[MPlayer-dev-eng] [PATCH] real muting

Ivan Kalvachev ikalvachev at gmail.com
Wed Dec 21 19:24:45 CET 2005


2005/12/21, Diego Biurrun <diego at biurrun.de>:
> On Wed, Dec 21, 2005 at 03:48:58PM +0200, Ivan Kalvachev wrote:
> > 2005/12/16, The Wanderer <inverseparadox at comcast.net>:
> > >
> > > Any other opinions?
> >
> > I'm gonna kill the person who tries to commit this.
>
> You know, some arguments why the patch is bad or how it could be
> improved could do wonders here ;)

The drawback were already well discussed and I got the impression that
the patch is dropped without need to step in and flame.

But when I saw Wanderer mail I get scared that somebody could get the
crazy idea this is something that must be committed...

In short this patch cannot be improved because it is flowed by design.
Instead of using alsa mute it stops the playback.

The not so obvious side effects is that the volume stays at the same
level and for some  (old crappy) cards you could still hear the white
noise.

Other side effect is that the device could be used by another program
while muted and if you unmute it you are going to either quit mplayer
or loose ability to hear anything without mplayer restart.
This side effect is know as oss pause behaviour I had flamed before.
The big difference is that here we don't have pause but running
video...

I don't remember how it was solved, but this also mean that we must
change the time calculation at runtime, that would always be
hackish...

The mess with lost frames (a&v) and the big skip is clear and well
discussed. I personally am very pissed by such behaviour and it is the
main reason to prefer -ao alsa over -ao oss. (even despite the fact
that my donated sound card can play multiple streams).

The only benefit this driver have is that it stops the sound
processing. This probably saves us few DMA's but this could be hardly
give any benefit at video decoding speed. Is audio driver is smart
enough then probably it could do this internally.


Well... I don't want to go on with flames... I hope my answer is
technical enough to not be offensive.




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