[mythtv] [mythtv-commits] mythtv commit: r24454 by jyavenard
Colin Guthrie
mythtv at colin.guthr.ie
Thu May 6 09:53:32 UTC 2010
'Twas brillig, and mythtv at cvs.mythtv.org at 06/05/10 09:44 did gyre and
gimble:
> An alternative is to unconditionally increase the buffer with"
> echo 512 > /proc/asound/card1/pcm7p/sub0/prealloc
Purely for reference, if a distro ships with PulseAudio, then they
generally include this following kernel patch:
http://svn.mandriva.com/cgi-bin/viewvc.cgi/packages/cooker/kernel/current/PATCHES/patches/sound-alsa-hda_intel-prealloc-4mb-dmabuffer.patch?view=markup
(same as:
http://cvs.fedoraproject.org/viewvc/rpms/kernel/devel/hda_intel-prealloc-4mb-dmabuffer.patch?view=markup)
I believe Ubuntu also does this but I don't follow their development too
closely.
This increases the DMA buffer to 4meg on HDA class hardware. This allows
for larger audio buffers which mean PulseAudio can get the 2s+ latency
that is desirable for playing audio/video on mobile devices to save power.
i.e. on my system:
[colin at jimmy boot]$ cat /proc/asound/card0/pcm0p/sub0/prealloc
4096
[colin at jimmy boot]$ cat /proc/asound/card0/pcm1p/sub0/prealloc
4096
--
Colin Guthrie
myth(at)colin.guthr.ie
http://colin.guthr.ie/
Day Job:
Tribalogic Limited [http://www.tribalogic.net/]
Open Source:
Mandriva Linux Contributor [http://www.mandriva.com/]
PulseAudio Hacker [http://www.pulseaudio.org/]
Trac Hacker [http://trac.edgewall.org/]
More information about the mythtv-dev
mailing list