python av视频库使用方式

python av视频库使用方式

class VideoReader:
    def __init__(self, source_path, step=1, start=0, stop=None, dimension=DimensionType.DIM_2D):
        super().__init__(
            source_path=source_path,
            step=step,
            start=start,
            stop=stop + 1 if stop is not None else stop,
            dimension=dimension,
        )

    def _has_frame(self, i):
        if i >= self._start:
            if (i - self._start) % self._step == 0:
                if self._stop is None or i < self._stop:
                    return True

        return False

    def _decode(self, container):
        frame_num = 0
        for packet in container.demux():
            if packet.stream.type == 'video':
                for image in packet.decode():
                    frame_num += 1
                    if self._has_frame(frame_num - 1):
                        if packet.stream.metadata.get('rotate'):
                            old_image = image
                            image = av.Videoframe().from_ndarray(
                                rotate_image(
                                    image.to_ndarray(format='bgr24'),
                                    360 - int(container.streams.video[0].metadata.get('rotate'))
                                ),
                                format ='bgr24'
                            )
                            image.pts = old_image.pts
                        yield (image, self._source_path[0], image.pts)

    def __iter__(self):
        container = self._get_av_container()
        source_video_stream = container.streams.video[0]
        source_video_stream.thread_type = 'AUTO'

        return self._decode(container)

    def get_progress(self, pos):
        container = self._get_av_container()
        # Not for all containers return real value
        stream = container.streams.video[0]
        return pos / stream.duration if stream.duration else None

    def _get_av_container(self):
        if isinstance(self._source_path[0], io.BytesIO):
            self._source_path[0].seek(0) # required for re-reading
        return av.open(self._source_path[0])

    def get_preview(self):
        container = self._get_av_container()
        stream = container.streams.video[0]
        preview = next(container.decode(stream))
        return self._get_preview(preview.to_image() if not stream.metadata.get('rotate') 
            else av.Videoframe().from_ndarray(
                rotate_image(
                    preview.to_ndarray(format='bgr24'),
                    360 - int(container.streams.video[0].metadata.get('rotate'))
                ),
                format ='bgr24'
            ).to_image()
        )

    def get_image_size(self, i):
        image = (next(iter(self)))[0]
        return image.width, image.height

官网PyAV documentation — PyAV 8.0.1 documentation