The Access Grid team at Argonne
National Laboratory develops and releases the AG2 toolkit
for RedHat 7.3 and Windows platforms. Installation kits of AG2 for other platforms are also now available.
The Slackware 9.x installation kit includes a version of AccessGrid-rat
which is able to utilize native ALSA
0.9 drivers. Unfortunately a bug in the intel8x0 driver (or perhaps
in the chip itself?) results in 99% cpu usage when using AccessGrid-rat
in the default L16-mono mode. A workaround is to run AccessGrid-rat in
stereo mode, rather than mono.
A small change to the AG2 AudioService, described below, ensures that
AccessGrid-rat starts up in stereo mode. This precludes the necessity to
change the mono/stereo mode by hand for each new instance of
AccessGrid-rat.
Method
Stop all AG2 tools.
Make a backup copy of the file
/etc/AccessGrid/services/AudioService.zip
In some other directory, unzip the audio service file:
unzip /etc/AccessGrid/services/AudioService.zip
which should extract the files AudioService.py and AudioService.svc
Now edit the AudioService.py file and locate the line which reads:
options.append( "L16-16K-Mono" )
This is at line number 56 in the AG2.1.2 version of the AG2 toolkit.
Change this line to:
options.append( "L16-16K-Stereo" )
Save the file and quit the editer.
Now create a new AudioService.zip file with the command:
zip -0 AudioService.zip AudioService.py
AudioService.svc
Replace the original AudioService.zip with this new version:
cp AudioService.zip
/etc/AccessGrid/services/AudioService.zip
Done.
The next time AccessGrid-rat is started from the AG2 VenueClient, it
will start up in stereo mode.
Credits
The change to rat which allows it to utilize the ALSA 0.9 driver was
devised by Steve Smith of Vislab at the School of IT, University of
Sydney. See his ALSA driver
for rat page for details.
