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video stutter: 5200 FX playback
http://forum.linhes.org/viewtopic.php?f=2&t=8946
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Author:  virusdoc [ Sun Mar 12, 2006 10:08 pm ]
Post subject:  video stutter: 5200 FX playback

I'm having an issue with video playback, where I have normal smooth video most of the time, but a dropped frame, slow down, or "stutter" every 30-45 seconds. I'm running the latest release of Knoppmyth (R5A30.2) on the following system:

Gigabyte GA-7VAXP (via KT400), Athlon XP 2100, 768 M RAM
Nvidia GeForce FX 5200 AGP card, TV out composite
686 kernel modules selected at auto install
Default nVidia TV-out XFree86 config file

I am recording most shows in the default recording profile, which is pretty high bitrate as a recall (4500Kbps?), at 640 x 480 resolution. As far as playback settings go, I've tried with and without XvMC, with or without OpenGL, and with either Bob (for XvMC) or Linear deinterlace filters. Nothing seems to make a difference in the frequency or severity of stutters.

I know this hardware is capable of smooth, uninterrupted playback, b/c I had it running MythTV 0.17 in Fedora Core 3 for over a year before a HDD died. But I don't know how it was configured differently on that system, since I can't access the old files.

Can anyone suggest other settings that I should modify? Thanks in advance.

Author:  gr8nash [ Mon Mar 13, 2006 12:11 am ]
Post subject: 

odd.. can you tell is the CPU topping out? also if its a modline type issue maybe watching a movie in mplayer might let us know? do avi movies cause this?

Author:  virusdoc [ Mon Mar 13, 2006 7:41 am ]
Post subject: 

Running top from SSH while playing a program, my CPU utilization is under 20% even when "stutters" are detected. This is what I would expect.

Upon further evaluation, I've determined that the stuttered frames are in fact encoded in the recorded stream. A frameshot is linked below, where you can see that the lower right of the screen is superimposed with a single, spatially shifted offset frame. I guess this means what I really have in an encoding issue. I forgot to mention in my first post that I'm using a Hauppauge PVR-250 encoding card, with hardware MPEG-2. Suggestions?

http://www.virusdoc.net/archives/stutter.html

Author:  gr8nash [ Mon Mar 13, 2006 10:18 am ]
Post subject: 

well if you think its encoded that way.. (maybe play the nuv file in mplayer to confirm?) then you get to play: SWAP THE IVTV version game!!!! Cant say i miss the IVTV games.. =/ back when i was using the pvr250 i would always be running differnt versions to find one perfect one.. never did find it. =)
thats where i would start after your sure its encoded that way.

Author:  virusdoc [ Mon Mar 13, 2006 11:09 am ]
Post subject: 

gr8nash wrote:
well if you think its encoded that way.. (maybe play the nuv file in mplayer to confirm?) then you get to play: SWAP THE IVTV version game!!!! Cant say i miss the IVTV games.. =/ back when i was using the pvr250 i would always be running differnt versions to find one perfect one.. never did find it. =)
thats where i would start after your sure its encoded that way.


Yes, it's all coming back to me now. I had to use three different IVTV drivers under Fedora Core 3 to get my card to work correctly, something I had forgotten. Yuck.

I'll confirm the encoded frame stutter in mplayer as you suggest, but I'm pretty sure it's in the stream. I was able to pause and rewind frame by frame and find the precise abberancies at the same time codes. It's hard to imagine that being a playback issue--I would expect playback errors to be more random.

Thanks for the advice! I'll update as I learn more.

Author:  virusdoc [ Mon Mar 13, 2006 11:32 am ]
Post subject: 

gr8nash wrote:
back when i was using the pvr250 i would always be running differnt versions to find one perfect one.. never did find it. =)


Out of curiousity, what card are you using now? It may be easier to switch cards than to troubleshoot drivers...

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