[lug] ac3 on spdif (chaintech av-710)

[Ben]

And by a corollary to Murphy's Law, as soon as I posted my question, I
figured out the solution. I don't really understand it, but I tried yet
another asound.conf file I found on the web and this one works. If
anyone cares to know the trick, the file is attached.

Thanks, 

Ben




On Sat, 2006-10-28 at 15:41 -0600, Ben wrote:
> Anyone have experience getting ac3 pass-through to spdif working with
> alsa / mplayer? I just bought a chaintech av-710 (chipset envy24pt) and
> I've got alsa setup with it (ice1724 module). I can output to the spdif
> optical output and get pcm/stereo fine. But I cannot play a dvd with ac3
> pass-through (surround sound). When I run
> 
> mplayer -ao alsa:device=spdif -ac hwac3 -aid 128 dvd://1
> 
> I get 
> 
> ...
> hwac3: switched to AC3, 384000 bps, 48000 Hz
> AUDIO: 48000 Hz, 2 ch, ac3, 384.0 kbit/25.00% (ratio: 48000->192000)
> Selected audio codec: [hwac3] afm: hwac3 (AC3 through S/PDIF)
> 
> ...
> 
> alsa-init: using device spdif
> alsa-init: format ac3 are not supported by hardware, trying default
> alsa-init: unable to set format: Invalid argument
> Could not open/initialize audio device -> no sound.
> 
> 
> If I'm reading that right, mplayer see ac3 on the dvd fine, (and outputs
> to spdif) but alsa doesn't think my sound card to handle the ac3. How
> can I get alsa to access ac3 audio? Seems odd that I can get digital
> output, but only in stereo format. 
> 
> Also, "aplay -L" shows items for surround sound, which seems good. 
> 
> side 'cards.pcm.side'
> surround40 'cards.pcm.surround40'
> surround41 'cards.pcm.surround41'
> surround50 'cards.pcm.surround50'
> surround51 'cards.pcm.surround51'
> surround71 'cards.pcm.surround71'
> iec958 'cards.pcm.iec958'
> spdif 'cards.pcm.iec958'
> 
> 
> aplay -l:
> **** List of PLAYBACK Hardware Devices ****
> card 0: AV710 [Chaintech AV-710], device 0: ICE1724 [ICE1724]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> card 0: AV710 [Chaintech AV-710], device 1: IEC1724 IEC958 [IEC1724
> IEC958]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> 
> 
> Attached is my /etc/asound.conf file
> 
> Any ideas welcome.
> 
> Thanks,
> 
> Ben
> 
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pcm.envy_spdifdmix {
        type dmix
        ipc_key 1337
        slave {
                pcm "hw:0,1"
                format S32_LE
                rate 44100
        }
}

pcm.envy_spdif {
        type plug
        slave {
                pcm envy_spdifdmix
        }
}

pcm.!default {
        type plug
        slave {
                pcm envy_spdifdmix
        }
}

# For ogle
#
pcm.!spdif {
        type plug
        slave {
                pcm "hw:0,1"
                format S32_LE
        }
}

# For mplayer ao (mplayer -ac hwac3 -ao alsa1x:mplayer)
# For vlc, use mplayer as alsa device
#
pcm.!iec958 {
        type plug
        slave {
                pcm "hw:0,1"
                format S32_LE
        }
}

pcm.mplayer {
        type plug
        slave {
                pcm "hw:0,1"
                format S32_LE
        }
}