[ANNOUNCE] New Mixer Handling in PA 0.9.16/F12

Lennart Poettering mzerqung at 0pointer.de
Wed Jul 29 13:13:37 UTC 2009


On Wed, 29.07.09 09:46, Karel Zak (kzak at redhat.com) wrote:

> 
> On Tue, Jul 28, 2009 at 10:07:32PM +0200, Lennart Poettering wrote:
> > On Tue, 28.07.09 15:48, Bill Nottingham (notting at redhat.com) wrote:
> > 
> > > 
> > > Lennart Poettering (mzerqung at 0pointer.de) said: 
> > > > Please note that it is our intention not to wrap obsolete mixer
> > > > controls such as "CD", "PC Speaker", "MIDI" and so on. If you file a
> > > > bug asking for those to be wrapped we will disappoint you and
> > > > close the bug WONTFIX.
> > > 
> > > When you mean 'not wrap them', do you mean they're no longer
> > > selectable as a record source, if the hardware exports them?
> > 
> > Yes. You cannot select them as record source, you cannot mute or
> > unmute them, you cannot change their volume. "CD", "PC Speaker",
> > "MIDI" and so on are just obsolete. 
> 
> This reminds me your note:
> 
>     https://tango.0pointer.de/pipermail/pulseaudio-discuss/2009-July/004519.html
> 
>     PA does not make use of hardware mixing. And I don't plan to change
>     that. It's obsolete technology. CPUs these days come with extensions
>     such as MMX or SSE precisely for speeding up DSP tasks such as PCM
>     mixing. This is way more flexible that hw mixing, and definitely the
>     way to the future, both on the desktop and on embedded envs as well.
> 
> 
> The "obsolete technology" -- who made this decision? Is it your private
> opinion or any suggestion from sound card manufacturers?

It's my opinion. Which is based on not being blind to what's happening
around me.

> It seems that HW companies still produce the "obsolete technology".

Modern sound card designs don't do hw mixing anymore, it's like
fm synthesis or wavetable audio. It's simply not done in hw
anymore. The only exceptions are cards for gamers, i.e. Creative
cards. And uh, quite frankly those cards probably only have it because
they need at least something that distuingishes them from normal HDA
cards.

In my little array of sound cards I have here not a single one still
does hw mixing. So even if I wanted to add hw mixing support to PA I
couldn't because I have nothing to test with. Also given that these
days you find that feature only in Creative cards and Creative is
mostly anti-Free-Software I really see no point in spending a minute
on adding support for this to PA even if it would make technical
sense, which it doesn't.

Also, let's not forget smething: DirectSound in Vista does not support
hw acceleration for audio at all anymore:

http://connect.creativelabs.com/openal/OpenAL%20Wiki/OpenAL%C2%AE%20and%20Windows%20Vista%E2%84%A2.aspx

And CoreAudio never did either.

Creative is now pushing OpenAL since they apparently believe that hw
mixing just for hw mixing's sake is something that makes sense to
gamers -- even though it makes no sense at all to me.

But than again, if hw mixing is that important to you, I am happy to
merge patches if they are clean.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4




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