[mythtv-users] stutter while recording two programs at once

[Tony Lill]

Brad DerManouelian <myth at dermanouelian.com> writes:

> I've got an AMD64 box with a SATA II drive formatted as JFS dedicated  
> to recorded programs. music, photo, videos are on a separate SATA  
> drive and the system runs from a PATA drive - all are 7200 RPM with  
> 8MB buffers.
>
> I've got a PVR-350 and an HD-5500 card in the box which is also my  
> frontend. I'm getting weird stuttering when recording on both tuners  
> at the same time. The HD stream looks perfect but the stream from the  
> PVR-350 will show a single frame from about a second before the  
> current position. It happens intermittently but often enough to be  
> REALLY annoying. I've found that it's in the recording this way since  
> the rogue frames happen at the same place when I play back every  
> time. I have a feeling it MIGHT only be happening when watching a  
> program and recording two others at the same time. I had anticipated  
> 3GB/sec on the SATAII drive would be enough bandwidth to watch 1,  
> record 2. Is this not the case? Is there a good way to test? Do I  
> finally need to submit and start transcoding every program I watch  
> and deal with sub-par quality?
>
Are you getting any messages from the ivtv driver about your
application not reading fast enough? Look in
/var/log/messages. 

There's a known problem where database access slows
things down enough to cause dropped frames. It's more likely to happen
in the first minute of the recording, 'cause it hits the database more
often then.
--
Tony Lill,                         Tony.Lill at AJLC.Waterloo.ON.CA
President, A. J. Lill Consultants        fax/data (519) 650 3571
539 Grand Valley Dr., Cambridge, Ont. N3H 2S2     (519) 241 2461
--------------- http://www.ajlc.waterloo.on.ca/ ----------------
"Welcome to All Things UNIX, where if it's not UNIX, it's CRAP!"