[LAD] [ANNOUNCE] Safe real-time on the desktop by default; Desktop/audio RT developers, read this!

Dave Phillips dlphillips at woh.rr.com
Tue Jun 23 12:46:07 UTC 2009

Patrick Shirkey wrote:
> I wouldn't go that far. Lennart has proven to be open to our 
> suggestions in the past and is prepared to work with everyone round 
> here on the matter of desktop integration and to a degree system design.

I hope so. As I read this thread I'm further convinced that the 
requirements for normal desktop audio and pro-audio are dissimilar 
enough to demand very close inspection of any system sound component 
added to a distribution or even to the kernel itself, especially any 
component with the capability of wrecking the low-latency soft realtime 
performance we've become accustomed to for serious recording on Linux. I 
do not say that PulseAudio is a culprit here, I'm only emphasizing the 
need for healthy vigilance regarding additions that have implication for 
the existing  working systems for serious recordists (i.e. JACK and ALSA).

> IMO what is missing at the moment is a unified plan from the LAD 
> community for desktop integration that is compatible with the unified 
> plan from the freedesktop community et al.

Ah, cat-herding. I agree with you, Patrick, I'm just not sure how easily 
it'll get done, if at all.

> What I see is that Lennart and the others who have worked on 
> pulseaudio have done such a good job at making the platform accessible 
> to the desktop community that it has now become the defacto standard 
> for Linux Audio.
> This was certainly helped by the insistence (for good reasons) that 
> JACK is not designed for normal users or non realtime desktop apps and 
> the lack of effort contributed to tackling the inherent issues.
> However we do have a problem now that needs to be sorted with 
> integrating pa and jack in a way that is easy for everyone to work with.

Do they need integrated at all ?

I'm currently writing an article that asks that question (among others 
re: the default Linux sound server). Frankly, I stand on the side of 
those users who want *nothing* between JACK and ALSA, so whatever 
solution finally presents itself, for me it must include the provision 
for completely eliminating it, with no ill effects upon the rest of the 
non-audio parts of the system. However, I also recognize the need for a 
solution a la PulseAudio for the normal user.

I'm becoming further convinced that serious Linux audio production is 
simply not going to be an out-of-the-box experience for users, that it 
will always require intervention on the user's part, and that that 
intervention will discourage some (many?) users from trying a Linux 
system for creative audio work. We represent a very thin slice of the 
Linux user pie, and our concerns don't appear to be priority concerns 
for mainstream distro maintainers. And maybe that's not a bad thing.

> Clearly Lennart has found that PA needs to be able to handle realtime 
> usage cases and is attempting in his best way to deal with those 
> problems. However there is soooo much cross over here that it is 
> becoming a dictatorial situation for those of us who are not 
> intrinsically tied too the pulse audio system.
> Hence it is in everyones best interests to make sure this issue is 
> resolved or else we will have another alsa vs oss situation on our 
> hands for the foreseeable future.

Ah, but what does PulseAudio have to contend with ? Where is its 
opposition ? Is there any other serious contender for the crown of the 
default Linux sound server ? Lennart seems happiest about PulseAudio's 
wide acceptance, which is fine, and I am glad to see him here trying to 
make the system work to everyone's satisfaction. It remains to see 
whether that's possible, but as long as PulseAudio can be easily and 
fully removed, uninstalled, or toggled off, without damage or hindrance 
to the rest of the system then I'm not sure if a real problem exists. 
*How* PulseAudio can be removed etc is perhaps a problem best resolved 
by the distro maintainers.

> By itself that is not a problem as that is the beauty of open source, 
> but for the average user it is a real headache.

Perhaps we should require that the kernel developers and mainstream 
distribution maintainers all run Ardour for three weeks and attempt at 
least two multitrack/multichannel recordings. At least by then they'd 
maybe have a better notion of what defines a system for serious 
recording. ;)

For my purposes the entire discussion boils down to this: Will 
PulseAudio negatively impact the excellent performance offered by 64 
Studio, Planet CCRMA, JAD, or any other audio-optimized distribution ? 
It appears that Lennart wants to make PulseAudio as transparent as 
possible to the end user, but when I need to see it, I want to see it 
all and I want to be able to control it completely, right down to 
eliminating any trace of it, if that's what I desire. Again I say, I 
have nothing against PulseAudio. I simply want a guarantee that its 
existence does not threaten the continued excellent performance I've 
come to expect from the kernels prepared for the audio-optimized 
distributions. If that scenario can be warrantied then I'm a happy camper.

Okay, I've rambled enough. Better minds are making better points, but I 
wanted to add my POV. Btw, I won't pretend to have followed this 
discussion in all its technicalities, but as a user the topic is a 
priority interest.



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