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

[Ulion]

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.

-- 
Ulion