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Video jitter : PC -> HDMI cable (15m) -> Samsung LED 46 (1 Viewer)

Alonzzo2

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Sep 2, 2012
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Alon
Hi,
I've searched everywhere for a solution to my problem and can't seem to find it:
My setup:
i5 750, gtx 460 1G, Win 7 (also tried Win 8) 64 bit, mini hdmi adapter to hdmi -> hdmi cable (15m which costs around 80$) -> Pioneer 521k receiver -> Samsung UA46C6900 LED tv
My problem:
When playing a video (720p/1080p) from my PC to my TV, especially when the picture is panning, the video stutters a bit. some people don't notice it until I point it out to them, but I sure do.
What i've tried to fix this:
used wmp12, bsplayer, mpc-hc, xbmc. switched codec pack from K-Lite to Shark007.
checked that the cable is ok - connected it to my set top box which outputs 1080i (i'm not sure about the i) and the video ran smoothly.
changed the frequency of the signal - tried 23, 24, 29, 30, 59, 60hz. some of which were in interlaced mode.
tried different movies of course.
NOTHING WORKS! - and it runs smoothly on my 22" pc monitor.
I think the most significant thing I did trying to resolve this issue was playing around with the frequency - I've noticed the problem being a lot worse when I changed the frequency to some of the other frequencies. the frequency in which the video stuttered the least was 60hz.
I've read somewhere that this problem is caused when the player (or the tv) tries to synchronize the sound with the video and is called jitter? I'm quite confused right now and not even sure what the problem is.
Does anyone have a suggestion?
I'm really desperate.
Thanks!
 

Gregg Loewen

Founder, Professional Video Alliance
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not sure....
Try a BD player vs your PC and then you can isolate the cause.
ensure all the processing frame interpolation stuff is turned off on the samsung.
This is a good example of why I do not recommend PC systems as part of theater system (way too many variables).
 
K

Kevin Collins

I've read somewhere that this problem is caused when the player (or the tv) tries to synchronize the sound with the video and is called jitter? I'm quite confused right now and not even sure what the problem is.

Jitter is typically related to audio. It came frequently with S/PDIF cables, but could happen across a variety of cable types. In analog to digital and digital to analog conversion of signals, the sampling frequency is normally assumed to be constant. Samples should be converted at regular intervals. If there is jitter present on the clock signal to the analog-to-digital converter or a digital-to-analog converter then the instantaneous signal error will be introduced.

Judder is the term more frequently used when movies that were shot on film (i.e. 24FPS) are presented on a display that can only do a 30FPS (or a multiplier of it).

I'm not sure what type of video content you are using from your PC. Is it DVD, Blu-ray, streaming media, camcorder video?

Depending on what the source was actually shot in (24FPS typically for film, though some video is shot at 24FPS or 30FPS for video) and what your display(s) can display back at will determine if you see judder or not. If you are watching movies (DVD, Blu-ray) that were shot at 24FPS, and you display can only display a multiple of 30FPS you will see judder. Judder occurs from 3:2 pulldown,


What is 3:2 pulldown?
How do you stretch 24 frames of film onto 30 frames (60 fields of video)? You improvise. Basically, we stretch four film frames into ten video fields. Even if we simply doubled the film frames, we would still only have eight fields. So, we have to create two brand new video fields. In order to get the motion looking fluid, these new video fields are constructed using two different film frames. Confused? Take a look at the image below.


d62cd48c_32Pulldown.jpeg


I suspect that is what is happening. To get around the problem you need to match the source FPS to what your display can output for FPS. Also, components in between can also introduce 3:2 pulldown problems.

However, I agree with Gregg, watching DVD or Blu-ray from a PC adds a number of variables that can cause this problem.
 

Alonzzo2

Auditioning
Joined
Sep 2, 2012
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5
Real Name
Alon
Just wanted to say thank you for all you guys and let you know that i've finally stopped messing around with this issue and watching movies using xbmc and without clone or extend on the display - the only active screen is the tv when i'm watching movies.
In the xbmc configuration i've activated dxva and i've updated my directx engine to v11.
Now the video still stutters but its very hard to notice it so it's ok... no one notices it except me, and that too happens on rare occasions.
Thanks!
 

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