Am Sonntag, 13. Mai 2012 schrieb Modestas Vainius: > Hello, > > On sekmadienis 13 Gegužė 2012 12:45:27 Martin Steigerwald wrote: > > So while I can perfectly understand the "apt-get purge pulseaudio" > > reflex and I did it myself quite some times, I know that Pulseaudio > > can mix together different audio sources. And it seems to do that at > > a higher quality than ALSA. > > And what about latency?
Hmmm, good one. Beware rant ahead: I do not seek around during audio playback a lot, so I don´t have much first hand experience. And then Amarok + Phonon is in between as well when I press play or seek. So its difficult to say what is causing which latencies. But I had quite some long lasting audio hichups on that machine, even up to about a minute (!) although rtkit was installed and promoted pulseaudio threads to real time priority. I was quite puzzled by this and already thought audio playback has completely stopped. But eventually it continued then. (Rarely Amarok just stopped playing for whatever reason.) That might be related to the aged BTRFS filesystems on the machine, that are quite slow at the moment. (So slow that a SSH login can take 15 seconds to the prompt - with I/O accesses happening. Not to speak of installing or removing packages via dpkg. I consider redoing the filesystems or trying to balance them - but then balancing the / filesystem on my T520 has lead to a serious performance loss that I reverted by redoing that filesystem from scratch. So maybe I will switch to Ext4 as well. Or replace the T23 by the T42 I have not in regular use right now.) But then, after removing Pulseaudio I rarely get hichups anymore - with the same BTRFS filesystems in use - and when so there are just a knack for a fraction of a second. Ideally I would get no hicchups at all and it once was so. (2.6.23 kernel here CFS was introduced, but then this has been XFS.). On the ThinkPad T520 I am writing this mail on I have no such issues, but it has way more processing power and dualcore with hyperthreading (Sandybridge i5) + Intel SSD 320 - high latencies on this machine would point to really inefficient software I think. Seeks during movie playing are fast in Kaffeine, which AFAIR still uses Xine directly, but with VLC when I press pause audio plays plays on for some seconds, and when I resume it takes some seconds till I hear audio again. (But then in Kaffeine DVD menus are somewhat broken at times, Kaffeine doesn´t react on mouse clicks on menu entries, while they work fine in VLC.) So no, I am not convinced regarding the overhead that Pulseaudio seemed to introduce. It does not seem to matter much on faster machines, but on lower end devices I have seen a big difference. I would like the mixing routines in ALSA be brought to a quality that Pulseaudio can provide and have all of this in kernel. For me Pulseaudio is quite controversial. The bugs, the audio hichups I did not have in that amount and length before, all not that convincing to me. But the sound output quality via USB sound card has been awesome. That said in the whole I think multimedia experience could be a lot better on Linux. You probably would understand what I mean when I show you Sam440ep 667 PowerPC embedded media playback performance and latency on AmigaOS 4.1 [1]. It had difficulty playing DVD decently, but on what it could play with DvPlayer, reaction to seeks has been instant. Maybe with MPlayer on Linux. But then thats the most uncomfortable player I have ever seen. I´d like: - good gui - DVD + DVD menus work nicely - instant seeks (low latency) - automatically moves to USB soundcard if available (Pulseaudio moves faster than Phonon alone I found, if configured properly. But sometimes it doesn´t recnognize the USB sound card correctly and sometimes I need to use pavucontrol to switch outputs although in Phonon settings the USB sound card is first) - easy to understand and configure I have the feeling that there are too many layers involved and thus to many ways to introduce bugs and too many combinations to test. [1] While its not completely fair, cause using Totem on Linux and MPlayer on AmigaOS 4.1 and Linux may not have accelerated video drivers for that machine, its still impressive: http://www.youtube.com/watch?v=0_1PjOEFPTk (sure AmigaOS 4.1 does less, has no memory protection and stuff like that, but still I do think Linux should be able to do better) -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To UNSUBSCRIBE, email to debian-kde-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/201205131420.13102.mar...@lichtvoll.de
