How do I enable the ac3 passthrough so that my external decoder indicates "Dolby Digital" sound and I get surround sound?
I have a
Creative Labs SB0400 Audigy2 Value card installed on a Fedora Core 4 machine and it shows up correctly using lspci as below
Code:
#/sbin/lspci | grep audio
02:00.0 Multimedia audio controller: Creative Labs SB0400 Audigy2 Value
My modprobe.conf uses the
emu101k driver as shown below
Code:
# ALSA portion
alias snd-card-0 snd-emu10k1
options snd-card-0 index=0
install snd-emu10k1 /sbin/modprobe --ignore-install snd-emu10k1 && /usr/sbin/alsactl restore >/dev/null 2>&1 || :
remove snd-emu10k1 { /usr/sbin/alsactl store >/dev/null 2>&1 || : ; }; /sbin/modprobe -r --ignore-remove snd-emu10k1
The audio devices for my sound card are shown below
Code:
# cat /proc/asound/devices | grep audio
19: [0- 3]: digital audio playback
18: [0- 2]: digital audio playback
26: [0- 2]: digital audio capture
25: [0- 1]: digital audio capture
16: [0- 0]: digital audio playback
24: [0- 0]: digital audio capture
The audio devices can also be displayed using aplay -l as below
Code:
# aplay -l | grep Audigy
card 0: Audigy2 [Audigy 2 Value [SB0400]], device 0: emu10k1 [ADC Capture/Standard PCM Playback]
card 0: Audigy2 [Audigy 2 Value [SB0400]], device 2: emu10k1 efx [Multichannel Capture/PT Playback]
card 0: Audigy2 [Audigy 2 Value [SB0400]], device 3: emu10k1 [Multichannel Playback]
What device should I use to play audio? And If I want to play AC3 using SPDIF (Coaxial) through an external Dolby Digital Decoder what device do I use?
Using device 0, I am able to play sounds using SPDIF.
Code:
$ aplay -D hw:0,0 /usr/share/sounds/KDE_Startup.wav
Playing WAVE '/usr/share/sounds/KDE_Startup.wav' : Signed 16 bit Little Endian, Rate 22050 Hz, Mono
None of the others devices work though with different errors
Code:
$ aplay -D hw:0,1 /usr/share/sounds/KDE_Startup.wav
aplay: main:542: audio open error: No such file or directory
$ aplay -D hw:0,2 /usr/share/sounds/KDE_Startup.wav
aplay: main:542: audio open error: No such device
$ aplay -D hw:0,3 /usr/share/sounds/KDE_Startup.wav
Playing WAVE '/usr/share/sounds/KDE_Startup.wav' : Signed 16 bit Little Endian, Rate 22050 Hz, Mono
aplay: set_params:889: Access type not available
If I use a DVD with AC3 sound with the following command it works well and I get two channel sound
Code:
$ mplayer -ao alsa:device=hw=0.0 dvd://1
Mplayer shows the following alsa output
Code:
alsa-init: 1 soundcard found, using: hw:0,0
alsa: 48000 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little Endian
AO: [alsa] 48000Hz 2ch s16le (2 bps)
If I then enable ac3 passthrough I get a clicking sound on my speakers when using the following command
Code:
$ mplayer -ao alsa:device=hw=0.0 -ac hwac3 dvd://1
The mplayer alsa output is
Code:
alsa-init: 1 soundcard found, using: hw:0,0
alsa: 48000 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little Endian
AO: [alsa] 48000Hz 2ch ac3 (1 bps)
If I use the "-ac hwac3" flag with other devices "hw=0.1 or hw=0.2 or hw=0.3" I do not get any sound.
How do I enable the ac3 passthrough so that my external decoder indicates "Dolby Digital" sound and I get surround sound?
