[FFmpeg-devel] Handling dual language mono audio encoded as stereo

Anssi Hannula anssi.hannula
Sun Feb 14 18:32:08 CET 2010

Hi all!

Some nordic DVB channels encode e.g. four mono tracks with different languages 
into two stereo tracks (mpeg layer 2). The ISO639 language descriptor then has 
both language codes, separated by a null byte. This is probably a remnant from 
pre-DVB era, but we should somehow handle it nevertheless.

How should we handle this, what do you think?

Attached is a patch which simply sets language tag to e.g. "nor+fin" for dual-
language stereo tracks. Seems to show up correctly in ffplay (though of course 
there doesn't seem to be a way to choose a single channel from stereo track in 

Anssi Hannula
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