[MPlayer-users] Identifying Surround Sound with MPlayer

[Reimar Döffinger]

Hello,
On Sat, Feb 09, 2008 at 09:45:54PM -0800, Corey Hickey wrote:
> That should suffice for details about AC3 and DTS; for the more general
> case, try looking at ID_AUDIO_NCH (which seems to be printed twice, so
> use the last one). That refers to the number of output channels, though,
> so you should probably add '-channels 6' to your command line;
> otherwise, some decoders (such as liba52) may automatically downmix and
> you'll see ID_AUDIO_NCH=2 for a 6-channel track.

Also, some code codecs like AAC always upmix to stereo since AFAICT it
is possible to have stereo information only in some frames.