=0).cpu()
+            for (folder, tensor) in self.metric_results.items()
+        }
+        # total_avg_results is a dict: {
+        #    'metric1': float,
+        #    'metric2': float
+        # }
+        total_avg_results = {metric: 0 for metric in self.opt['val']['metrics'].keys()}
+        for folder, tensor in metric_results_avg.items():
+            for idx, metric in enumerate(total_avg_results.keys()):
+                total_avg_results[metric] += metric_results_avg[folder][idx].item()
+        # average among folders
+        for metric in total_avg_results.keys():
+            total_avg_results[metric] /= len(metric_results_avg)
+            # update the best metric result
+            self._update_best_metric_result(dataset_name, metric, total_avg_results[metric], current_iter)
+
+        # ------------------------------------------ log the metric ------------------------------------------ #
+        log_str = f'Validation {dataset_name}\n'
+        for metric_idx, (metric, value) in enumerate(total_avg_results.items()):
+            log_str += f'\t # {metric}: {value:.4f}'
+            for folder, tensor in metric_results_avg.items():
+                log_str += f'\t # {folder}: {tensor[metric_idx].item():.4f}'
+            if hasattr(self, 'best_metric_results'):
+                log_str += (f'\n\t    Best: {self.best_metric_results[dataset_name][metric]["val"]:.4f} @ '
+                            f'{self.best_metric_results[dataset_name][metric]["iter"]} iter')
+            log_str += '\n'
+
+        logger = get_root_logger()
+        logger.info(log_str)
+        if tb_logger:
+            for metric_idx, (metric, value) in enumerate(total_avg_results.items()):
+                tb_logger.add_scalar(f'metrics/{metric}', value, current_iter)
+                for folder, tensor in metric_results_avg.items():
+                    tb_logger.add_scalar(f'metrics/{metric}/{folder}', tensor[metric_idx].item(), current_iter)
diff --git a/r_basicsr/models/video_gan_model.py b/r_basicsr/models/video_gan_model.py
new file mode 100644
index 0000000..cc44476
--- /dev/null
+++ b/r_basicsr/models/video_gan_model.py
@@ -0,0 +1,17 @@
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .srgan_model import SRGANModel
+from .video_base_model import VideoBaseModel
+
+
+@MODEL_REGISTRY.register()
+class VideoGANModel(SRGANModel, VideoBaseModel):
+    """Video GAN model.
+
+    Use multiple inheritance.
+    It will first use the functions of SRGANModel:
+        init_training_settings
+        setup_optimizers
+        optimize_parameters
+        save
+    Then find functions in VideoBaseModel.
+    """
diff --git a/r_basicsr/models/video_recurrent_gan_model.py b/r_basicsr/models/video_recurrent_gan_model.py
new file mode 100644
index 0000000..2800e27
--- /dev/null
+++ b/r_basicsr/models/video_recurrent_gan_model.py
@@ -0,0 +1,180 @@
+import torch
+from collections import OrderedDict
+
+from r_basicsr.archs import build_network
+from r_basicsr.losses import build_loss
+from r_basicsr.utils import get_root_logger
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .video_recurrent_model import VideoRecurrentModel
+
+
+@MODEL_REGISTRY.register()
+class VideoRecurrentGANModel(VideoRecurrentModel):
+
+    def init_training_settings(self):
+        train_opt = self.opt['train']
+
+        self.ema_decay = train_opt.get('ema_decay', 0)
+        if self.ema_decay > 0:
+            logger = get_root_logger()
+            logger.info(f'Use Exponential Moving Average with decay: {self.ema_decay}')
+            # build network net_g with Exponential Moving Average (EMA)
+            # net_g_ema only used for testing on one GPU and saving.
