Video Playback Issue

Overslop

Overslop

Overslop

Soldato
Joined
22 Oct 2005
Posts
4,013
Location
Thailand
Bought a Hazro HZW27A recently and mostly I'm very pleased with it. However, there is one particular issue that is bugging me a great deal. I'm not totally sure if the monitor is at fault, but I certainly never noticed this before switching screeens.

When watching quite a number of MKV video files, I get horizontal lines across the screen on some dark backgrounds. As far as I can tell, other video containers are not effected but I haven't tested enough to say conclusively. Additionally, I noticed something similar in the game Zombie Driver though it may be unrelated.

Please see the image below to see what I'm talking about:

6dd8d4ce.png


In attempting to fix this issue, I have tried various media players. VLC Media Player uses self-contained codecs so should not have replicated the fault if it was that kind of problem. Unfortunately it suffers just as badly as Media Player Classic. Oddly, Windows Media Player seems to fare the best.

I've uninstalled and reinstalled the latest K-Lite Codec Packs (both 32 bit and 64 bit versions). This hasn't helped either. I've tweaked countless settings in the media players as well as in the nVidia Control Panel but still no joy. Updating the nVidia drivers didn't change anything.

I'm posting this topic in several forums here in the hope that someone can lead me to a solution. Please don't be offended that I am posting in more than one place. The reason I'm doing this is that I'm not certain what is causing this and want as many people who can help me to read this as possible.
 
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Nope no lines here either. Also a google of "Hazro HZW27A" shows only this page and its not something ive heard of - have you got a link?

Are you seeing the problem on the image you have posted. Maybe you can edit it and circle the problem areas? Maybe the problem is in your monitor? Have you tried swapping the cable to it?
 
I can't see how you can't see the lines! They're clearly visible in the image. I guess your contrast settings are obscuring them.
 
There are definitely lines there as has been confirmed by several users across the forums. Whether or not people can see them varies however. The fact that some people can see it means it's not a monitor/cable issue.

Most likely culprit is poor quality MKV files being upscaled to 1440P.
 
I can see the lines. I would have guessed that it is a monitor / monitor settings issue...?

I am using a Dell E228WFP by the way.

Does the issue stop if you view the videos at their full resolution, rather than full screening it?
 
It could have been noise in the source material or just a low bitrate encode. I dont think their are any other forces at work causing it. Their not really visable enough to annoy. I think youd need your blacks setup to appear nearer to grey to see them (low contrast?)
 
Ok - I've done some investigation using the gimp. Increasing the brightness a step at a time, you DO hit a spot where lines become visable. I used a threshold filter to bring it out. Looks like compression artifacts are present in the source file.



Uploaded with ImageShack.us
 
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The lines are dithering artefacts caused by the video compression.

You've just bought a monitor that can display things properly, so now you see them (it's definitely not a 'fault' in the monitor). More like buying high end speakers and being able to hear the limitations of crappy mp3 files.

You could try using MPC-HC with a 16-225 -> 0-255 pixel shader applied to make it less visible.
 
Yup a few releases of late have had these, some dodgy compression settings if you ask me. Seem to of disappeared on newer encodes.

Everyone else, if you can't see those lines you need to calibrate your monitor!
 
How should I go about calibrating my monitor? For me, the lines seemed to appear when the brightness was turned up to a level that was obviously too high. Contrast adjustments didn't seem to make them visible. Just because there ARE compression artifacts present doesn't mean that a setting which makes them visible is correct.

EDIT - Should this thread be moved to the AV section?
 
masterluke said:
How should I go about calibrating my monitor? For me, the lines seemed to appear when the brightness was turned up to a level that was obviously too high. Contrast adjustments didn't seem to make them visible. Just because there ARE compression artifacts present doesn't mean that a setting which makes them visible is correct.

EDIT - Should this thread be moved to the AV section?
Click to expand...

Use this
http://www.avsforum.com/avs-vb/showthread.php?t=948496

Use the black gradient and white gradient patterns to set your brightness & contrast. Brightness should be set where 16 upwards is flashing, but not below. Contrast should be set so 235 (iirc) is flashing but not higher. Beyond brightness/contrast colour & grayscale calibration you really need some filters or a unit with colour only modes which most monitors will not do.

Basically, monitors can do RGB from 0-255, but films/tv are mastered in a range of 16-235. Because these don't match up, you will frequently get black/white crush if your settings are out. Note however that doing this will alter how 0-255 images look so if your a web designer with an incredibly good screen you will probably want to expand your video players range to 0-255 and calibrate from that.
 
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