Linked by Thom Holwerda on Thu 7th Jul 2011 17:36 UTC, submitted by vivainio
Linux.FR has an interview with Lennart Poettering of PulseAudio and systemd fame (among others). Regarding PulseAudio: "I can understand why people were upset, but quite frankly we didn't really have another option than to push it into the distributions when we did. While PulseAudio certainly wasn't bug-free when the distributions picked it up the majority of issues were actually not in PulseAudio itself but simply in the audio drivers. PulseAudio's timer-based scheduling requires correct timing information supplied by the audio driver, and back then the drivers weren't really providing that. And that not because the drivers were really broken, but more because the hardware was, and the drivers just lacked the right set of work-arounds, quirks and fixes to compensate for it."
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RE[6]: Broken audio hardware
by Alfman on Fri 8th Jul 2011 05:11
in reply to "RE[5]: Broken audio hardware"
Member since:2011-01-28
_txf_,
Thank you for the link, definately informative. However it seems to contradict Lennart's recent statements in a few places. Particularly:
"We become much less dependant on what the sound hardware provides us with. We can configure wakeup times that are independant from the fragment settings that the hardware actually supports."
From your link, the main difference from traditional audio processing is that "pulse audio glitch-free" opts not to use sound card timers/IRQs and use system timers/IRQs instead to provide even lower latency than is available through the sound card. Pulse audio can therefor update the DMA buffer at any time without synching with the sound card timer.
This is great (no sarcasm), but I don't get why he claims a break in compatibility was necessary. What technical reason is there that pulse audio could not revert to sound card IRQs instead of breaking things? In the absolute worst case, this would have resulted in higher latency, which is at most a minor annoyance.
I'm not understanding the technical reason that pulse audio couldn't revert to using sound card IRQs as they were intended instead of breaking sound support all together? Can someone clear this up?
RE[7]: Broken audio hardware
by _txf_ on Fri 8th Jul 2011 09:25
in reply to "RE[6]: Broken audio hardware"
Member since:2008-03-17
From your link, the main difference from traditional audio processing is that "pulse audio glitch-free" opts not to use sound card timers/IRQs and use system timers/IRQs instead to provide even lower latency than is available through the sound card.
From my understanding the goal here is generally the opposite (to allow application that are not affected by latency to provide sound output at the highest latency possible yet have the flexibility for low latency).
I'm not understanding the technical reason that pulse audio couldn't revert to using sound card IRQs as they were intended instead of breaking sound support all together? Can someone clear this up?
The thing is that using the sound card irqs would result in generating an interrupt for every fragment of sound that is sent to the soundcard.
The fragment size is fixed by the soundcard and not the system, hence not dynamically reconfigurable. Also note that the soundcard has no information on the system and as such cannot make any judgements on the best solutions.
Features
Linked by Thom Holwerda on 06/13/13 14:35 UTC
The third and final WWDC product I want to talk about is - of course - OS X 10.9 Mavericks. While iOS 7 was clearly the focus of this year's WWDC, its venerable desktop counterpart certainly wasn't left behind. Apple announced OS X 10.9 Mavericks, the first OS X release not to carry the name of a big cat.
Linked by Thom Holwerda on 06/11/13 17:07 UTC
We already talked about iOS 7 yesterday (after a night of sleep, it's only looking worse and worse - look at this, for Fiona's sake!), so now it's time to talk about the downright stunning and belly flutters-inducing new Mac Pro. As former owner and huge, huge, huge fan of the PowerMac G4 Cube - I haven't been this excited about an Apple product since, well, I would say the iMac G4. This is the Apple I used to love.
Linked by Thom Holwerda on 06/10/13 23:13 UTC
Apple held its big keynote event thing at WWDC earlier this evening, but since I was away with friends I've had to read up on it later in the evening. The company announced iOS 7, OS X 10.9 Mavericks, and they gave a preview of the new Mac Pro. Especially the Mac Pro impressed me, and while iOS 7's new Holo/Metro-inspired theme looks messy and garish to me, I do commend Apple for finally breaking the mold. This news item will focus on iOS 7 - I'll dive into the Mac Pro and OS X 10.9 tomorrow (it's late here now).
