Stuttering Video in Recordings

[Aydan]

Hi there,

I use GBPVR for recording only. I noticed problems when other programs are transferring large amounts of data. This causes the video to have missing chunks. I think this has to do with buffer overruns, where the data is not fetched fast enough from the buffers. Now I'd like to know if this is a driver problem or a gbpvr problem. I'm using three Hauppauge PVR150. Recording on all three simultaneously is no problem unless I move a file or do some other IO-intensive stuff, which can not always be prevented. It might help if the recording thread would have higher priority.

CU
Aydan

[csy]

Force gbpvr recording service to high priority in config.xml in the gbpvr directory.

<ForceHighPriorityRecordingService>True</ForceHighPriorityRecordingService>

[Aydan]

Thanks for the tip. I'll tell you if it works in a few days.

Aydan

[lingenfr]

Force gbpvr recording service to high priority in config.xml in the gbpvr directory.

<ForceHighPriorityRecordingService>True</ForceHighPriorityRecordingService>

I have a similiar problem with stuttering in LiveTV. I looked through the config.xml file, but could not find a similar entry for LiveTV. Is there one? Thanks.

[wtg]

ligenfr,

Are you also an MVP user? If so, the Next Recordings panel in the skin used by your MVP client(s) can cause the PC to stutter during Live TV, approx. every 5 seconds. The more MVPs you have and the slower your PC, the more pronounced. I'm using an AMD 2500 w/3 MVPs and it's definitely noticable.

If you think this is what's happening to you, and if it is you should see a spike in CPU usage every 5 seconds using Taskman or perfmon, try editing skin.xml in the skin's main menu directory and set the Next Recording special element's visible attribute to false. This made a huge difference for me.

[lingenfr]

Nope, I am not using MVP. Should I make the change anyway?

[djtaylor]

Nope, I am not using MVP. Should I make the change anyway?

No point. What you can do is run the gbpvr programme at a higher priority, that should sort it.

I noticed that the Hauppauge wintv runs without stuttering but that it also runs at above normal priority, gbpvr by default runs at normal.

David.

[csy]

LiveTV is a record/playback combination, so <ForceHighPriorityRecordingService> will prioritise CPU time to the recording component of LiveTV, but you are correct there is no equivalent setting for the playback component.

Studdering on playback is commonly caused by loss of clocking (frame sync) or poor MPEG2 motion compensation decoding (decoding of MPEG2 "P" and "B" frames).

For users who use the default BOB deinterlacing there is a well known clocking problem with the DirectX9c quartz.dll, with the work-around being to drop back to the DX9b quartz.dll.
http://support.microsoft.com/default.asp...-us;885354
Also some decoders use proprietary clocking mechanisms from their players (eg WinDVD) which have problems when used separately to the player. IMO for best clocking sync, if you have a Nvidia video card I recommend the Nvidia Purevideo decoder, and if you have an ATI video card, I recommend DScaler5 (ver008 or later).

I have also noticed that the Nvidia DXVA motion compensation does not work very well on interlaced MPEG2 (eg LiveTV) which produces jumping effects on fast moving objects. You can minimize (not eliminate) this effect by tweaking your TV-card MPEG2 encoder to use fewer "P" and "B" frames. On my ATI550 card I have selected "12GOP,1P,1B", but note this reduces the compression therefore increases file size on recordings.

[egold]

I have a nvidia 6600 and using the nvidia pure video decoder. what is "p" and "b"'s I havent teaked the video drivers yet just running at application controled. what should I be looking for?

thanks

[lingenfr]

Well, I have taken all of the advice. I created a batch file to start it in above normal priority (that fixed most all the stuttering). I have an ATI 9600 in my notebook, so I downloaded DScaler5 and switched to that. I also made the change to my config.xml. Thanks.