[mythtv-users] poor quality tv from pcHDTV (dvb)

[Ian Forde]

On Thu, 2007-07-12 at 20:28 -0700, Mark Fischer wrote:
> I'm having very poor quality tv from my pcHDTV 3000 card.
> About my system:
> AMD 3800+ X2 64 bit
> 2x1GB PC3200 dual channel memory
> 250gb SATA Hard Drive WD Caviar
> pcHDTV 3000
> Nvidia GeForce 6600 on PCI Express 16X
> MSI K8N Neo4 Platinum mainboard
> 
> I've been testing directly with mplayer like:  mplayer -nosound dvb://
> I've tried all the -vo options. Of those that "work", the image is
> highly pixelated and it seems to be rendering very slowly.  I believe
> this has to the with the capture card because I've played back an HD
> trailer of Pirates of the caribean with mplayer and it plays back
> fine.
> 
> My capture card is fed with a digital cable signal. I've read the wiki
> on these topics:
> http://www.mythtv.org/wiki/index.php/Working_QAM_cable_layout
> http://www.mythtv.org/wiki/index.php/Adding_QAM_Channels_For_HDTV_Tuner_Cards
> 
> azap output has sporatic loss of locks:
> 
> status 1f | signal f758 | snr 217b | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal fa17 | snr 1995 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal f51b | snr 2204 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal f7c2 | snr 2197 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal f863 | snr 20e1 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal f5b5 | snr 216d | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 00 | signal f3b9 | snr 213d | ber 00000000 | unc 00000000 |
> status 1f | signal f582 | snr 21ee | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal f07c | snr 21f5 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal c7b0 | snr 2144 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 1f | signal f7f8 | snr 21f5 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
> status 00 | signal f5b5 | snr 21e6 | ber 00000000 | unc 00000000 |
> 
> and mplayer will sometimes reports errors like these:
> a52: CRC check failed!
> a52: CRC check failed!
> a52: error at resampling
> a52: CRC check failed!   10.304 ct:  0.037  22/ 22 20%  1% 1683.9% 22 0
> 
> From what I've read, the standard channels are not encrypted (Comcast
> in San Francisco).
> 
> Any ideas would be greatly appreciated.

I've had similar problems with both an Athlon 64 3200+ and an Athlon 64
3800 X2.  Turns out that if I have *any* CPU load when recording, I get
crapped-out recordings.  But if I capture then playback later, all works
out fine.  There are notes in the list archives about this being caused
potentially by power supplies, PCI latency, APIC, and various other
things.  My suggestion would be to put the pcHDTV 3000 in a separate
non-frontend, non-job-running system (something small and not very
powerful, as CPU isn't needed to record) and call it a day... unless, of
course, you find the source of the problem... ;)

	-I