Amarok + PulseAudio: volume control changes global volume

Nikos Chantziaras realnc at
Tue Jul 6 14:36:06 BST 2010

On 07/06/2010 04:21 PM, Colin Guthrie wrote:
> 'Twas brillig, and Nikos Chantziaras at 06/07/10 13:36 did gyre and gimble:
>> On 07/06/2010 11:38 AM, Colin Guthrie wrote:
>>> [...]
>>> So what is this logic? Well, the general premise is that h/w volume
>>> control is favoured whenever possible.
>> Why?  As I mentioned in another post, lowering hardware volume results
>> in a reduction of bit-depth, and thus sound quality.  PA is free to mix
>> at a higher bit-depth than the hardware supports in order to avoid this,
>> but the hardware can't.
> PA mixes the prior to sending it to h/w so doing so before applying
> volume changes is clearly going to be better quality.
> Essentially the aim is to avoid touching the audio stream if at all
> possible and that's what this approach does. As mentioned earlier it's
> the same approach taken in the latest Windows incarnations too.

I suppose this is acceptable with cheap speaker systems.  But when I 
have a higher quality system with its own volume control, I'd like to 
have sound card hardware volume at 0db so my speakers can have the full 
signal instead of something that's being attenuated.

But anyway, that's probably just me.

>> I hope you'll be able to solve any remaining issues with it
>> (mplayer with PA is something I simply cannot live with.)
> I've used mplayer with PA for about two or three years. There have been
> a couple bugs along the way but none that are not solved AFAIK. Works
> great here.

The main problem for me (while using latest PA and latest mplayer from 
SVN) was that seeking in a video is slow and glitchy.  For example, 
pressing the "left" button to go 5 seconds forwards results in the 
video/audio getting out of sync and mplayer is then playing the video at 
double speed for a few seconds, followed by the video being played at 
half speed for another few seconds.  Without PA, seeking is instant with 
no lag and no video-audio sync and speed problems.

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