[alsa-devel] PS3 - Surround sound on SPDIF set-up

[Takashi Iwai]

At Tue, 03 Jul 2007 11:50:34 -0700,
GT Bradley wrote:
> 
> yes,
>   I am aware that AC3 is required,  I'm trying to get the AC3 
> pass-through configured. From your response, I understand now that 
> speaker-test is performing as expected, however I have tired other 
> things also:
>  I have some AC3 encoded test files,  and I have also tried installing 
> ffmpeg, and liba52.  and the ac3dec utility which I understand should 
> pass through the AC3/DTS encoded files, but I recieve:
> 
> [root at ps3 Surround-SDL-testfiles]# ac3dec -C dolby-canyon.ogg
> Using PCM device 'plug:iec958:{AES0 0x2 AES1 0x82 AES2 0x0 AES3 0x2}'
> ALSA lib conf.c:3939:(snd_config_expand) Unknown parameters {AES0 0x2 
> AES1 0x82 AES2 0x0 AES3 0x2}
> ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM iec958:{AES0 0x2 
> AES1 0x82 AES2 0x0 AES3 0x2}
> snd_pcm_open: Invalid argument
> Output open failed
> 
> However if I am planning to write ac3 to the linux driver, are you 
> saying that I would be better to write directly to the driver rather 
> than through the ALSA layer?

You need set up the configuration for alsa-lib.
Otherwise the iec958 PCM isn't defined.
Usually the card-specific configuration is stored in
/usr/share/alsa/cards/*.conf.


Takashi