[Alsa-user] can't seem to get ac3 passthrough working with ymfpci

[Brian J. M. <br...@in...>]

I've been trying and trying and I just can't seem to get DD/DTS/AC3 to
work.  My receiver receives PCM just fine so at least I know the
physical bits are working.

I have tried both mplayer and ac3dec to drive the card into decoding AC3
but no luck.  I believe I have the mixer settings correct.  In fact I
think I have everything unmuted and at somewhere in the 2/3 volume
range.  I have IEC958 Loop disabled/muted and Direct Recording Source
set to IEC958.

When I use say mplayer to play a raw ac3 file (which it can downmix and
play analog through the liba52 codec) with:

# mplayer -v -ao alsa -afm hwac3 /video/Bjorn_Lynne-A-Lifetime-Of-Moments_\=
(5-1_surround\).ac3

mplayer tells me:

Trying to force audio codec driver family hwac3...
Opening audio decoder: [hwac3] AC3/DTS pass-through S/PDIF
dec_audio: Allocating 8192 bytes for input buffer.
dec_audio: Allocating 16384 + 65536 =3D 81920 bytes for output buffer.
No accelerated IMDCT transform found
hwac3: switched to AC3, 448000 bps, 48000 Hz
AUDIO: 48000 Hz, 2 ch, ac3, 448.0 kbit/29.17% (ratio: 56000->192000)
Selected audio codec: [hwac3] afm: hwac3 (AC3 through S/PDIF)
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Building audio filter chain for 48000Hz/2ch/ac3 -> 0Hz/0ch/??...
[libaf] Adding filter dummy=20
[dummy] Was reinitialized: 48000Hz/2ch/ac3
[dummy] Was reinitialized: 48000Hz/2ch/ac3
alsa-init: requested format: 48000 Hz, 2 channels, 100
alsa-init: using ALSA 1.0.11
alsa-spdif-init: playing AC3, 2 channels
alsa-init: using device iec958:{CARD 0 AES0 0x02 AES1 0x82 AES2 0x00 AES3 0=
x02}
alsa-init: pcm opend in blocking mode
alsa-init: chunksize set to 1024
alsa-init: fragcount=3D16
alsa-init: got buffersize=3D65536
alsa-init: got period size 1024
alsa: 48000 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little End=
ian
AO: [alsa] 48000Hz 2ch ac3 (1 bytes per sample)
AO: Description: ALSA-0.9.x-1.x audio output
AO: Author: Alex Beregszaszi, Zsolt Barat <jo...@st...>
AO: Comment: under developement
Building audio filter chain for 48000Hz/2ch/ac3 -> 48000Hz/2ch/ac3...
[dummy] Was reinitialized: 48000Hz/2ch/ac3
[dummy] Was reinitialized: 48000Hz/2ch/ac3
Video: no video
Freeing 0 unused video chunks.
Starting playback...

But still the receiver does not kick into DD to decode.

ac3dec shows/does:

# ac3dec -C /video/Bjorn_Lynne-A-Lifetime-Of-Moments_\(5-1_surround\).ac3=20
Using PCM device 'plug:iec958:{AES0 0x2 AES1 0x82 AES2 0x0 AES3 0x2}'
AC3 Stream 48.0 KHz 448 kbps

But again, no DD decoding.

Any ideas?

b.

--=20
My other computer is your Microsoft Windows server.

Brian J. Murrell