[mythtv-users] CX88 "Blackbird" audio razziness
mythtv at rodsbooks.com
Thu Mar 1 15:58:25 UTC 2007
A while ago I picked up a cheap used AVerMedia AVerTV M150-D card to use as a
backup tuner. This card is based on the Conexant 2388x chip and the 23416
MPEG-2 encoder chip using the "Blackbird" reference design. It uses the Linux
cx88, cx88-blackbird, and related drivers (it's reported to NOT work with the
ivtv drivers, so I've not tried them). After struggling for some time, I
finally got the card working in Linux and MythTV, but not completely. The
main issue is an audio "razziness" problem that crops up occasionally. When
this problem surfaces, it sounds as if people are speaking with kazoos in
their throats, making a recording pretty much useless. The problem is, as far
as I can tell, 100% certain to occur after changing channels in the live TV
viewer, but is much less likely to occur when doing a scheduled recording or
when entering live TV after the tuner has had a few minutes to "rest." I'm
using a 64-bit 22.214.171.124 kernel on an AMD Athlon-64 3000+ running Gentoo. I
don't see any obvious differences in /var/log/messages or in dmesg output
when the problem occurs vs. when it doesn't, but I do get a "cx8802_timeout"
message whenever MythTV tunes the card.
So, has anybody run into anything like this before? I may start futzing with
using v4lctl and various options as a channel-change command if I don't get
any replies, but if somebody's got a ready-made solution, or even a
better-educated guess at a solution, I'd love to hear it!
Once I solve the problem or give up on trying to solve it I'll upload a
description of the card, and the steps needed to get it working in MythTV, to
Thanks for any replies.
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