[mythtv-users] Big Plea For Help

[Mark Garland]

Hi all,

 

I've been battling now for the last 3mths to get my mythtv setup working,
and whatever I try I still can't see to get there.

I'm don't think it's the myth software - it's probably the underlying OS
configuration, so any tips or suggestions are really welcome.  

My latest theory is to just wipe the HDD and try again, as I really have run
out of things I know to try.

I appreciate this is a long post, but any help would be gratefully received!

 

My setup is a 5050e CPU, GA-MA78GM-S2H (780g video (radeon HD 3200), with
realtek ALC889A sound), 4GB Ram, 2 DVB-T capture cards (1xNova-TD-500(dual
tuner) and one Nova-t (single tuner)), and a single 7200rpm 1TB HDD.  The
filesystem is ext3, with a xfs partition for the video files (apparently
good for deleting large files and offering smooth data transfers).

I'm running Ubuntu 9.04, with KDE installed on top, and a combined
frontend/backend running myth 0.21.0+fixes19961-0ubuntu8 installed out of
the repositories.  I keep the system up to date.

 

The main issue I get random locking - either during recorded shows, channel
changing, or live tv.

Sometimes it locks and tells me that it is "Timed out waiting for free video
buffers", sometimes it's a collection of
"RingBuf(/video/1001_20090717183822.mpg): Waited x seconds for data to
become available...", sometimes the UI locks but the video keeps playing
with no sound with masses of "AddAudioData():p1: Audio buffer overflow,
audio data lost!".  Usually there are "prebuffering pause" and "Prebuffer
wait timed out 10 times".

Generally, after 5mins or so, I'm taken back to the menus, but during that
time the frontend UI is unresponsive.

 

I don't think it's a CPU problem.  The dual-core CPU often scales back from
2.6Ghz to 1Ghz, and rarely goes about 50% of that, even when recording,
watching and commsflagging.

I don't think it's an IO problem.  Iostat says the harddisk rarely goes
about 30%, and vmstat rarely goes about 5 for IOwait..  As a test, I ran a
load of really intensive HDD tasks to take it to 100% and myth ran fine.

 

I've currently got my ring buffer set to 96mb (the max) and this helped
things, but I suspect it's smoothing out the problem rather than solving it,
as most people run it at just 4mb (says the docs).

 

With audio,

Ubuntu comes with pulseaudio.  I removed/disabled that, as recommended here:
http://www.mythtv.org/wiki/Configuring_Digital_Sound

I'm using ALSA which worked fine.  The resolve the above, suspecting an
audio problem, I went to www.alsa-project.org <http://www.alsa-project.org/>
and downloaded the latest 1.0.20 version that said it specifically supported
my chip.

Settings wise, output device is ALSA: default, Mixer is ALSA: default.
Happy to supply more.

 

With video,

Drivers for the 780g are a pain.

I'm currently running the xf86-ati-radeon opensource driver, and get pretty
good results.

Last night, (thanks Steve Milner for the tip), I tried version 9.6 of the
proprietary fglrx driver and followed
http://www.mythtv.org/wiki/ATI_Proprietary_Driver.  This worked well, but
did give a lot of tearing which apparently cannot be resolved.

I've also tried the xf86-ati-radeonhd driver, which gave pretty bad
performance.

 

So, where should I go from here?  Do we think this is still an audio
problem?  Or a video problem?  How do I tell?  Could KDE be affecting it?

Have I just bought nasty hardware for this job?  Don't really want to, but
will I ever get this working, or will I end up dumping the board and getting
an NVidia based system?

Does anyone else have a 780g?  or ALC889A (or close) sound?  Does it work
reliably for you?  How do you get it to work?

 

Any help/advice appreciated.  Thanks in advance,

 

MG

-----

"The most overlooked advantage of owning a computer is that if they foul up
there's no law against whacking them around a bit."

 

 

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