import av
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import os
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import pims
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import numpy as np
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from torch.utils.data import Dataset
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from torchvision.transforms.functional import to_pil_image
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from PIL import Image
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class VideoReader(Dataset):
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def __init__(self, path, transform=None):
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self.video = pims.PyAVVideoReader(path)
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self.rate = self.video.frame_rate
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self.transform = transform
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@property
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def frame_rate(self):
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return self.rate
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def __len__(self):
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return len(self.video)
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def __getitem__(self, idx):
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frame = self.video[idx]
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frame = Image.fromarray(np.asarray(frame))
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if self.transform is not None:
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frame = self.transform(frame)
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return frame
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class VideoWriter:
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def __init__(self, path, frame_rate, bit_rate=1000000):
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self.container = av.open(path, mode='w')
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self.stream = self.container.add_stream('h264', rate=round(frame_rate))
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self.stream.pix_fmt = 'yuv420p'
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self.stream.bit_rate = bit_rate
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self.stream.codec_context.options = {
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'crf': '18', # 控制画质，越小越清晰（18是高质量）
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'preset': 'veryfast', # 影响编码速度，medium 是1x，fast是2x faster是3x veryfast是4x superfast是6x ultrafast是10x，文件体积大约会增加(以medium为基准) 10%，15%，20% 30% 50%
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'tune': 'film',
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}
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def write(self, frames):
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# frames: [T, C, H, W]
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self.stream.width = frames.size(3)
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self.stream.height = frames.size(2)
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if frames.size(1) == 1:
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frames = frames.repeat(1, 3, 1, 1) # convert grayscale to RGB
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frames = frames.mul(255).byte().cpu().permute(0, 2, 3, 1).numpy()
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for t in range(frames.shape[0]):
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frame = frames[t]
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frame = av.VideoFrame.from_ndarray(frame, format='rgb24')
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self.container.mux(self.stream.encode(frame))
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def close(self):
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self.container.mux(self.stream.encode())
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self.container.close()
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class ImageSequenceReader(Dataset):
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def __init__(self, path, transform=None):
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self.path = path
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self.files = sorted(os.listdir(path))
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self.transform = transform
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def __len__(self):
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return len(self.files)
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def __getitem__(self, idx):
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with Image.open(os.path.join(self.path, self.files[idx])) as img:
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img.load()
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if self.transform is not None:
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return self.transform(img)
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return img
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class ImageSequenceWriter:
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def __init__(self, path, extension='jpg'):
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self.path = path
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self.extension = extension
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self.counter = 0
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os.makedirs(path, exist_ok=True)
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def write(self, frames):
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# frames: [T, C, H, W]
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for t in range(frames.shape[0]):
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to_pil_image(frames[t]).save(os.path.join(
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self.path, str(self.counter).zfill(4) + '.' + self.extension))
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self.counter += 1
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def close(self):
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pass
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