[FFmpeg-devel] [PATCH 4/4] lavd/oss: implement surround playback.

Nicolas George nicolas.george at normalesup.org
Sun Feb 3 23:18:57 CET 2013

Le quintidi 15 pluviôse, an CCXXI, Paul B Mahol a écrit :
> I see. +2 if this is documented so better solution, if ever is found,
> can be fixed.

I can add the following comment:

 * libswresample can do channels reordering, but does not currently offer
 * guarantees that the samples are handled as opaque binary data, which is
 * necessary to handle non-native binary representations supported by the
 * device.

> This should be fine without alsa in name of file that does reordering.
> (Isn't it generic after all ...)

I agree on the principle, but as far as I know, ALSA is actually the origin
of this particular channel order. The channel order is documented,
indirectly, in various places of ALSA's headers and source code.

As far as I remember, I was not able to find any relevant part in the
documentation for OSS. Testing the reordering code on hardware with surround
output and a native OSS implementation would be a good idea, if possible.

And, still as far as I can remember, the Intel HDA spec defines a few
registers to control the various channels, but does not set any standard
about the order of the channels.


  Nicolas George
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20130203/6e5e41f1/attachment.asc>

More information about the ffmpeg-devel mailing list