Judder

SpellowHouse

SpellowHouse

SpellowHouse

Soldato
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I have a media PC, which is a 12400T, with the intel onboard GPU driving a new Sony TV.

The problem I am getting, I think, is Judder.

It certainly fits the description of Judder and I can eliminate the problem by switching to a refresh rate of 24Hz. The problem seems to be worst at 30Hz, and somewhat better at 60Hz. I believe that 120Hz would be good, except the intel won't go that far!

What I really don't understand is why it's so bad. I mean it really is terrible. Yet, if I watch the same content on a really old Samsung or slightly newer LG, there is no sign of the problem at all.

Checking the settings inside the TV and everything is correct.

I need to sort the problem out quickly, because I have the option to return the TV. I did get money off because of a delivery issue, so I am reluctant to return it, but will unless I can sort this problem out.

I mean, I suppose I could always leave the TV at 24Hz, but that just doesn't seem right.
 
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I think the Sony is going to have to go back.

I compared two 4K TV's, side by side, with two different PC's. Swapping PC's over to ensure it was nothing to do with them. The PC's are identical, but just to make sure! They are both 12400T with same HDD in them that contain a film that I used for comparison. Alita, Battle Angel.

It's a good film because a problem happens within the first few minutes of the film. When the film shows the top of the flying city then pans to the left and down to show the junk falling from the city, this usually manages to cause an issue. Not always. There is some juddering during that panning process.

On the LG, at 30Hz, the problem is almost invisible. You only notice it if you are looking for it. At 60Hz, it's gone.

On the Sony, at 30Hz it's terrible. At 60Hz its a little better. But, distressingly, even at 24Hz, it's still there. I'm not sure whether it qualifies as judder then, perhaps it's jitter. I suppose that it's easier to call it motion problems!!!

Whatever, at the moment, the conclusion is that the Sony is not good at all.
 
hornetstinger said:
Try using a de dedicated video movie box, or whatabout using the TV's own media player?

Maybe PC doesn't do a good job of framerate switching?
Click to expand...

I would think that except the LG has no problem with the PC.

Also, there are definitely times when the problem seems to be the TV. I can't exactly describe it, but the motion correction is not even. Again, a problem that is not evident on the LG.
 
OK. I repeated the tests and I was unable to reproduce the so called jitter at 24Hz. I think I must have had the refresh rate set to the wrong value, and indeed the problem is judder when the refresh rate is anything other than 24Hz.
So, basically, the TV is fine at 24Hz, but nothing else. Now I have to decide whether I think that is acceptable.
 
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stuman said:
You might want to have a play with the motion settings in the telly.

Another spanner could be tricks like auto-low-latency / game mode etc.

Depends when you need to make up your mind by?
Click to expand...

That's it!

The motion settings were Custom. I didn't even notice that until I saw your comment and took a look. Switching them to Auto seems to have solved the problem. None of the tests are showing motion problems now. I just need a nights viewing to make sure.
 
stuman said:
Glad you got it sorted. Thought it was odd - Sony are known for pretty good motion handling.
Click to expand...

I've managed to define the problem even further.

I noticed that the problem was only present in some display modes, even ones where MotionFlow was permanently disabled.

As you switch modes, so it changes the settings of the "MotionFlow" and sometimes it switches in a motion option called "Film Mode". It's a sub-menu of motion smoothing.

The Film Mode is the problem. When it's on, it can introduce judder. When it's off, everything seems fine. I have no idea why it is causing a problem, but it is.

Film Mode is interpolation.

The way to avoid Film Mode is to select one of the display modes that doesn't have it. Unfortunately both the Standard and the Cinema modes do.

However, in both these modes you can just switch it off. It's just something people have to do...
 
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Nutty667 said:
I assume you mean in films?
It's because you're trying to watch content that is 24 frames a second, on a screen refreshing at 30 frames a second. The two don't mix.

The correct way to fix is to have the screen an exact ratio of the frame rate. TV's automatically do this when streaming movies or watching DVD's/Blurays.
You want 24hz or 48hz for example.

Ideally it should switch automatically, but for that you probably need special video player software that sends the required refresh rate down the HDMI cable.
What software are you using to playback content on the media PC ? Stuff like Media Player Classic should do the switching automatically.
Click to expand...

No. In everything.
Some picture modes places MotionFlow in the way, which has several sub-options. One of the sub-options is called FilmMode, which is interpolation. For some strange reason, interpolation causes a problem with absolutely everything.
Even if I match the frame-rate of the source to the material, it still Judders, just is slightly reduced. I have no idea why it is missfiring like this, but the solution has been to switch off FimeMode for all picture modes.

It would be nice to switch the refresh rate of the PC to match. I clueless about that, though. I'm using VLC player. Is that a bad choice? Is there something better?
 
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