This has been discussed before, but my question is a bit different. Lets say have a video file with 1+2 as stereo. Now I want to add 3-8 with silent audio - most likely using the anullsrc. I need to map that generator to only affect channel 3-8. Anyone has a solution for that?
1 Answers
No need for a source filter. Just need pan.
ffmpeg -i input -af "pan=8C|c0=c0|c1=c1" -c:v copy out
The first two output channels have their maps set to the two input channels. Since the other 6 are omitted, they will be mute.
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