[FFmpeg-user] Video with Multi-channel audio, How to Stream?

[Karl E. Fitzke]

Hello, I am creating derivative files from a number of videos captured as one stream of four channels, but which only one pair (1&2 or 3&4) should really play at any given time.  I imagined that restreaming 1 stream of four channels to two stereo streams was the way to go, but now I'm second guessing myself having encountered at least one situation where those two streams seem to be being mixed to two channels upon playback, which is not what I want to happen.


So I'm looking for guidance on how to structure the data.  Seems like the answer may be different based on what format of video file and/or player(s) are expected for use.


I imagine creating derivatives as we have with our video with 2-channel audio, similar to the commands below but perhaps with more explicit control over audio streams/channels.


ffmpeg -i input.mov -b:v 3000k -c:v mpeg4 -c:a libvo_aacenc output.mp4


ffmpeg -i input.mov -b:v 7000k -c:v prores -c:a libvo_aacenc output_7000k.mov


ffmpeg - i input.mov -b:v 7000k -c:v msmpeg4v2 -c:a mp3 output_7000k.avi


I'd appreciate any advice and/or links to reference material anyone chooses to send my way!  The answers may not be straightforward, so even questions to ask myself will be greatly appreciated.


Karl Fitzke