[FFmpeg-cvslog] r20067 - in trunk/libavcodec: aac.c aacdectab.h

[Robert Swain]

2009/10/5 Andreas ?man <andreas at lonelycoder.com>:
> superdump wrote:

>> +static const int64_t aac_channel_layout[8] = {
>> + ? ?CH_LAYOUT_MONO,
>> + ? ?CH_LAYOUT_STEREO,
>> + ? ?CH_LAYOUT_SURROUND,
>> + ? ?CH_LAYOUT_4POINT0,
>> + ? ?CH_LAYOUT_5POINT0_BACK,
>> + ? ?CH_LAYOUT_5POINT1_BACK,
>
> I think you should remove out the _BACK postfix so it will be similar
> to how AC3 and DTS announce their channels.

The _BACK is needed to adhere to the specification in terms of the
channel positions. I offered this up for discussion in:

http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2009-August/074114.html

To quote myself:

5 channels
single_channel_element(), channel_pair_element(), channel_pair_element()
center front speaker; left, right front speakers; left surround, right
surround rear speakers

CH_LAYOUT_5POINT0_BACK ==
CH_FRONT_CENTER|CH_FRONT_LEFT|CH_FRONT_RIGHT|CH_BACK_LEFT|CH_BACK_RIGHT


6 channels (5.1)
single_channel_element(), channel_pair_element(),
channel_pair_element(), lfe _element()
center front speaker; left, right front speakers; left surround, right
surround rear speakers; front low frequency effects speaker

CH_LAYOUT_5POINT1_BACK ==
CH_FRONT_CENTER|CH_FRONT_LEFT|CH_FRONT_RIGHT|CH_BACK_LEFT|CH_BACK_RIGHT|CH_LOW_FREQUENCY



"surround rear" implies "back" to me.

If you have a good reason to change it though, I'll be fine with it.

Regards,
Rob