[mythtv-users] Hd Pvr playback jitter

Don Brett dlbrett at zoominternet.net
Sun Jul 18 14:08:46 UTC 2010

MarcT wrote:
> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org
> [mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Don Brett
> Sent: Saturday, July 17, 2010 7:40 PM
> To: MythTv-Users
> Subject: [mythtv-users] Hd Pvr playback jitter
> I have a new installation of MythDora-12 (thanks again for the blaster 
> help), with a nasty jitter on playback.  From what I've read, it ought 
> to be working pretty well, but it's not, as if I've missed something 
> major.  Actually, I tried playing a mythtv recording with VLC Media 
> Player and it worked OK; the video seems to be fine.  Here's what I  have:
> Video board - MSI - GeForce 8400 GS
> Nvidia driver version - 195.13.15
> Current Video Playback Profile - VDPAU Normal
> Bitrate setting - all default (I played with them, but it didn't make 
> any difference)
> There's a new version of the HdPvr firmware, but from the descriptions, 
> it didn't sound like it would help, so I haven't installed it yet.  Any 
> suggestions on what to look for?
> PS - Here's a couple of clips I captured, but they don't jitter the same.
> http://users.zoominternet.net/~dlbrett/1011_20100717180557.mpg
> http://users.zoominternet.net/~dlbrett/1011_20100717183742.mpg
> _______________________________________________
> Don,
> Which deinterlacing method do you use? Also is the video HD or SD? Sorry I
> didn't download the videos.
> I'm capturing and playing from a diskless ATOM/ION based FE/BE combo to a
> NFS share.
> Playback is fine, until the ION starts to overheat. This heatwave is doing
> bad things to my system, it is fanless as well, and the wife says we don't
> need an AC to cool off the house.
> MarcT
> _______________________________________________
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> mythtv-users at mythtv.org
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I haven't paid much attention to the temperature; the box has seven 
fans, including one on the video board.  At the moment it's 63 degc (145 
degf).  The slowdown threshold (reported by nvidia-setttings) is 125 
degc, so I doesn't look like I'm very close to it.

I didn't know I had to pay attention to the de-interlacing settings.  
Good catch, that seems to make quite a difference.  It's using VDPAU 
rendering, and I assumed the default settings would be close enough, but 
maybe not.  I just switched the deinterlacers to "One Field (1x, HW)" 
and all the jitter went away.  I doubt this is how we want to leave it, 
so I'll do some experimenting with the settings.

Thanks for the tip, I think we're on the right track now.


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