I have two videos from two GoPro cameras. Both videos are rendered via ffmpeg side-by-side into a single video (left and right) and the audio is currently combined/mixed into two channels (stereo). I can hear both camera audio channels at the same time.
Two channels stereo:
ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]; [0:a][1:a]amerge[a]" -map "[v]" -map "[a]" -ac 2 side-by-side.mp4
audio from both videos mixed into a single file with 2 channels - mediainfo
Now I want to switch between the two audio channels (cam1 or cam2) while I'm playing the side-by-side video.
My first try: With four channels (without -ac 2 parameter):
ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]; [0:a][1:a]amerge[a]" -map "[v]" -map "[a]" side-by-side.mp4
audio from both videos mixed into a single file with 4 channels - mediainfo
But the most video players can't easily select the channels 1+2 or 3+4 while playing.
So I tried two languages:
ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]; [0:a][1:a]amerge[a]" -map "[v]" -map "[a]" -metadata:s:a:0 language=ger -metadata:s:a:1 language=eng side-by-side.mp4
audio from both videos mixed into a single file with 4 channels with languages - mediainfo
But that's wrong. I can only see german with 4 channels. How can I put channels 1+2 into german and channels 3+4 into english? Afterwards I should be able to use the multi language feature from most video players to switch the audio between cameras.
Thank you,
Miriam
This worked for me
ffmpeg -i Video1.mp4 -i Video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]" -map [v] -map 0:a:0 -map 1:a:0 -metadata:s:a:0 language=ger -metadata:s:a:1 language=eng output.mp4
With this you should be able to switch between the audios