[FFmpeg-devel] Channel layouts for aac encoding/decoding and vorbis decoding

Jason Tackaberry tack
Mon Aug 10 15:53:58 CEST 2009


On Mon, 2009-08-10 at 14:24 +0200, Robert Swain wrote:
> Looking at Table 1.17 - Channel Configuration in 14496-3:
> center front speaker
[...]
> left, right front speakers
[...]
> center front speaker; left, right front speakers
[...]
> center front speaker; left, right center front speakers; rear surround
> speakers
[...]
> center front speaker; left, right front speakers; left surround, right
> surround rear speakers

FWIW, these seem to be the orders defined in aacenc.c:aac_chan_configs[]
as well.

So, I now understand that the input/output layouts _should_ be according
to the WAVEFORMATEXTENSIBLE order, but resolving these differences is
mainly a matter of time/motivation/etc.

In the interest of getting MPlayer in a functional state with respect to
channel layouts, I'm wondering how likely things are to change in the
next while.  If the current input/output layouts for vorbis and aac are
likely to remain unchanged in the medium term, it makes sense to adhere
to the current layouts.

Thanks,
Jason.




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