If a DVD is in the drive wmrack looks at for audio cds and
wmrack is running, I get about 24 times per second an error in
/var/log/messages, which puts a stress on the system.
Here is the message:
Sep 11 12:55:58 bonniot kernel: hdd: packet command error: status=0x51{
DriveReady SeekComplete Error }
Sep 11 12:55:58 bonniot kernel: hdd: packet command error: error=0x54
Sep 11 12:55:58 bonniot kernel: ATAPI device hdd:
Sep 11 12:55:58 bonniot kernel:   Error: Illegal request -- (Sense
key=0x05)
Sep 11 12:55:58 bonniot kernel:   Cannot read medium - incompatible
format -- (asc=0x30, ascq=0x02)
Sep 11 12:55:58 bonniot kernel:   The failed "Read Subchannel" packet
command was:
Sep 11 12:55:58 bonniot kernel:   "42 02 40 01 00 00 00 00 10 00 00 00 "

If I kill wmrack the messages cease to appear.

Ouch, that's no good!  I don't have a DVD player, but I'll look at
code and see if I can find anything obvious.

Thanks for the report.

I'm still not completely sure what the exact problem is.  And I still
don't have a DVD drive to test with.  Could I get you to try some
other (preferably small) cd players, and let me know of one (or more)
that don't have this problem?  Then I can compare the code.

thanks