On 07/10/2025 21.24, Ulf Zibis via ffmpeg-user wrote: > Hi, > > yes, i can simply transcode such files to MP3 with FFMPEG, but my question > is, how this is done in deep. > > Does FFMPEG simply extract the left and right front channels or is there some > calculation made from all 6 channels?
Use one of the following filter-complexes, Ulf: For 5.1(side), pan=stereo|FL<FL+FC+SL+LFE|FR<FR+FC+SR+LFE For 5.1(back), pan=stereo|FL<FL+FC+BL+LFE|FR<FR+FC+BR+LFE I have two observations: 1, There's no need to separately scale any of the channels because the 'less-than' sign (<) does that automatically, and 2, Don't try to use some sort of generalized equation like pan=stereo|FL<FL+FC+SL+BL+LFE|FR<FR+FC+SR+BR+LFE (unless the input really is 7.1 of course) because the extra, non-existing channels are apparently counted in even though they don't exist. Including non-existing channels will reduce the volume of the stereo that's produced. --Mark. _______________________________________________ ffmpeg-user mailing list -- [email protected] To unsubscribe send an email to [email protected]
