[MPlayer-users] -ao alsa1x -ac hwac3,

[Tim Dodge]

Hi,

I'm trying to get hwac3 passthrough working on my xbox.

I'm running mplayer-1.0_pre4 using the alsa 1.0.4 intel8x0 drivers on a 
2.4.25 kernel in gentoo. My .asoundrc defines an input named digital 
that converts the rate to 48000Hz and outputs through the spdif hardware 
(hw:0,2).

If I play a file with an ac3 soundtrack using "-ao alsa1x:digital -ac 
a52," everything is fine; the soundtrack is converted to stereo PCM via 
the spdif, which my AV amp is happy to decode:

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: requested format: 48000 Hz, 2 channels, Signed 16-bit 
(Little-Endian)
alsa-init: soundcard set to digital
alsa1x: 48000 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit 
Little Endian
AO: [alsa1x] 48000Hz 2ch Signed 16-bit (Little-Endian) (2 bps)
Building audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/16bit...
Starting playback...

If I try "-ao alsa1x:digital -ac hwac3," I get:

Checking audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/8bit...
AF_pre: af format: 2 bps, 2 ch, 48000 hz, big endian AC3
AF_pre: 48000Hz 2ch AC3
alsa-init: requested format: 48000 Hz, 2 channels, AC3
alsa-init: soundcard set to iec958:AES0=0x2,AES1=0x82,AES2=0x0,AES3=0x2
ALSA lib setup.c:548:(add_elem) Cannot obtain info for CTL elem 
(MIXER,'IEC958 Playback AC97-SPSA',0,0,0): No such file or directory
alsa-init: playback open error: No such file or directory
Could not open/initialize audio device -> no sound.
Audio: no sound
Starting playback...

Which is suspiciously similar to what I get if I try "-ao alsa1x:spdif 
-ac a52,":

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: requested format: 48000 Hz, 2 channels, Signed 16-bit 
(Little-Endian)
alsa-init: soundcard set to spdif
ALSA lib setup.c:548:(add_elem) Cannot obtain info for CTL elem 
(MIXER,'IEC958 Playback AC97-SPSA',0,0,0): No such file or directory
alsa-init: playback open error: No such file or directory
Could not open/initialize audio device -> no sound.
Audio: no sound
Starting playback...

I'm wondering if this problem is similar to the one reported by Adar 
Dembo on 3rd May, here:

http://news.gmane.org/find-root.php?message_id=%3c1083631374.845.116.camel%40adard.stanford.edu%3e

Any advice would be very welcome!

Regards,
Tim Dodge