[MPlayer-users] ALSA (0.9.1) + mplayer (0.90rc4) + Audigy2 + channels & surround problem

Corey Hickey bugfood-ml at fatooh.org
Sat Mar 15 01:16:07 CET 2003


gabor wrote:
> i think you are correct :) my sblive does the same....
> 
> btw. if talking about alsa...
> 
> what volume controls do you use?
> i always tried to switch from oss to alsa,
> but i always failed to find the correct volume controls ( there are LOTS
> of them in alsamix ).
> 
> for example in oss it's simple:
> front-volume = VOL * PCM
> rear-volume  = OGAIN * PCM
> 
> so if i want to adjust the volume globally i use the PCM volume control,
> if separately i use VOL or OGAIN.
> 
> which volume controls do you use in alsa?
> 
> thanks,
> gabor
> 

Well, here's the way it seems to be. I'm using an sblive with alsa
0.90rc7.

-For the front, volume = Master * PCM * WAV

-In the case of mplayer audio.wav -ao alsa9,
	rear volume = "Surround Digital"

-In the case of mplayer audio51.wav -channels 4 -ao alsa9:surround40
	rear volume = "Wave Surround"

-I have an older sblive and can't test analog center or sub, but I
presume the "Center" and "LFE" controls do what they say they do.

-I don't have an amplifier to decode ac3 passthrough, so I don't know
what happens there.

Who knows why it ends up being so confusing... :)

Incidentally, I have a couple bugreports to write soon regarding alsa9
and 4 channels, but I want to upgrade to alsa 0.91 first. In short:

works: mplayer audio51.wav -ao alsa9:surround51 -channels 6
works: mplayer audio51.wav -ao alsa9:hw:1,0
fails: mplayer audio51.wav -ao alsa9:hw:1,0:surround51 -channels 6

Unless somebody spots an RTFM or known bug, I'll write up the full
report.



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