[alsa-devel] ALSA processor usage is too high

Adam Rosenberg adam at alcorn.com
Fri Nov 5 15:12:16 CET 2010

I am trying to decode 8 MP3 files simultaneously.  Each file is 3
minutes 11 seconds long.  When I just decode the files and copy the
PCM data to memory it takes 2 minutes 36 seconds.  When I do the same
test after opening 8 ALSA PCM streams and while writing data to them
it takes 4 minutes 37 seconds.  This is much too slow for what should
be a simple copy operation.

I need to have 8 MP3 files decoding and playing on our custom board.
I have taken the driver as far as I can on my own.  I am seeking
expert help to get this working as soon as possible.  I am sorry if
this was not the appropriate place to post such a request.  Please
contact me directly if you are interested in working on this project.

The custom board is setup as follows:

Analog Devices BF537 processor running uClinux from
svn://blackfin.uclinux.org/uclinux-dist/trunk uclinux-dist
Using alsa-lib-1.0.23 from http://www.alsa-project.org
Two Cirrus Logic CS42448 CODECs connected to BF537 SPORT0 Primary and
Secondary data lines in Multichannel mode
CS42448 configured for TDM (32 bits per channel * 8 channels = 256
bits per frame)
ICS661 Audio Clock at (256*48000Hz) connected to BF537 SPORT0 and Both
CS42448 CODECs for bit clocking
You can find the driver here:

Thank you,

Adam Rosenberg
Software Engineer

Alcorn McBride Inc.
3300 South Hiawassee
Building 105
Orlando, FL 32835

(407) 296 - 5800 ext. 5490

More information about the Alsa-devel mailing list