[FFmpeg-user] Enable all audio channels

Carl Eugen Hoyos cehoyos at ag.or.at
Sun Jun 23 20:02:07 CEST 2013

MI <mi.lists.ffmpeg <at> alma.ch> writes:

> If I understand correctly, there is no option to 
> enable (mark as "default") all audio tracks 
> simultaneously.

This is correct.
I suspect this is simple to implement for this 
special case, a very general solution is not 
trivial (but may have no use case).


> The frequent use case in professional 
> post-production for this is for delivering 
> Prores Quicktimes with all existing audio tracks.

Do I understand correctly that wherever you want 
to use these files, tracks that contain multi-channel 
audio are simply not accepted? Or is there another 
reason why you don't simply merge channels that 
belong to each other into one track?


> The common case I encounter is to have a single 
> language in the .mov, as 8 individual mono tracks 
> of the final audio mixes: Lt, Rt for stereo, and 
> L, R, C, Lfe, Ls, Rs for 5.1 (in that order).
> A related question would be how to label these 
> single mono tracks?

Just to avoid confusion:
For me, "order" and "label" are two completely 
different, partly orthogonal things.
Is it sufficient if 6 tracks (all being marked 
as "default") in the right order are in the mov 
file or is it necessary that all 6 tracks are 
"labeled" correctly?

Or in other words:
If you search for "first track enabled" in 
libavformat/movenc.c and change the "0x02" in 
that line to "0xf", does it work?

Carl Eugen

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