[mythtv-users] Transcoding advice -- stuttery video, tearing, nausea

[Brian Wood]

On Oct 19, 2006, at 4:27 PM, Pete Cap wrote:

>
> Second, if I try to transcode while the box is recording, the  
> resulting recording will be stuttery.  I'm using a PVR-150 which  
> should be doing all the encoding with little or no hit to system  
> resources that I'm aware of; is transcoding THAT intensive?
>

You can change the niceness level of the transcode jobs, you might  
try increasing the niceness (lowering the priority) and see if that  
helps. You don't mention how much CPU you have available, if it's  
very limited you might be getting into trouble there.

Or your problem might be with disk access, not CPU. Although the PVR  
does the encoding it still has to be able to write to the drives  
system at a fairly good rate.

I had a problem with stuttery recordings if I tried to make two of  
them at once, this was solved by adjusting the PCI latency values of  
my drive controllers, I can now make 4 at once with a transcode job  
running without problems.

Check out:

http://www.mythtv.org/wiki/index.php/PCI_Latency

But as always YMMV, some folks have had no luck at all with latency  
adjustments, just depends on whether that is your weak link I guess.

You might also use hdparm to see if your drives are performing up to  
par (DMA enabled etc.).