[FFmpeg-devel] [PATCH] aacdec: add support for dual mono in Japanese DTV

Akihiro TSUKADA atsukada at users.sourceforge.net
Wed Aug 22 03:57:03 CEST 2012

> so there is no way to distinguish dual mono from stereo and the user
> has to set this for each program she wants to watch manually ?

There is, at the level of MPEG TS system.
Each audio PES is tagged by PMT and
EIT describes the mapping from tag to encoding parameters
including channel configuration.
So those parameters are defined per program/show and
can change over time. (PMT is usually fixed and does not change).
TV receivers track EIT of the current station (TS, programID) and
output either channel (defaulting to the left) or
switch among them on user's request.

In addition, the Japanese DTV spec does not allow normal stereo audio
to have ADTS channel config field 0 or <SCE><SCE> config.

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