使用moviepy包（Python）的问题答案

【问题标题】：Issue using moviepy package (Python)使用moviepy包（Python）的问题
【发布时间】：2021-01-03 16:14:46
【问题描述】：

我正在使用来自 moviepy 的 ffmpeg_extract_subclip 函数来处理视频文件。但是，我得到的视频剪辑与我设置的开始时间和结束时间之间的长度不同。例如写作：

from moviepy.video.io.ffmpeg_tools import ffmpeg_extract_subclip

clip=clip_filename
cutclip="cutvideo.avi"
ffmpeg_extract_subclip(clip_filename, 0, 10, targetname=cutclip)

我得到一个长度为 10,03 或类似长度的视频（就帧数而言，我得到 602 帧而不是正好 600 帧）。有没有办法获得更准确的输出？

【问题讨论】：

标签： python python-3.x ffmpeg video-processing video-editing

【解决方案1】：

嗯...我会合并this 答案和ffmpeg_extract_subclip(https://zulko.github.io/moviepy/_modules/moviepy/video/io/ffmpeg_tools.html#ffmpeg_extract_subclip) 的实际实现：

def ffmpeg_extract_subclip(filename, t1, t2, targetname=None):
        """ Makes a new video file playing video file ``filename`` between
        the times ``t1`` and ``t2``. """
    name, ext = os.path.splitext(filename)
    if not targetname:
        T1, T2 = [int(1000*t) for t in [t1, t2]]
        targetname = "%sSUB%d_%d.%s" % (name, T1, T2, ext)
    
    cmd = [get_setting("FFMPEG_BINARY"),"-y",
           "-ss", "%0.2f"%t1,
           "-i", filename,
           "-t", "%0.2f"%(t2-t1),
           "-map", "0", "-vcodec", "copy", "-acodec", "copy", targetname]
    
    subprocess_call(cmd)

因此，如您所见，该库是无状态的，因此可以轻松扩展：

def ffmpeg_extract_subclip_precisely(filename, t1, t2, targetname=None):
    """ Makes a new video file playing video file ``filename`` between
        the times ``t1`` and ``t2``. """
    name, ext = os.path.splitext(filename)
    if not targetname:
        T1, T2 = [int(1000*t) for t in [t1, t2]]
        targetname = "%sSUB%d_%d.%s" % (name, T1, T2, ext)

    cmd = [get_setting("FFMPEG_BINARY"), "-i", filename,
           "-force_key_frames", "{}:{}".format(t1,t2), "temp_out.mp4"]

    subprocess_call(cmd)
    
    cmd = [get_setting("FFMPEG_BINARY"),"-y",
           "-ss", "%0.2f"%t1,
           "-i", "temp_out.mp4",
           "-t", "%0.2f"%(t2-t1),
           "-map", "0", "-vcodec", "copy", "-acodec", "copy", targetname]
    
    subprocess_call(cmd)

顺便说一下，我认为您应该尽可能以毫秒精度指定时间。

请注意以上代码未经测试。

【讨论】：