ALSA


Ok, i’ve bought a new soundcard. A Creative Audigy 1 ES with model number SB0160.

The main problem i’ve got with my sblive 5.1 was a non-working master-mixer (and pcm) over spdif. Thats not really a big fault, there are a so called “Wave” mixer control to lower pcm-spdif volume.
Now this works really fine, master control works as expected. But now i’ve got another small problem, ac3 passthru from mplayer and co. pauses pcm streams (enabled IEC958 Raw Transfer) but there is no AC3 incoming on my a/v-receiver.

My first approach was to start ld10k1 and initialize the dsp with a new program thru init_audigy  script. And afterwards i can play ac3 passthru fine and normal pcm streams works also, inclusive the needed mixer controls.

Now i’m almost happy with this card. I will report the ac3 passthru problem still to alsa-bugtracker to get ac3 passthru also without ld10k1 patched dsp programs.

And now the next suprise, on the fly AC3 encoding works also…this was really a suprise to me, cause i don’t have attributed the problem to the soundcard. But now mplayer and vlc plays fine all multichannel-non-ac3 streams with on the fly generated ac3.

For mplayer it’s needed to use -channels 6 and -af channels=6. This way mplayer use automaticly the surround51 alsa profile and we need only one section for our asoundrc. See last message for details.

i’ve tried to use the a52 on the fly ac3 encoder alsa plugin.

But currently i got only choppy or noisy output from mplayer (choppy) and vlc (noisy, a lot of crackles).

I’ve used the following .asoundrc :

pcm.ac3enc {

type a52
bitrate 448
channels 6

}

for mplayer (-ao alsa:device=ac3enc -channels 6)

and

pcm.!surround51 {

type a52
card 0
channels 6
bitrate 384

}

for vlc (no special setup, only load a 6 channel file, for example some apple.com/trailers).