IPB

Welcome Guest ( Log In | Register )

Tweaking the DVI/HDMI monitor for smoother video playback., Rant about jerky video playback.
psycho
post Apr 12 2012, 19:27
Post #1





Group: Members
Posts: 241
Joined: 14-October 05
Member No.: 25099



Hello felow IT enthusiasts...

Something's been bothering me for quite some time now and I want to share it and I also hope someone might have some suggestions I haven't heard of before that could help me...

OK, as you might know, the video on a PC plays smoother if the refresh rate is set to a multiple of the video framerate. Say you have a video at 24 fps, it will playback smoothest at 72 Hz, 120 Hz. If you have a video at 25 fps it will playback smoothest at 75 Hz, 100 Hz. And if you have a video at 30 fps it will playback best at 60 Hz, 120 Hz.

I know all that and I live in a PAL area so most of my videos are at 25 fps and 24 fps. That means it is best for me if I set my Display Properties to either 75 or 72 Hz. MPC-HC player can switch these modes for me - you can define which fps go with which Hz. That's cool and I use that option.


Now we come to my problem. All of the above works if I connect my monitor via D-sub (VGA). It doesn't work with DVI and I haven't tried HDMI yet, as my manual says it's only for connecting to standalone players and not for computers (it explicitly says "HDMI not for connecting to a computer")... And I don't have the expensive HDMI cable anyway. So with DVI, my refreshrate is always 60 Hz on my monitor, no matter what I set on the PC. So the jerky video playback is always present as I almost never have 30 FPS video and for 25 and 24 FPS 60 Hz just isn't OK.

I can't help but wonder why on earth does DVI use the archaic mode of refreshing the screen?? As far as I know, LCDs don't refresh the screen as the CRTs do and DVI is meant for LCDs. So the logic suggests that there should be a mode of operation for LCDs to operate at "whatever-the-input-Hz" so to speak. I mean, it would rock to have such a mode of operation for DVI that it would actually send only changes of current display at any rate it happens... say with 24 FPS video, the DVI would refresh 24 times per second and that's it... Is there something like that? Can one achieve something similar with a PC and LCD monitor? Maybe HDMI (I have no experience with HDMI whatsoever so far)?


Well, that's it... I wish you all a smooth video playback and I hope someone can help me with some tricks. smile.gif


--------------------
lame -V 0
Go to the top of the page
+Quote Post
 
Start new topic
Replies
onkl
post Apr 13 2012, 19:44
Post #2





Group: Members
Posts: 125
Joined: 27-February 09
From: Germany
Member No.: 67444



If the lines aren't straight, that doesn't necessarily mean the video stutters. The important thing is, that both lines stay parallel at each other. If they start to drive apart, snchronization will kick in and that's what's causing the judder. EVR Sync tries to spread this delay to every single frame, thus making the lines spiky but keeping them together. You basically trade one noticable judder for a lot of tiny ones. You may call it jitter, but I doubt that's what you're seeing.
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 26th December 2014 - 01:57