[mythtv-commits] mythtv commit: r24454 by jyavenard

[mythtv at cvs.mythtv.org]

      Author: jyavenard
        Date: 2010-05-06 08:44:22 +0000 (Thu, 06 May 2010)
New Revision: 24454
   Changeset: http://svn.mythtv.org/trac/changeset/24454

Modified:

   branches/mythtv-hdaudio/mythtv/libs/libmyth/audiooutputalsa.cpp
   branches/mythtv-hdaudio/mythtv/libs/libmyth/audiooutputalsa.h

Log:

Add driver buffer resizing and modify requested buffer / fragment sizes in
aoalsa,
Refactor SetIECStatus to use new GetPCMInfo

ALSA default buffer size is 64kB. This turns out to be too short for some high-quality audio content.
We now increase the ALSA audio size if it turns out the current size isn't sufficient (like 192kHz, 24 bits audio).
You need write permissions on ALSA's device files for the driver buffer
resizing to work. For non-root users, a udev rule will likely be necessary.
Playback will continue if the buffer can't be resized when required but underruns are likely
to occur.
An alternative is to unconditionally increase the buffer with"
echo 512 > /proc/asound/card1/pcm7p/sub0/prealloc