[pulseaudio-discuss] Accessing audio as root

Colin Guthrie gmane at colin.guthr.ie
Fri Nov 27 02:37:03 PST 2009

'Twas brillig, and Markus Rechberger at 27/11/09 09:43 did gyre and gimble:
> The first behaviour this morning was that mplayer muted after 2-10
> seconds this morning
> The second behaviour after rebooting the PC was that audio didn't work
> because the alsa
> device was muted. I do not know if the first one is also somewhat
> related to the second behaviour
> and pavucontrol might have unmuted it this morning (after closing
> pavucontrol sound muted again -
> without changing anything in pavucontrol itself).

This is what is confusing me, pavucontrol wont unmute things by itself. 
It may however trigger behaviour that may sound like mute/unmute.

To explain, the glitch free system, by default, sets a fairly high 
latency (this is for power saving purposes). pulse clients can control 
this, but alsa clients via the plugin cannot.

When pavucontrol starts the latency is reduced so that vumeters in 
pavucontrol can give somewhat accurate results. It is this process that 
I think is triggering what you describe as mute/unmute, but what I think 
is probably more accurately represented as cork/uncork... i.e. mute 
implies that audio is sent ot the bit bucket, cork implies basically 
freezing audio consumption until it's ready.

e.g. if you run an audio track that is a recoding of someone slowly 
counting from 1 to 100, does your mute actually skip any numbers or does 
it just wait and then carry on where it left off as you close and open 

If so then I can see this being a problem with some apps, but for me at 
least mplayer is working fine with -ao pulse and -ao alsa, so this is a 
bit confusing that you are seeing this (if this was a fundamental 
problem with they way mplayer handled the timing, it would show up for 
both of us I'd have thought). Hence why this is a little odd.



Colin Guthrie

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