[MPlayer-dev-eng] MPEG to S/PDIF passthrough

[Ulion]

2008/3/6, Ulion <ulion2002 at gmail.com>:
> 2008/3/5, Ilkka Karvinen <kartsan at gmail.com>:
>
> > There have been no comments on this patch. I'm wondering if there could be
>  >  people around here who have a home theater amplifier which supports MPEG
>  >  audio? It would be interesting to hear if this feature works with your
>  >  hardware. Especially if you are running mplayer on a bigendian machine
>  >  since I can't currently test this code on a such machine.
>  >
>  >  If your amplifier supports AC3/DTM decoding, its DSP may also support
>  >  MPEG audio. My old Harman Kardon amplifier uses Cirrus Logic's DSP
>  >  which supports it and that was my initial reason to start investigating
>  >  this stuff.
>  >
>  >  I send attached diff that Ulion made for me if you would like to give a try to
>  >  this feature. It adds new codec hwmp3 which redirects the MPEG frames to
>  >  hardware via S/PDIF.
>  >
>  >  I have tested it and it works with mp3 audio files and video files with
>  >  mp3 audio track. However, some mp3 files do not work and I don't know
>  >  why. My guess is that their frames are not recognised by my hardware.
>  >  There are no similarities with the failing samples. Another sample with
>  >  equal parameters (header bits are the same) may work flawlessly.
>
>
> found some problem about this patch:
>
>  in decode_audio():
>  +  uint16_t *buf16 = (uint16_t *)buf;
>
>  should this be put into the while loop and looks like this:
>
>  +  uint16_t *buf16 = (uint16_t *)(buf + toc);

I mean:
+  uint16_t *buf16 = (uint16_t *)(buf + tot);

and there's another type value for 'MPEG-2 with extension' it should
be 6 instead of 5.
there's also a type value for 'MPEG-2 layer-3 low sampling frequency'
referred by IEC 61937-4.
should these two type be handled in the code?

-- 
Ulion