Help with smooth video playback (jitter/stutter troubleshooting) (1 Viewer)

[mrceolla]

Thanks again for your reply.

Why can PC video cards NOT lock the output to a video source like STBs, DVD players and VCRs? This is the part that puzzles me the most.

I attempted to create custom resolutions with the Nvidia control panel but had no luck. No matter what I set it to the measured refresh rate was always showing 60.00##... So I started looking for other solutions.

That brought me to PowerStrip. I was able to create custom timings in PowerStrip with did finally effect my measured refresh rate. After much trial and error of incrementing front porch, back porch, pixel clock, vertical refresh rate and one other thing I forgot, I was able to dial in 59.940 for vertical refresh frequency. At least that's the number PowerStrip reported. I went into Media Portal and played back some video and enabled the overlay. It now reported the measured refresh to be 59.943###. Pretty damn close, right? Stuttering/jitter is now very few and far between. The NST is somewhat regular. It will change rapidly but in very small increments. It will sometimes rise or lower very slowly but rarely reaching the threshold to cause a stutter. But every once and a while there is a seemingly large hickup. Not sure where that's coming from yet. So far this seems the best solution for me with TV and 5.1. Are you aware of any caveats with PowerStrip?

What should that info overlay look like if everything is in perfect harmony? What should the numbers be and what should that graph look like?

What is Stall?

Does everyone with an HTPC experience these timing issues? Do most just not look for or notice them?

Is there hope for the near future that these troublesome HTPC timing issues will be resolved?

Thank you all for helping me get this far but I'm not through yet. I'm still going to strive for perfection although I'm not sure I'll ever achieve it. We'll see. I will continue to post my trials and results here and will of course gladly take any additional suggestions/advise.

Mike

 

[tourettes]

Why can PC video cards NOT lock the output to a video source like STBs, DVD players and VCRs? This is the part that puzzles me the most.

PCs cannot since they don't have single audio & video clock source (see the response for the last quote).

Does everyone with an HTPC experience these timing issues? Do most just not look for or notice them?

Majority of the people wont notice, care or understand

Is there hope for the near future that these troublesome HTPC timing issues will be resolved?

There is a beta audio renderer available that will try to sort out the GPU / audio chip clock drifting and refresh rate mismatch - https://forum.team-mediaportal.com/...renderer-better-video-playback-quality-84441/

Other sollution would to request GPU maker's to use one single HW timer source for the both audio and video part timing.

 

[Owlsroost]

The big, occasional hiccups may be caused some other process in the PC taking a lot of CPU time briefly, or drivers/hardware causing high interrupt latencies - try running DPC latency checker to check.

If PowerStrip works for you, then just carry on using it (it doesn't work on more modern nVidia cards like my 9500GT, as far as I know).

Don't worry about the actual NST values etc - if the graph lines are reasonably flat then things are working as they should.

Tony

 

[mrceolla]

Hi folks,

Thanks again for your helpful input. I hope you all had a great holiday weekend. Mine...not so much. I got robbed. Needless to say that is going to put a damper on my htpc project for a few weeks while I try to sort everything out and obtain new electronics. I just thank god they didn't take my desktop computers which contain years of work. Time to look into offsite backup.

I shall return with progress updates and I'm sure more questions. In the meantime, have a very Happy New Year!

 

[mrceolla]

Hello,

I'm still dealing with my robbery and haven't had a chance to get back to my HTPC project. But I have a questions regarding the separate audio and video clocks discussed earlier.

If I get a video card with HDMI output which also carries the audio, will both the audio and video streams use the same clock on the video card? Will this ensure the output refresh rate can match that of the TV without the need for things like PowerStrip or Reclock?

Thanks,
Mike

 

[tourettes]

I'm still dealing with my robbery and haven't had a chance to get back to my HTPC project.

Sorry to hear that it has caused so much trouble for you.

But I have a questions regarding the separate audio and video clocks discussed earlier.

If I get a video card with HDMI output which also carries the audio, will both the audio and video streams use the same clock on the video card? Will this ensure the output refresh rate can match that of the TV without the need for things like PowerStrip or Reclock?

Unfortunately today's GPUs still seem to use different HW clock source for audio and video. This is most likely caused by the fact that ATI & Nvidia are both bying the audio implementation as a "ready silicon sollution" (they just integrate it into the GPU) and that has own clock. Please someone correct me if I'm wrong but at least it seems that for example Nvidia GT220 still has separate source for video and audio clocks since they are drifting apart.