Re: SPDIF and cs46xx ?

[Takashi Iwai <tiwai@suse.de>]

At Mon, 10 Mar 2003 22:15:40 +0100,
Gregoire Favre wrote:
> 
> On Mon, Mar 10, 2003 at 03:52:32PM +0100, Takashi Iwai wrote:
> 
> > ah, now got the point.
> > 
> > surround51 pcm is for ANALOG 5.1 output.  and it's NOT supported on
> > cs46xx yet.
> > 
> > the easiest way to check is to use ac3dec in alsa-utils.
> > run with -C option for AC3-passthru mode.
> 
> ;-)
> With -C I don't hear anything with my file, so with -P, but with -R I
> can hear the sound, but my receiver only tell me about stereo, no 5.1.
> 
> Something I really don't understand:
> 
> ./ac3dec -C /data/linux/dvb/from_beyond_the_edge_44k_256kbps.ac3
> Using PCM device 'iec958:AES0=0x2,AES1=0x82,AES2=0x0,AES3=0x2'
> AC3 Stream 44.1 KHz 256 kbps
> 
> Don't gives me any sound,

44.1kHz ac3 ?  then it likely doesn't work because ac3dec assumes
48k only.

> but
> ./ac3dec -D iec958:AES0=0x2,AES1=0x82,AES2=0x0,AES3=0x2 /data/linux/dvb/from_beyond_the_edge_44k_256kbps.ac3
> 5.1 Mode 44.1 KHz 256 kbps Complete Main Audio Service
> Using PCM device 'iec958:AES0=0x2,AES1=0x82,AES2=0x0,AES3=0x2'
> does (stereo only).

without -C option, it's not sent as a raw data.


> Where could I find info about those?
> 
> Oh, just for the info, for playing with mplayer, the abs option is
> really cool:
> 
> mplayer -dvd 1 -ao alsa9 -channels 2 -abs 3
> allow me to hear stereo sound with alsa:
> Checking audio filter chain for 48000Hz/2ch/16bit ->
> 48000Hz/2ch/16bit...
> AF_pre: af format: 2 bps, 2 ch, 48000 hz, little endian signed int 
> AF_pre: 48000Hz 2ch Signed 16-bit (Little-Endian)
> alsa-init: testing and bugreports are welcome.
> alsa-init: requested format: 48000 Hz, 2 channels, Signed 16-bit
> (Little-Endian)
> alsa-init: 1 soundcard found, using: hw:0,0
                                       ^^^^^^
the spdif device is hw:0,2.
i guess ther is an option in mplayer to specify the pcm name for
ALSA.  use "spdif" there instead of "hw:0,2".


ciao,

Takashi


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