Jitter / stutter / jerky playback issue with HD TV

[rafe]

Problem: there is jitter or stutter in the image when watching HD TV (live or recorded). With Channel 10 the problem is particularly bad with frames being dropped seemingly at random, making it nearly unwatchable. With the other channels the image seems to jerk slightly at regular intervals of about a second. This is mainly noticeable with long panning shots, for instance on the football or in action movies. Once you do notice it, the problem is quite aggravating. To top it all off, I'm not convinced the image quality compares with my cheap old HD set-top-box.

Here's my rig: AMD BE-2350 CPU, AN-M2HD motherboard, 2GB DDR2 RAM, TinyTwin USB dual HD tuner, 500GB Samsung HD, SH-203B Samsung DVD drive, PCI Wi-Fi card, Antec 2480B case, 32" Sony Bravia LCD TV, running Vista Home Premium 32-bit version, and the AnyDVD region unlocking program.

I have tried all sorts of things, but with no success:
- Applying all the hotfixes listed for Vista on the sticky thread on this forum.
- Updating the nForce and graphics drivers for my motherboard.
- Updating DirectX.
- Ensuring Vista and Vista Media Center (VMC) both run at the same resolution and framerate.
- Changing resolutions (picture quality seems better at 720p, but the jerkiness is less noticeable at 1080i - I think because the frequency of frame drops goes up making playback appear smoother).
- Purchasing Nvidia's PureVideo software (it would be great if they made it clear on their site that their software doesn't support Vista...) and using VMCD.exe to make VMC use the Nvidia decoders. This results in increased image quality for still scenes, but terrible ghosting for movement. I suspect the Nvidia decoder is doing a bad job of de-interlacing in software.

I have a few other whinges about VMC, but if anyone can help me fix my TV image issues I would be really, amazingly, superlatively grateful!

Cheers,
-- Ralph

[as0l0]

i have the same issues, but no answer.

just wanted to add that you must feel royally robbed for buying the purevideo software.

[logifuse]

Hi Ralph,

Me again.

My results with 720p @ 50Hz are nothing short of superb, so your stuttering picture is a big contrast. When you set the res within VMC, are you taking the list all modes option & then choosing 1280x720@50Hz, or are you just selecting the 720p option? I think the 720p option actually gives you 1280x720@60Hz.

Also, I assume that you've got overscan with your TV (edges cut off)? If so, select TV instead of flat panel during the TV setup.

Test material: grab some of Today or Sunrise & use the scrolling ticker as your 50Hz test. Don't use recent episodes of House & Life because Ch 10 stuffed the conversion, so they jerk @ 50Hz no matter what.

Also, using some 3rd party software to playback

Image quality: have you switched from RGB to YCbCr444 in the HDMI/Digital color output section of the Nvidia CP?

If the stuttering problem isn't the 50Hz thing, try removing your wifi card for a test. For some reason they often cause trouble - nobody really knows why - some sort of interference.

See how you go.

Justin

[rafe]

Hi Justin,

thanks again for a lightning reply!

- I will try again ensuring VMC is running 1280x720 @ 50Hz, although I think I have already given this a go.

- I will definitely try removing the Wi-Fi PCI card. Would disabling it from the Device Manager work or do I have to physically unplug it?.

- Your earlier advice to use the TV setting, rather than Flat Screen, and YCrCb, rather than RGB, worked exactly the way you said.

- The scrolling ticker of Today and Sunrise both jerk slightly at about 1Hz (I think this is also visible on panning shots).

- I downloaded the free trial version of PowerDVD and used VMCD.exe to make VMC use those decoders. However, trying to watch TV with these decoders would cause VMC to fail immediately with an error message. If you can give me any advice on using PowerDVD I would be very grateful as I really would like to use the PureVideo functionality on the motherboard.

Fingers crossed it's just the Wi-Fi card!

