[mythtv-commits] Ticket #897: RealTek ALC880 Issues (Audio Buffer
Overflow)
MythTV
mythtv at cvs.mythtv.org
Fri Dec 30 08:03:00 EST 2005
#897: RealTek ALC880 Issues (Audio Buffer Overflow)
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Reporter: ian.bonham at gmail.com | Owner: ijr
Type: patch | Status: new
Priority: major | Milestone:
Component: mythtv | Version:
Severity: medium |
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Hi Robert,
Just a quick note you may want to include mate, as I have had this problem
and spent hours on it. I was unable to find anything on the web about it,
so the cure was trial and error (for my setup anyway), and it seems it's a
growing problem.
I have an MSI mobo, 915 series, with a P43.2ghz and 512gb Ram. When I
tried to play or record live TV I had major issues with stuttering video
and choppy sound. This was in Myth0.18.1 on Debian (KnoppMyth) Kernel
2.6.13.2-chw-3 #1 SMP. I was able to recreate the issue using cat
/dev/video0 > ./test.mpg, so I knew it wasn't down to Myth as the stream
dump (from a Hauppauge PVR150) was knackered as well. However, Myth was
outputting bugs of "Prebuffering Pause" and "Audio Buffer Overflow,Audio
Data Lost!". It seems a lot of people are having the same prob.
It seems it was the sound so upgraded to Alsa1.0.11rc1, which reportedly
solved a lot of the ALC880 problems. Still the same tho, so I downloaded
RealTek's driver from their site. Still the same.
So I started to look at OSS. Reading their Doc's it states their driver
works with all AC97 chipsets. This made me think, in the BIOS there is an
option to switch the onboard sound between Disabled/AC97/Azalia. I checked
my BIOS and it was in Azalia mode. I switched it back to AC97, then
brought Debian up and ran alsaconf again just to check any settings were
reset.
MythTV and recording now works perfectly. It seems there is a bug
somewhere in the ALSA drivers for the Azalia mode of the ALC880. Running
it in AC97 mode means alsa can talk perfectly to it. This simple fix
suddenly got Myth working perfectly and I'm really impressed with it. Glad
I wiped M$'s MCE now! It's worth noting that I didn't try the OSS drivers
in the end. As of today (30/12/05) it's still noted on OSS docs as
experimental, and as alsa runs nicely with AC97 mode I didn't bother
opening the OSS can of worms!
Hope that helps someone else out, dunno if you want to stick it in the
docs somewhere, but a simple BIOS tweak saved my buying an SB Live! :)
Happy New Year to all the Myth team, thanks for a great project,
Bon
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Ticket URL: <http://cvs.mythtv.org/trac/ticket/897>
MythTV <http://www.mythtv.org/>
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