[MPlayer-dev-eng] [PATCH] hwac3 support DTS WAV passthrough

[Compn]

On Sat, 17 Nov 2007 04:31:51 +0800, Ulion wrote:

>2007/11/13, Ulion <ulion2002 at gmail.com>:
>> Hello,
>>
>> Original hwac3 only support 48kHz sample rate to passthrough, and
>> only support 16bits BE DTS audio stream. Indeed that's only 1 of 4
>> DTS audio stream format, there also have 16bits LE, 14bits BE,
>> 14bits LE. Specially, normal DTS WAV is 44.1kHz 14bits LE DTS stream.
>> There's one way to passthrough DTS WAV is add '-ac +pcm' to force
>> mplayer treat it as raw pcm format, some receiver will detect the DTS
>> audio and play it well.
>> But some receivers does not support passthrough by this method, so I
>> try to find out a way to passthrough it just like normal DTS track in
>> movies. We need to modify ad_hwac3 to make it support more dts
>> format, but after did this, we still have problem to passthrough DTS
>> WAV, that's because the fsize of DTS WAV is 4096 if it's in 14bits
>> mode, and the sample number per channel (nblks*32) is 1024, then
>> 1024 * 2ch
>> * 2(16bits sample size) just equal the fsize 4096, that make us have
>> no space to add an IEC 61937 header for the passthrough.
>> But finally I found a way to resolve this problem -- convert the
>> stream from 14bits format to 16bits format, that will save spaces
>> then we can add the IEC header, after convert, the fsize changed to
>> 3584. Now we can passthrough DTS WAV by hwac3, tested on both Intel
>> and PPC. If you want some sample to test, goto these site:
>>
>> http://www.sr.se/multikanal/english/e_index.stm
>> http://www.kellyindustries.com/sounds.html
>>
>
>If no objects, I will commit this in a week.
>


why is the change in hwac3 and not hwdts ?
maybe i just dont understand the code...

-compn