+            # There is no need to wrap with DistributedDataParallel
+            self.net_g_ema = build_network(self.opt['network_g']).to(self.device)
+            # load pretrained model
+            load_path = self.opt['path'].get('pretrain_network_g', None)
+            if load_path is not None:
+                self.load_network(self.net_g_ema, load_path, self.opt['path'].get('strict_load_g', True), 'params_ema')
+            else:
+                self.model_ema(0)  # copy net_g weight
+            self.net_g_ema.eval()
+
+        # define network net_d
+        self.net_d = build_network(self.opt['network_d'])
+        self.net_d = self.model_to_device(self.net_d)
+        self.print_network(self.net_d)
+
+        # load pretrained models
+        load_path = self.opt['path'].get('pretrain_network_d', None)
+        if load_path is not None:
+            param_key = self.opt['path'].get('param_key_d', 'params')
+            self.load_network(self.net_d, load_path, self.opt['path'].get('strict_load_d', True), param_key)
+
+        self.net_g.train()
+        self.net_d.train()
+
+        # define losses
+        if train_opt.get('pixel_opt'):
+            self.cri_pix = build_loss(train_opt['pixel_opt']).to(self.device)
+        else:
+            self.cri_pix = None
+
+        if train_opt.get('perceptual_opt'):
+            self.cri_perceptual = build_loss(train_opt['perceptual_opt']).to(self.device)
+        else:
+            self.cri_perceptual = None
+
+        if train_opt.get('gan_opt'):
+            self.cri_gan = build_loss(train_opt['gan_opt']).to(self.device)
+
+        self.net_d_iters = train_opt.get('net_d_iters', 1)
+        self.net_d_init_iters = train_opt.get('net_d_init_iters', 0)
+
+        # set up optimizers and schedulers
+        self.setup_optimizers()
+        self.setup_schedulers()
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        if train_opt['fix_flow']:
+            normal_params = []
+            flow_params = []
+            for name, param in self.net_g.named_parameters():
+                if 'spynet' in name:  # The fix_flow now only works for spynet.
+                    flow_params.append(param)
+                else:
+                    normal_params.append(param)
+
+            optim_params = [
+                {  # add flow params first
+                    'params': flow_params,
+                    'lr': train_opt['lr_flow']
+                },
+                {
+                    'params': normal_params,
+                    'lr': train_opt['optim_g']['lr']
+                },
+            ]
+        else:
+            optim_params = self.net_g.parameters()
+
+        # optimizer g
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+        # optimizer d
+        optim_type = train_opt['optim_d'].pop('type')
+        self.optimizer_d = self.get_optimizer(optim_type, self.net_d.parameters(), **train_opt['optim_d'])
+        self.optimizers.append(self.optimizer_d)
+
+    def optimize_parameters(self, current_iter):
+        logger = get_root_logger()
+        # optimize net_g
+        for p in self.net_d.parameters():
+            p.requires_grad = False
+
+        if self.fix_flow_iter:
+            if current_iter == 1:
+                logger.info(f'Fix flow network and feature extractor for {self.fix_flow_iter} iters.')
+                for name, param in self.net_g.named_parameters():
+                    if 'spynet' in name or 'edvr' in name:
+                        param.requires_grad_(False)
+            elif current_iter == self.fix_flow_iter:
+                logger.warning('Train all the parameters.')
+                self.net_g.requires_grad_(True)
+
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+
+        _, _, c, h, w = self.output.size()
+
+        l_g_total = 0
+        loss_dict = OrderedDict()
+        if (current_iter % self.net_d_iters == 0 and current_iter > self.net_d_init_iters):
+            # pixel loss
+            if self.cri_pix:
+                l_g_pix = self.cri_pix(self.output, self.gt)
+                l_g_total += l_g_pix
+                loss_dict['l_g_pix'] = l_g_pix
+            # perceptual loss
+            if self.cri_perceptual:
+                l_g_percep, l_g_style = self.cri_perceptual(self.output.view(-1, c, h, w), self.gt.view(-1, c, h, w))
+                if l_g_percep is not None:
