python - ffmpeg-python 修剪和连接不起作用

Question

我有两个文件，in.mp4 和 outro.mp4。

我需要一个非常简单的事情:将 in.mp4 修剪为任意长度，并在其后连接 outro.mp4。

我可以在没有修剪部分的情况下做到这一点

import ffmpeg

main_video = ffmpeg.input('in.mp4')
outro = ffmpeg.input('outro.mp4')

v1 = main_video.video.filter("scale", size='hd720')
a1 = main_video.audio
v2 = outro.video
a2 = outro.audio

joined = ffmpeg.concat(v1, a1, v2, a2, v=1, a=1).node
v3 = joined[0]
a3 = joined[1]

out = ffmpeg.output(v3, a3, 'out.mp4')
out.run()

但是如果我在这里添加修剪:

main_video = ffmpeg.input('in.mp4').trim(start_frame=0, end_frame=1000)

我收到此错误:

ValueError: Encountered trim(end_frame=1000, start_frame=0) <17c7b86357ec> with multiple outgoing edges with same upstream label None; a split filter is probably required

如果我尝试在这里这样做:

v1 = main_video.video.filter("scale", size='hd720').trim(start_frame=0, end_frame=1000)
a1 = main_video.audio.trim(start_frame=0, end_frame=1000)

我收到这些错误:

[Parsed_trim_2 @ 00000295587ca840] Media type mismatch between the 'Parsed_trim_2' filter output pad 0 (video) and the 'Parsed_concat_3' filter input pad 1 (audio)
[AVFilterGraph @ 00000295587cc800] Cannot create the link trim:0 -> concat:1

我该如何解决这个问题？

Answer 1

您可以对视频使用trim过滤器，对音频使用atrim过滤器，并将两者剪切持续时间:

import ffmpeg
#import subprocess

# Build synthetic video files (with audio):
##############################################################
# subprocess.run('ffmpeg -y -f lavfi -i testsrc=size=1280x720:rate=30 -f lavfi -i sine=frequency=500 -c:v libx264 -c:a ac3 -ar 22050 -t 100 in.mp4')
# subprocess.run('ffmpeg -y -f lavfi -i mandelbrot=size=1280x720:rate=30 -f lavfi -i sine=frequency=1000 -c:v libx264 -c:a ac3 -ar 22050 -t 10 outro.mp4')
##############################################################


main_video = ffmpeg.input('in.mp4')
outro = ffmpeg.input('outro.mp4')

# Assuming frame rate is 30 fps, 33.3 seconds applies 1000 frames.
v1 = main_video.video.filter('scale', size='hd720').filter('trim', duration=33.3)  # Use trim filter for the video.
a1 = main_video.audio.filter('atrim', duration=33.3) # Use atrim filter for the audio.
v2 = outro.video
a2 = outro.audio

joined = ffmpeg.concat(v1, a1, v2, a2, v=1, a=1).node
v3 = joined[0]
a3 = joined[1]

out = ffmpeg.output(v3, a3, 'out.mp4')
out.run()

我通过生成合成视频文件(在注释部分生成)来测试上面的代码。