[FFmpeg-devel] PATCH: 5.1 AAC SMPTE channel order with libfaad

Vladimir Pantelic pan
Mon Apr 5 21:59:39 CEST 2010

Jean-Yves Avenard wrote:

> Another thing I've noticed not to work properly in ffmpeg's own AAC
> decoder is the downmix from 5.1 to stereo. Last I check, the center
> channel was missing, so typically, you loose most of the dialogues.

there is no downmix support in ffaac, you have to do that outside of
the decoder. atm only a few decoders like AC3 and DTS support it
internally. you will see that aac ignores requested_channels and
returns the full number of channels, so of course you miss the
center if you only use 2 channels...

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