+                    l_g_total += l_g_percep
+                    loss_dict['l_g_percep'] = l_g_percep
+                if l_g_style is not None:
+                    l_g_total += l_g_style
+                    loss_dict['l_g_style'] = l_g_style
+            # gan loss
+            fake_g_pred = self.net_d(self.output.view(-1, c, h, w))
+            l_g_gan = self.cri_gan(fake_g_pred, True, is_disc=False)
+            l_g_total += l_g_gan
+            loss_dict['l_g_gan'] = l_g_gan
+
+            l_g_total.backward()
+            self.optimizer_g.step()
+
+        # optimize net_d
+        for p in self.net_d.parameters():
+            p.requires_grad = True
+
+        self.optimizer_d.zero_grad()
+        # real
+        # reshape to (b*n, c, h, w)
+        real_d_pred = self.net_d(self.gt.view(-1, c, h, w))
+        l_d_real = self.cri_gan(real_d_pred, True, is_disc=True)
+        loss_dict['l_d_real'] = l_d_real
+        loss_dict['out_d_real'] = torch.mean(real_d_pred.detach())
+        l_d_real.backward()
+        # fake
+        # reshape to (b*n, c, h, w)
+        fake_d_pred = self.net_d(self.output.view(-1, c, h, w).detach())
+        l_d_fake = self.cri_gan(fake_d_pred, False, is_disc=True)
+        loss_dict['l_d_fake'] = l_d_fake
+        loss_dict['out_d_fake'] = torch.mean(fake_d_pred.detach())
+        l_d_fake.backward()
+        self.optimizer_d.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
+
+    def save(self, epoch, current_iter):
+        if self.ema_decay > 0:
+            self.save_network([self.net_g, self.net_g_ema], 'net_g', current_iter, param_key=['params', 'params_ema'])
+        else:
+            self.save_network(self.net_g, 'net_g', current_iter)
+        self.save_network(self.net_d, 'net_d', current_iter)
+        self.save_training_state(epoch, current_iter)
diff --git a/r_basicsr/models/video_recurrent_model.py b/r_basicsr/models/video_recurrent_model.py
new file mode 100644
index 0000000..ea3a4c5
--- /dev/null
+++ b/r_basicsr/models/video_recurrent_model.py
@@ -0,0 +1,197 @@
+import torch
+from collections import Counter
+from os import path as osp
+from torch import distributed as dist
+from tqdm import tqdm
+
+from r_basicsr.metrics import calculate_metric
+from r_basicsr.utils import get_root_logger, imwrite, tensor2img
+from r_basicsr.utils.dist_util import get_dist_info
+from r_basicsr.utils.registry import MODEL_REGISTRY
+from .video_base_model import VideoBaseModel
+
+
+@MODEL_REGISTRY.register()
+class VideoRecurrentModel(VideoBaseModel):
+
+    def __init__(self, opt):
+        super(VideoRecurrentModel, self).__init__(opt)
+        if self.is_train:
+            self.fix_flow_iter = opt['train'].get('fix_flow')
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        flow_lr_mul = train_opt.get('flow_lr_mul', 1)
+        logger = get_root_logger()
+        logger.info(f'Multiple the learning rate for flow network with {flow_lr_mul}.')
+        if flow_lr_mul == 1:
+            optim_params = self.net_g.parameters()
+        else:  # separate flow params and normal params for different lr
+            normal_params = []
+            flow_params = []
+            for name, param in self.net_g.named_parameters():
+                if 'spynet' in name:
+                    flow_params.append(param)
+                else:
+                    normal_params.append(param)
+            optim_params = [
+                {  # add normal params first
+                    'params': normal_params,
+                    'lr': train_opt['optim_g']['lr']
+                },
+                {
+                    'params': flow_params,
+                    'lr': train_opt['optim_g']['lr'] * flow_lr_mul
+                },
+            ]
+
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+
+    def optimize_parameters(self, current_iter):
+        if self.fix_flow_iter:
+            logger = get_root_logger()
+            if current_iter == 1:
+                logger.info(f'Fix flow network and feature extractor for {self.fix_flow_iter} iters.')
+                for name, param in self.net_g.named_parameters():
+                    if 'spynet' in name or 'edvr' in name:
+                        param.requires_grad_(False)
+            elif current_iter == self.fix_flow_iter:
+                logger.warning('Train all the parameters.')
