[MPlayer-users] Problem with sound volume in mplayer + alsa usb-audio

[Vladimir Mosgalin]

Hi Piotr Krukowiecki!

 On 2007.10.28 at 22:21:59 +0100, Piotr Krukowiecki wrote next:

> hardware volume control is a bit inconvenient. Video playback halts for half

This shouldn't happen, maybe it's alsa problem.

> second, and I don't have precise control of laudness level. I can't make it 
> quiet enough. I've tried -volstep 1 too.. 
> Anything can be done, or should I just use softvol?

Well it's not like softvol is bad, or reduces quality. Keeping hardware
volume level at 0 dB, tweaking software volume level to keep
the volume level more or less constant and do the real volume tweaking
on your amp/speakers/headphones/etc is probably the nicest way overall.

> I'm using mplayer 1.0rc2 with alsa 1.0.15. My sound card is a built-in cm6501
> chipset handled by snd_usb_audio driver.

Sorry, I don't quite get this. You say that your card is built-in, but
uses usb audio driver?

Can you show
cat /proc/asound/cards
and
/sbin/lsmod |grep snd
results?

You sure you are not using any so-called "usb speakers" or "usb
headphones", which actually don't utilize your internal sound card?

> I can hear voices even if I set volume level to 0% in alsamixer, so maybe this 
> is alsa's fault.

Depends on what do you mean. When you use stereo output, tweaking Master
and/or PCM level in mixer should change volume and mute sound completely
when set to 0%. In some situations, tweaking PCM level won't change
volume, because it's about something else than hardware output plug
that you use (for example, card can have two analog outputs, line out
and amplified out, and PCM / PCM2 mixers that correspond to each of
them).

Also note that a lot of USB devices don't support mixer anyway. However,
if your volume level actually changes when you change mixer settings,
but you still hear sound at 0%, it means that something is wrong.

Also all of this doesn't apply to 5.1/6.1/7.1 multichannel playback, in
which case you can get some really strange results, like the mixer you
are used to not working at all or changing only a few channels, while
leaving the rest of them the same.

-- 

Vladimir