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Jittery Video?
#76
Guys, I am experiencing the same in case of horizontal pans on XBMC Live Beta1.

A question to all of you:
I also experiencing the same in case of the news feed which is scrolling horizontally at the main menu. It is jittery, not continous, and I think it is related to the same problem, isn't it? Are you experiencing the same jittery scrolling?
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#77
ashlar Wrote:First of all, I believe this thread should be about people who have refresh rates which are direct multiples of the frame rate of the material played.

If you play back 25fps material at 50Hz, 75Hz, 100Hz. If you play back 24 fps material at 48Hz, 72 Hz, 96Hz or 120Hz.

Otherwise, if you play 24fps material at 60Hz some judder is inevitable, due to the 3:2 processing. Although I'd freely admit that what I'm seeing at 60Hz is *really* bad judder too.

But the problem is that at direct multiples we should get silk smooth playback, no judder at all.

If you're primarily concerned with those using refresh rate multiples, then you should make a new thread concerning that. I'm concerned about the only refresh rate that should matter for htpc software - 60hz. If it can't output video properly at 60hz, it has no place in a home theater. The issues are probably related but let's not take our eye off the ball by focusing on the wrong issue.
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#78
mdaria510 Wrote:If you're primarily concerned with those using refresh rate multiples, then you should make a new thread concerning that. I'm concerned about the only refresh rate that should matter for htpc software - 60hz. If it can't output video properly at 60hz, it has no place in a home theater. The issues are probably related but let's not take our eye off the ball by focusing on the wrong issue.

Well you have to know that some judder at 60Hz is unavoidable. The only time perfectly smooth playback is possible is when the refresh rate is a multiple of the fps - if it isn't it can't possible have no judder because there will be a different number of refreshes for each frame.
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#79
mdaria510 Wrote:If you're primarily concerned with those using refresh rate multiples, then you should make a new thread concerning that. I'm concerned about the only refresh rate that should matter for htpc software - 60hz. If it can't output video properly at 60hz, it has no place in a home theater. The issues are probably related but let's not take our eye off the ball by focusing on the wrong issue.
1) You opened the thread talking about a perfect refresh multiple, 120Hz.
2) For good ht experience 60Hz really is *not* the only refresh rate that should matter, as movies and all the best TV shows are shot at 24fps.
Sport is the only stuff really shot at 30fps.
3) Some judder at 60Hz is normal. Judder at 48Hz with 24fps material makes no sense.
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#80
midgetspy Wrote:Wow guys, READ THE THREAD before you post! Half of you are talking about completely unrelated problems. This thread is NOT about:

- dropped frames
- high CPU usage
- audio/video being out of sync

This thread is about SLIGHT jerks in video playback only visible in slow panning shots.
Way to be irritated.

I posted my observations about jittery video and the fix I found for it because they may help someone who has a similar problem (and will invariably land on this post looking for a solution). The dropped frames and high CPU usage caused slight jerks in video for me. Perhaps you should have renamed your thread to something more specific.

Tom
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#81
midgetspy Wrote:Well you have to know that some judder at 60Hz is unavoidable. The only time perfectly smooth playback is possible is when the refresh rate is a multiple of the fps - if it isn't it can't possible have no judder because there will be a different number of refreshes for each frame.

Well that's where the 120hz TV is supposed to step in. I'm not trying to get around the math or anything. All I'm asking for is the standard 2:3 timing. There's simply no other alternative for tv based software.
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#82
ashlar Wrote:1) You opened the thread talking about a perfect refresh multiple, 120Hz.
2) For good ht experience 60Hz really is *not* the only refresh rate that should matter, as movies and all the best TV shows are shot at 24fps.
Sport is the only stuff really shot at 30fps.
3) Some judder at 60Hz is normal. Judder at 48Hz with 24fps material makes no sense.


1) 120hz tvs work by detecting a 24fps signal over a 60hz refresh.
2) Even if film is 24fps, all non 120hz tvs only work at 60hz refresh. I don't see how that can be made any clearer.
3) 2:3 judder is not the issue here.

Yes, it SHOULD play perfectly at double the refresh rate. No argument there. But that's irrelevant for *TVs*.
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#83
I'm almost positive that it's the same underlying issue at whatever refresh rate, so there's no need for argument. I just entirely disagree that the focus here should be direct multiples. That's a concern of a small minority, and I don't want to see the issue written off as fixed when it's not.
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#84
Quote:all non 120hz tvs only work at 60hz refresh.

That's a bold and incorrect statement, my Plasma TV works at 100hz as it doubles the 50hz standard TV broadcast frequency here in the UK. There is a world outside of the US, fortunately.
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#85
Andydigital Wrote:That's a bold and incorrect statement, my Plasma TV works at 100hz as it doubles the 50hz standard TV broadcast frequency here in the UK. There is a world outside of the US, fortunately.

Internally, yes. But can you set the refresh rate of your htpc to 100hz and have the tv accept it?

If you can, your tv is then in a minority of a minority. I've never personally heard of a 120/100hz tv that can do so.
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#86
worth keeping in mind here, I assume some of the discussions circle around outputting 50, 60, or even higher FPS of video ?

Well, the Intel GMA X3100 can't handle much more than 25fps on Linux @1080p WITH Vsync enabled.
Hopefully GMA X4500 can handle 30 atleast, but not much chance of higher I Guesstimate (as I have no G45 hardware)
Always read the XBMC online-manual, FAQ and search the forum before posting.
Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules.
For troubleshooting and bug reporting please make sure you read this first.


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#87
Nah, the discussion is centered around typical frame rate video (24,25,30) not playing back properly at typical refresh rates (50-60). It can't be a hardware limitation as the problem exists even at 480p.
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#88
Andydigital Wrote:That's a bold and incorrect statement, my Plasma TV works at 100hz as it doubles the 50hz standard TV broadcast frequency here in the UK. There is a world outside of the US, fortunately.

Btw, the anti-American jab is absolutely unnecessary and far from constructive. I'm well aware PAL territories use different standards, but the core issue of jittery playback remains unchanged in either case.
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#89
What refresh rate should force to check if jittering is change or not on 24p capable displays? 24, 48, or 96hz?
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#90
olympia Wrote:What refresh rate should force to check if jittering is change or not on 24p capable displays? 24, 48, or 96hz?
At 24Hz I have no problems. My display is uncapable of displaying 96Hz. At 48Hz I have the strange judder effect.
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