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

[Steven Adeff]

On 8/29/06, Tony Lill <ajlill at ajlc.waterloo.on.ca> wrote:
> 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.

it may also be a pci latency issue, I had similar occur with a PCI ATA
card I'm using for part of my RAID array once I changed the latency
this went away.

-- 
Steve
Before you ask, read the FAQ!
http://www.mythtv.org/wiki/index.php/Frequently_Asked_Questions
then search the Wiki, and this list,
http://www.gossamer-threads.com/lists/mythtv/
Mailinglist etiquette -
http://www.mythtv.org/wiki/index.php/Mailing_List_etiquette