The Polypaudio sound server

Mike Hearn m.hearn at
Thu Sep 9 16:26:28 EEST 2004

> ALSA is limited to Linux, it is everything else than portable. ALSA is
> not network transparent. ALSA ist not esound compatible. ALSA is a
> driver API, not a sound server API.

Well, what I'm saying is that maybe this problem sits at a layer below 
the desktop. Sure ALSA is Linux specific but both Windows and MacOS can 
*also* do their own software mixing and resampling without apps having 
to use 3rd party sound servers.

I think FreeBSD has some kind of kernel mixer for OSS, or did at one 
point. Not sure if that's accurate, but I remember encountering it ...

As to compatibility etc, esound itself can have an ALSA backend. Network 
transparency - right, it's not. It *could* be with an additional plugin 
I think but such a plugin does not yet exist.

> And JACK isn't a sound server, its an audio connection kit.

Hmm, what's the difference? :)

> See above.

Well, no. You said that JACK isn't a sound server and that ALSA is Linux 
specific. But we already have, at minimum:

- esound
- aRts (ok so these two are pretty old)
- JACK (it can mix sound, right?)
- probably some others I've forgotten

Really the only one that caught on to any serious degree was esound. So 
I'm wondering if the sound server architecture is the right one at all.

Don't get me wrong. I'm not criticising Polypaudio, I've not used it but 
judging from the webpage it looks like a nice piece of work.

> Polypaudio is intended for replacing esound/arts, not OSS or ALSA. So
> I see no need in adding a compatibility layer for OSS/ALSA superseding
> esddsp.

I don't see how it solves the problem of apps randomly blocking or 
failing on busy DSP devices then. That is the problem you're trying to 
solve, right? (along with network transparency etc ..)

Unless *everything* goes via Polypaudio it'll have the same problem that 
esd, arts, and the rest already do. Arbitrary and random applications 
won't play audio because the device is already in use by the sound 
server, and we haven't really moved forward.

> Polypaudio is not for professional audio, polypaudio should be a sound
> server for desktop environments. Professional audio people will always
> want to access hardware at the lowest level possible. Every software
> layer will only increase latency. 

Last time this issue came up here (and it does, regularly), I think the 
Linux pro audio guys said that desktop environments could definitely use 
JACK but the pro audio world could not use anything else. Or words to 
that effect. Does it make sense to duplicate this component?

> It mixes "everything" together. Everything that connects to the sound
> server through its native protocol or the esound procotol (or few more
> other protocols)

Well if you define everything as "software that has plugins for it" then 
yes, it does. If you define everything as "all my software, including 
old games, random [proprietary] apps like RealPlayer/VMware/TuxRacer 
etc" then it doesn't and cannot do so without backwards compatibility code.

thanks -mike

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