[FFmpeg-user] Strange mapping/tagging/stream correlation behavior

[Mike Scheutzow]

Christian wrote:
> Hi,
> 
> so here comes my second question about ffmpeg on this list!
> 
> The map options are not working as I would expect. Infact, i can't
> think of a reason why it's behaving this way.
> ...
> 
> [localhost:/Volumes/Various/Movies]% ffmpeg -i movie.mkv -i movie.mkv
> -c:v:0:0 copy -c:a:0:1 libfaac -c:a:1:1 ac3 -tag:0 avc1 -tag:1 mp4a
> -tag:2 ac-3 -map 0:0 -map 1:1 -map 0:1 movie.m4v

Your first problem is that the -c index value uses *output* stream 
numbers. And secondly, the command line documentation gives no 
indication that two numbers are permitted.

http://ffmpeg.org/ffmpeg.html#toc-Stream-specifiers-1

So basically, since your command line makes no sense, ffmpeg internally 
forced a stream order that would create a valid file.

The -map option uses *input* stream numbers, and must be specified in 
the order: map-for-out-stream-0, map-for-out-stream-1, etc.


Mike Scheutzow