Thanks again,
-- Ralph

[logifuse]

Hi Ralph,

Not 100% sure whether disabling the WIFI card should be the same as removing it - you would think it would be.

AFAIK, the MS decoder does take advantage of the Purevideo hardware acceleration. I'm not sure about getting PowerDVD to work - I never liked its image (too soft) in MCE2005 & haven't bothered in Vista as the MS decoder works well for me.

The other thing I forgot to mention yesterday was to test the recordings by running them, through VideoReDo - this will quickly tell you if it's a tuner issue or not as it's stand alone (with it's own decoders) & it will tell you about (& fix) any stream errors. All good means a 50Hz issue (or something unusual like hard drive caching), numerous errors mean the jerkiness is from the tuner/signal.

Justin

[rafe]

Hi Justin,

if our paths cross I owe you many beers! I made the following changes:
- selected 1280x720 @ 50Hz;
- disabled my Wi-Fi card from Device Manager;
- selected the PowerDVD video decoder (but not the audio decoder).
Now I have what seems to be a flawless image on all channels. Ticker-tape displays on Today and Sunrise are completely smooth and Channel 10 is clear as a bell. I've been looking very hard to spot any glitches, but can't claim to have seen any yet.

I'll try going back to the Microsoft decoder and see how that performs. I'm currently using the trial version of PowerDVD, but I'd rather not spend yet more money unless it's necessary.

You have no idea how grateful I am for your advice!

All the best,
-- Ralph

[rafe]

Hi as0l0,

Nvidia have a 30-day returns policy, so I should get my money back. I wish they would make it much clearer on their web site, however, that their PureVideo software is not Vista compatible.

[jollster101]

Originally Posted by rafe

Hi Justin,

if our paths cross I owe you many beers! I made the following changes:
- selected 1280x720 @ 50Hz;
- disabled my Wi-Fi card from Device Manager;
- selected the PowerDVD video decoder (but not the audio decoder).
Now I have what seems to be a flawless image on all channels. Ticker-tape displays on Today and Sunrise are completely smooth and Channel 10 is clear as a bell. I've been looking very hard to spot any glitches, but can't claim to have seen any yet.

I'll try going back to the Microsoft decoder and see how that performs. I'm currently using the trial version of PowerDVD, but I'd rather not spend yet more money unless it's necessary.

You have no idea how grateful I am for your advice!

All the best,
-- Ralph

Which PowerDVD decoder did you use exactly?? Whenever I have looked to use it there has always been multiple choices and they never seem to look "quite right"

Cheers

[logifuse]

Not a problem.

When you spend ages working through the issues, you might as well share your experiences with others to try & save them some pain.

Now, are you willing to try & break it again to find the exact problem? I guess you'll know if it's the WIFI card when you re-enable it.

Justin

[rafe]

jollster101, two PowerDVD video decoder options came up, one mentioning something about home networking. I tried the other one, which works fine. Don't, however, try using the PowerDVD audio decoder: for me, at least, it crashes VMC as soon as I try to watch TV.

That said, following logifuse's advice, I'm going to try the Microsoft video decoder again and see which image I prefer. Apparently the MS decoder does exploit PureVideo hardware if it's available.

Cheers,
-- Ralph

[rafe]

Hi Justin,

now I've reduced the problem to three variables,
- 1280x720@50Hz or not
- Microsoft or PowerDVD video decoder
- PCI Wi-Fi card or not
there are only eight combinations, so I think I will try them all out the next time my wife has a girls' night out. But I'm going to set a restore point before I do anything!

Regarding writing-up the build and various fixes, I've tried to do just that here in case you're interested.

-- Ralph

[logifuse]

Great article.

In regards to cool 'n' quiet, I'm down to 1800RPM, but I think that's as low as the board will let the fan go. I'm going to try connecting the CPU fan to the SysFan1 connector & set the SYS FanEQ to CPU to see if I can get it lower, although I'm expecting to get the same result.

Justin