Linked by Thom Holwerda on 06/08/13 14:57 UTC
And yes, the PRISM scandal is far, far from over. More and more information keeps leaking out, and the more gets out, the worse it gets. The companies involved have sent out official statements - often by mouth of their CEOs - and what's interesting is that not only are these official statements eerily similar to each other, using the same terms clearly designed by lawyers, they also directly contradict new reports from The New York Times. So, who is lying?
Linked by Thom Holwerda on 06/07/13 11:40 UTC
This story is getting bigger and bigger. Even though most Americans probably already knew, it is now official: the United States government, through its National Security Agency, is collecting the communications and data of all American citizens, and of non-Americans using American services, through a wide collaboration with the large companies in technology, like Apple, Google, Microsoft, Facebook, and so on. Interestingly enough, the NSA itself, as well as the US government, have repeatedly and firmly denied this massive spying on Americans and non-Americans took place at all.
Linked by Thom Holwerda on 06/04/13 12:45 UTC
Ah, patents - the never-ending scourge of the technology industry. Whether wielded by companies who don't actually make any products, or large corporations who abuse them because they can't compete in the market place or because they're simply jerks, they do the industry a huge disservice and are simply plain dangerous. According to The Wall Street Journal (circumvention link), president Obama is about to take several executive actions to address patent trolls - which may seem like a good idea, but I am very worried that all this will do is strengthen the positions of notorious patent system abusers such as Apple and Microsoft.
Linked by nfeske on 05/31/13 10:12 UTC
With version 13.05, the developers of the Genode OS Framework take measures to ensure that Genode continues to scale well with a growing number of users and the steadily broadening platform coverage. Further highlights are the improved SoC support for Exynos 5, OMAP4, Raspberry Pi, i.MX, and new components for realizing headless systems.
Linked by Thom Holwerda on 05/29/13 16:59 UTC
At the D11 conference, Apple CEO Tim Cook once again took the stage to be interviewed by Walt Mossberg and Kara Swisher. While most of the interview can be replicated by picking and reading 10 random Apple fanblog stories - there were still a number of very interesting things that warrant some closer scrutiny.
Linked by Thom Holwerda on 05/24/13 17:26 UTC
So, the Xbox One disaster continues. Microsoft's policy for dealing with the used games market has reportedly leaked - and it's a clear and direct attack to destroy the used games market. Prices for used games will be set at the retail value of a new game, and retailers have to hook into Microsoft's computer systems and comply with Microsoft's terms and conditions.
Linked by Thom Holwerda on 05/21/13 21:38 UTC
At an event earlier today, Microsoft unveiled the next Xbox - the third model, but confusingly named Xbox One. The big focus was TV, integrated Kinect, and all the other stuff we all expected to be forced down our throats. I think it took them 25 minutes to actually come to what should be the core of the story: gaming. Nothing groundbreaking in the gaming department, except for how Microsoft intends to handle the used games market and borrowing games from friends: pay up, buddy!More Features »
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2008-03-17
Ah, but is that because Pulse is so much better than everything else (OSSv3, OSSv4, FreeBSD OSS, OpenBSD sound, etc)? Or just because ALSA sucks so horribly?
The fact that projects use Pulse over raw ALSA just shows how bad raw ALSA is; it has no reflection whatsoever on any other audio stacks.
With the exception of Bluetooth audio, everything you can do with Pulse, I can do on FreeBSD using "that poor pathetic OSSv3", including all the different mixing of channels, redirecting of the network, multiple soundcards, multiple sources, etc.
Oss does not do high latency audio or timer based audio. So every sound is data transfer operation happens synchronously. So if you have a 10 min audio stream the bus stays active for the entire 10 minutes. With pulse it is upload chunk, then sleep some time then upload another etc...
see this, it explains it far better and more completely:
http://0pointer.de/blog/projects/pulse-glitch-free.html
Edited 2011-07-07 21:43 UTC