使用 filter_complex 时如何使用 ffmpeg 修剪视频？

Question

I am using a complex_filter with ffmpeg to join multiple video-files.

ffmpeg -i video1.webm -i video2.webm -v debug -strict -2 -filter_complex "[0:v] [0:a:0] [1:v] [1:a:0] concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4

This is working for me. But now i want to select a start and an endpoint for EACH input video, so that i can cut each of the videos.

I already tried

ffmpeg -i video1.webm -ss 00:00:01.000 -t 00:00:05.658 -i video2.webm -ss 00:00:01.000 -t 00:00:05.658 -v debug -strict -2 -filter_complex "[0:v] [0:a:0] [1:v] [1:a:0] concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4

But that wasn't working as expected. also the -to parameter is not working.

Is it possible to do this with a complex filter?

Answer 1

John Carmack of Oculus says that you can use this ( https://mediamachine.io/blog/ffmpeg-series-complex-filters-trim-concat/ ):

ffmpeg \
-i "$INPUT_FILE_1" \
-i "$INPUT_FILE_2" \
-i "$INPUT_FILE_3" \
-filter_complex \
"[0:v]trim=start=5:duration=10,setpts=PTS-STARTPTS[v0]; \
 [0:a]atrim=start=5:duration=10,asetpts=PTS-STARTPTS[a0]; \
 [1:v]trim=start=20:duration=10,setpts=PTS-STARTPTS[v1];
 [1:a]atrim=start=20:duration=10,asetpts=PTS-STARTPTS[a1]; \
 [2:v]trim=start=20:duration=10,setpts=PTS-STARTPTS[v2];
 [2:a]atrim=start=20:duration=10,asetpts=PTS-STARTPTS[a2]; \
 [v0][a0][v1][a1][v2][a2]concat=n=3:v=1:a=1[final]" \
-map "[final]" concat-video.mp4

So, for your example

ffmpeg -i video1.webm -i video2.webm  -v debug -strict -2
-filter_complex 
"[0:v]trim=start=1:duration=4.658[v0]
[0:a:0]atrim=start=1:duration=4.658[a0]
[1:v]trim=start=1:duration=4.658[v1]
[1:a:0]atrim=start=1:duration=4.658[a1]
[v0][a0][v1][a1]concat=n=2:v=1:a=1[v][a]"
-map "[v]" -map "[a]" output.mp4

I'm pretty sure you only need the setpts stuff if your videos are trimmed from different starting locations.