+                self.net_g.requires_grad_(True)
+
+        super(VideoRecurrentModel, self).optimize_parameters(current_iter)
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset = dataloader.dataset
+        dataset_name = dataset.opt['name']
+        with_metrics = self.opt['val']['metrics'] is not None
+        # initialize self.metric_results
+        # It is a dict: {
+        #    'folder1': tensor (num_frame x len(metrics)),
+        #    'folder2': tensor (num_frame x len(metrics))
+        # }
+        if with_metrics:
+            if not hasattr(self, 'metric_results'):  # only execute in the first run
+                self.metric_results = {}
+                num_frame_each_folder = Counter(dataset.data_info['folder'])
+                for folder, num_frame in num_frame_each_folder.items():
+                    self.metric_results[folder] = torch.zeros(
+                        num_frame, len(self.opt['val']['metrics']), dtype=torch.float32, device='cuda')
+            # initialize the best metric results
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        rank, world_size = get_dist_info()
+        if with_metrics:
+            for _, tensor in self.metric_results.items():
+                tensor.zero_()
+
+        metric_data = dict()
+        num_folders = len(dataset)
+        num_pad = (world_size - (num_folders % world_size)) % world_size
+        if rank == 0:
+            pbar = tqdm(total=len(dataset), unit='folder')
+        # Will evaluate (num_folders + num_pad) times, but only the first num_folders results will be recorded.
+        # (To avoid wait-dead)
+        for i in range(rank, num_folders + num_pad, world_size):
+            idx = min(i, num_folders - 1)
+            val_data = dataset[idx]
+            folder = val_data['folder']
+
+            # compute outputs
+            val_data['lq'].unsqueeze_(0)
+            val_data['gt'].unsqueeze_(0)
+            self.feed_data(val_data)
+            val_data['lq'].squeeze_(0)
+            val_data['gt'].squeeze_(0)
+
+            self.test()
+            visuals = self.get_current_visuals()
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            if 'gt' in visuals:
+                del self.gt
+            torch.cuda.empty_cache()
+
+            if self.center_frame_only:
+                visuals['result'] = visuals['result'].unsqueeze(1)
+                if 'gt' in visuals:
+                    visuals['gt'] = visuals['gt'].unsqueeze(1)
+
+            # evaluate
+            if i < num_folders:
+                for idx in range(visuals['result'].size(1)):
+                    result = visuals['result'][0, idx, :, :, :]
+                    result_img = tensor2img([result])  # uint8, bgr
+                    metric_data['img'] = result_img
+                    if 'gt' in visuals:
+                        gt = visuals['gt'][0, idx, :, :, :]
+                        gt_img = tensor2img([gt])  # uint8, bgr
+                        metric_data['img2'] = gt_img
+
+                    if save_img:
+                        if self.opt['is_train']:
+                            raise NotImplementedError('saving image is not supported during training.')
+                        else:
+                            if self.center_frame_only:  # vimeo-90k
+                                clip_ = val_data['lq_path'].split('/')[-3]
+                                seq_ = val_data['lq_path'].split('/')[-2]
+                                name_ = f'{clip_}_{seq_}'
+                                img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                    f"{name_}_{self.opt['name']}.png")
+                            else:  # others
+                                img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                    f"{idx:08d}_{self.opt['name']}.png")
+                            # image name only for REDS dataset
+                        imwrite(result_img, img_path)
+
+                    # calculate metrics
+                    if with_metrics:
+                        for metric_idx, opt_ in enumerate(self.opt['val']['metrics'].values()):
+                            result = calculate_metric(metric_data, opt_)
+                            self.metric_results[folder][idx, metric_idx] += result
+
+                # progress bar
+                if rank == 0:
+                    for _ in range(world_size):
+                        pbar.update(1)
+                        pbar.set_description(f'Folder: {folder}')
+
+        if rank == 0:
+            pbar.close()
+
+        if with_metrics:
+            if self.opt['dist']:
+                # collect data among GPUs
+                for _, tensor in self.metric_results.items():
+                    dist.reduce(tensor, 0)
+                dist.barrier()
+
+            if rank == 0:
+                self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def test(self):
+        n = self.lq.size(1)
+        self.net_g.eval()
+
+        flip_seq = self.opt['val'].get('flip_seq', False)
+        self.center_frame_only = self.opt['val'].get('center_frame_only', False)
+
+        if flip_seq:
+            self.lq = torch.cat([self.lq, self.lq.flip(1)], dim=1)
+
+        with torch.no_grad():
+            self.output = self.net_g(self.lq)
+
+        if flip_seq:
+            output_1 = self.output[:, :n, :, :, :]
+            output_2 = self.output[:, n:, :, :, :].flip(1)
+            self.output = 0.5 * (output_1 + output_2)
+
+        if self.center_frame_only:
+            self.output = self.output[:, n // 2, :, :, :]
+
+        self.net_g.train()
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