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

[Ulion]

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

-- 
Ulion
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