[mythtv-users] Shuttering sound with PVR-250

[Yan-Fa Li]

Your AMD is practically about 400% faster than the P3, so you're going 
to have work a bit.  Maybe you're swapping under load, you don't say how 
much mem you have, have you checked that ?  Verify what DMA the drive is 
running at.

hdparm -i /dev/hda

will tell you if it's running in dma mode and what mode.  For example:

  Model=IC35L120AVV207-1, FwRev=V24OA66A, SerialNo=VNVD09G4CTX3DT
  Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
  RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=52
  BuffType=DualPortCache, BuffSize=7965kB, MaxMultSect=16, MultSect=16
  CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=241254720
  IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
  PIO modes:  pio0 pio1 pio2 pio3 pio4
  DMA modes:  mdma0 mdma1 mdma2
  UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
  AdvancedPM=yes: disabled (255) WriteCache=enabled
  Drive conforms to: ATA/ATAPI-6 T13 1410D revision 3a:  2 3 4 5 6

See the asterisk near UDMA5.  That's the speed it's running at.  Maybe 
your drive isn't enabling DMA for some reason.

That's a pretty old box, so it's probably running at UDMA33, which 
normally isn't a problem but might be in your case.  If you can afford 
it, drop a $20 UDMA100 card into a spare PCI slot and see if that helps.

Did you turn off X ?  Have your disabled all unecessary daemons ?  What 
kind of network card are you using ?  Maybe it's consuming too much 
processor.  Basically when you use an old PC you have to do a lot of 
fine tuning.  Try compiling some of your components specifically for P3 
instead of i386 or i686, and turning on -mmmx as an optimization.  I 
always like to install an i686 optimized glibc on a pentium class box as 
this speeds up all user space programs :)

Yan

avarakin at optonline.net wrote:
> Hi,
> 
> I had a perfectly working Myth setup on my Athlon XP 2000+ PC.
> 
> I built a new headless Myth backend using old 667MHz  PIII PC and I am getting shuttering sound and incomplete recordings if I record and watch at the same time. 
> I watch recordings using a different PC.
> If I record a program and then watch it later, all works fine, so there might be some kind of competition between recording and playing thread of the backend.
> 
> When I play a recording with damaged sound and do a seek, then sound becomes normal for a few seconds and then shutters again.
> 
> 
> My environment is:
> Debian unstable
> Myth 0.16 from repository
> PIII 667MHz
> stock kernel 2.6.7
> PVR-250 with CK driver version 99
> 
> Thanks,
> Alex