[mythtv-users] Artifacts in PVR-150 recordings

Sage sage at gypsycaravan.com
Sun Jul 2 06:40:10 UTC 2006


I'm running MythTV 0.19-fixed on Ubuntu 6.06 (Dapper Drake), kernel
2.6.15.  My hardware is as follows:

MSI K8NGM2-FID motherboard, with onboard Nvidia Geforce 6150 TV-out
2 GB of DDR266 RAM
Hauppauge PVR-150
2 500GB SATA drives in software RAID1 for root partition
1 200GB IDE drive for recordings

I am having problems with my recordings.  Sometimes when I play back
recordings there are some pretty horrendous artifacts -- big, blocky
jumbles on the screen, particularly when there's a lot of motion.  It
happens frequently when watching live tv.  What are the likely causes?
 I have a few suspicions:

1. It could be a problem with the PVR-150 drivers or firmware.  Can
other PVR-150 users comment on this?  I'm using the latest ivtv driver
release, 0.46.
2. The swap partition is on the 200GB IDE drive that I'm using for
recordings.  Could this be the culprit?  Swap usage remains pretty
steady at 18396k, and I have 2 GB of RAM...
3. I'm thinking it could be possible that the various playback methods
supported by MythTV aren't properly decoding the recordings; the
PVR-150 has its own hardware encoder, but I'm decoding in software...
is this a possible cause?

Note that I am not using XVMC for playback; I think the onboard GPU
isn't able to keep up with scaling a 720x480 recording to 800x600 with
deinterlacing; the playback is smoother when I use the CPU.
Regardless, the artifacting occurs with or without xvmc.

Note that not all recordings do this, but it does happen frequently.
How likely are the above possibilities?  Are there any cursory items
in MythTV setup I should be looking at to help resolve this?


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