ffmpeg: 视频剪切和拼接

def cut_and_stitch(input_video, time_list, output_video):
    """
    剪切掉所有time_list里的片段,将其余片段拼接起来
    """

    all_cut = []
    filter_cmd = []
    for i, (start, end) in enumerate(time_list):
        filter_cmd.append(
            '[0:v] trim=start={}:end={},setpts=PTS-STARTPTS,format=yuv420p [{}v];'.format(start, end, i))
        filter_cmd.append('[0:a] atrim=start={}:end={},asetpts=PTS-STARTPTS [{}a];'.format(start, end, i))
        all_cut.append('[{}v][{}a]'.format(i, i))
    cmd = "ffmpeg -i {} -filter_complex '{} concat=n={}:v=1:a=1[outv][outa]' -map [outv] -map [outa] -q:v 5 {}".format(
        input_video, ' '.join(filter_cmd) + ''.join(all_cut), len(all_cut), output_video)
    print('cmd:', cmd)
    os.system(cmd)