mmagic.models.editors.basicvsr_plusplus_net.basicvsr_plusplus_net

Module Contents

Classes

BasicVSRPlusPlusNet	BasicVSR++ network structure.
SecondOrderDeformableAlignment	Second-order deformable alignment module.

class mmagic.models.editors.basicvsr_plusplus_net.basicvsr_plusplus_net.BasicVSRPlusPlusNet(mid_channels=64, num_blocks=7, max_residue_magnitude=10, is_low_res_input=True, spynet_pretrained=None, cpu_cache_length=100)

Bases: mmengine.model.BaseModule

BasicVSR++ network structure.

Support either x4 upsampling or same size output.

Paper:

BasicVSR++: Improving Video Super-Resolution with Enhanced Propagation and Alignment

参数

• mid_channels (int, optional) – Channel number of the intermediate features. Default: 64.

• num_blocks (int, optional) – The number of residual blocks in each propagation branch. Default: 7.

• max_residue_magnitude (int) – The maximum magnitude of the offset residue (Eq. 6 in paper). Default: 10.

• is_low_res_input (bool, optional) – Whether the input is low-resolution or not. If False, the output resolution is equal to the input resolution. Default: True.

• spynet_pretrained (str, optional) – Pre-trained model path of SPyNet. Default: None.

• cpu_cache_length (int, optional) – When the length of sequence is larger than this value, the intermediate features are sent to CPU. This saves GPU memory, but slows down the inference speed. You can increase this number if you have a GPU with large memory. Default: 100.

check_if_mirror_extended(lqs)

Check whether the input is a mirror-extended sequence.

If mirror-extended, the i-th (i=0, …, t-1) frame is equal to the (t-1-i)-th frame.

参数

lqs (tensor) – Input low quality (LQ) sequence with shape (n, t, c, h, w).

compute_flow(lqs)

Compute optical flow using SPyNet for feature alignment.

Note that if the input is an mirror-extended sequence, ‘flows_forward’ is not needed, since it is equal to ‘flows_backward.flip(1)’.

参数

lqs (tensor) – Input low quality (LQ) sequence with shape (n, t, c, h, w).

返回

Optical flow. ‘flows_forward’ corresponds to the

flows used for forward-time propagation (current to previous). ‘flows_backward’ corresponds to the flows used for backward-time propagation (current to next).

返回类型

tuple(Tensor)

propagate(feats, flows, module_name)

Propagate the latent features throughout the sequence.

参数

• dict (feats) – Features from previous branches. Each component is a list of tensors with shape (n, c, h, w).

• flows (tensor) – Optical flows with shape (n, t - 1, 2, h, w).

• module_name (str) – The name of the propagation branches. Can either be ‘backward_1’, ‘forward_1’, ‘backward_2’, ‘forward_2’.

返回

A dictionary containing all the propagated

features. Each key in the dictionary corresponds to a propagation branch, which is represented by a list of tensors.

返回类型

dict(list[tensor])

upsample(lqs, feats)

Compute the output image given the features.

参数

• lqs (tensor) – Input low quality (LQ) sequence with shape (n, t, c, h, w).

• feats (dict) – The features from the propagation branches.

返回

Output HR sequence with shape (n, t, c, 4h, 4w).

返回类型

Tensor

forward(lqs)

Forward function for BasicVSR++.

参数

lqs (tensor) – Input low quality (LQ) sequence with shape (n, t, c, h, w).

返回

Output HR sequence with shape (n, t, c, 4h, 4w).

返回类型

Tensor

class mmagic.models.editors.basicvsr_plusplus_net.basicvsr_plusplus_net.SecondOrderDeformableAlignment(*args, **kwargs)

Bases: mmcv.ops.ModulatedDeformConv2d

Second-order deformable alignment module.

参数

• in_channels (int) – Same as nn.Conv2d.

• out_channels (int) – Same as nn.Conv2d.

• kernel_size (int or tuple[int]) – Same as nn.Conv2d.

• stride (int or tuple[int]) – Same as nn.Conv2d.

• padding (int or tuple[int]) – Same as nn.Conv2d.

• dilation (int or tuple[int]) – Same as nn.Conv2d.

• groups (int) – Same as nn.Conv2d.

• bias (bool or str) – If specified as auto, it will be decided by the norm_cfg. Bias will be set as True if norm_cfg is None, otherwise False.

• max_residue_magnitude (int) – The maximum magnitude of the offset residue (Eq. 6 in paper). Default: 10.

init_offset()

Init constant offset.

forward(x, extra_feat, flow_1, flow_2)

Forward function.