Hi,
I'm trying to get Dolby AC3 SPDIF passthrough playback
over the TOSLINK optical output on a Yamaha YMF-744 based
card (Hoontech Digital XG).
I'm running Linux 2.4.19 on an x86-based PC with Alsa 0.9 rc7.
I also tried the Alsa version from CVS on 2003-02-01, but this made no
difference compared to rc7.
Digital output is activated for playback in /etc/asound.state
and all active controls in the mixer have been raised to an adequate level.
Normal 2-ch playback works fine on all three output ports
(analog out, coax digital out, optical digital out).
When I activate AC3 passthrough, my Dolby Digital decoder is unable
to find a valid signal. Playback has been tested with mplayer and
ac3dec.
Mplayer 0.90rc3 crashes, when activating the hwac3 filter.
####################################################################################
Output from mplayer:
mplayer -ao alsa9:hw:0,2 -ac hwac3 AC3test.avi
Playing AC3test.avi
AVI file format detected.
VIDEO: [DIV3] 576x432 24bpp 23.98 fps 1882.5 kbps (229.8 kbyte/s)
Clip info:
Software: Nandub v1.0rc2
==========================================================================
Forced audio codec: hwac3
Opening audio decoder: [hwac3] AC3 pass-through SP/DIF
No accelerated IMDCT transform found
AUDIO: 48000 Hz, 2 ch, 16 bit (0x400), ratio: 48000->192000 (384.0 kbit)
Selected audio codec: [hwac3] afm:hwac3 (AC3 through SPDIF)
==========================================================================
vo: X11 running at 1280x1024 with depth 24 and 32 bpp (":0" => local
display)
[x11] Detected wm is of class NetWM.
[x11] Detected wm supports STAYS_ON_TOP state.
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffdivx] vfm:ffmpeg (FFmpeg DivX ;-) (MS MPEG-4 v3))
==========================================================================
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: testing and bugreports are welcome.
alsa-init: requested format: 48000 Hz, 2 channels, AC3
alsa-init: soundcard set to iec958:AES0=0x2,AES1=0x82,AES2=0x0,AES3=0x2
alsa9: 48000 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little
Endian
AO: [alsa9] 48000Hz 2ch AC3 (1 bps)
Building audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/8bit...
[format] Sample format big endian AC3 not yet supported
Couldn't find matching filter / ao format! -> NOSOUND
MPlayer interrupted by signal 11 in module: uninit_acodec
- MPlayer crashed by bad usage of CPU/FPU/RAM.
Recompile MPlayer with --enable-debug and make a 'gdb' backtrace and
disassembly. For details, see DOCS/bugreports.html#crash.b.
- MPlayer crashed. This shouldn't happen.
It can be a bug in the MPlayer code _or_ in your drivers _or_ in your gcc
version. If you think it's MPlayer's fault, please read
DOCS/bugreports.html
and follow the instructions there. We can't and won't help unless you
provide
this information when reporting a possible bug.
alsa-uninit: pcm closed
#################################################################################################
I've also tested ac3dec, which doesn't crash but only delivers 2ch output.
I called ac3dec with all 3 options for IEC958 output which gave me different
results.
./ac3dec -P test.ac3
Using PCM device 'iec958:AES0=0x87,AES1=0x0,AES2=0x0,AES3=0x0'
AC3 Stream 48.0 KHz 448 kbps
(No sound is heard. Decoder indicates that there is no signal)
#############
./ac3dec -C test.ac3
Using PCM device 'iec958:AES0=0x2,AES1=0x82,AES2=0x0,AES3=0x2'
AC3 Stream 48.0 KHz 448 kbps
(No sound is heard. Decoder indicates that there is no signal)
#############
./ac3dec -R test.ac3
5.1 Mode 48.0 KHz 448 kbps Complete Main Audio Service
Using PCM device 'iec958:AES0=0x0,AES1=0x82,AES2=0x0,AES3=0x2'
(Sound is heard. Decoder indicates PCM 2-channel mode)
I'm not quite sure, whether this is a configuration problem or a
driver issue. Is it to possible to use SPDIF passthrough with
this card?
Thanks in advance,
Marcus
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