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Discussion Starter · #1 ·
So after a week of messing with the Sony XBR-65X850A, I ended up returning it because I could not eliminate the extreme lag when viewing material at 24p. I am looking to buy a new set, but I need help understanding why this was happening.


Most of my viewing material comes from my Alienware gaming PC..brand new with two NVIDIA GTX-770 graphics cards connected to the TV through HDMI.


When I'd output anything at 1080p, 60hz it worked perfectly. However when I wanted to watch 3D material, NVIDIA forced me to change the refresh rate of the card to 24p (Any idea why this is? I thought HDMI 1.4 supported higher refresh rates for 3d?).


This would cause severe lag between the picture and everything else (Audio, mouse input, etc). The delay was at the very least .30 seconds. When I would output a non-3D 24p signal from the PC to the TV the same lag would occur, so it was NOT my PC just having trouble handling the processing load of 3D.


I eventually discovered that turning on the TV's Gaming picture setting *almost* eliminated the lag. It was still there to some extent, but much less extreme. I then realized that turning off MotionFlow in the other modes also reduced the lag.


Sounds like an easy fix right? Turn off MotionFlow and fix the problem? Wrong. When I turned off MotionFlow, 3D was unwatchable. The 3D effect was greatly diminished, and the flickering of the active glasses became extremely noticeable and intolerable. Turning MotionFlow back on yielded perfect 3D...and also the .30 second lag.


I tested this going through my AV receiver and also going directly into the TV's input. Same issue.


Why did this happen, and will it happen on all the other 4K displays available?



Thanks!
 

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My 55W905a I can't  run 1080p 3D @ 60fps from any source. I have to use 24fps @ 1080p.. but if I lower the resolution to 720p I can play games at 60fps, that's the trade off unfortunately. I've spent quite a lot of time reading up on this and testing and it seems it's the HDMI 1.3 standard that is the limiting factor, it's not supporting the bandwidth that two full images (left and right eye) 1080p*2 @ 60fps is requiring. Going full 60fps at 1080p requires the HDMI 1.4 or 2.0 standard.

 

And no matter what TV or monitor you get. 24hz is going to feel sluggish.

 

Also know that Motion Flow. Wait's for about 5 frames to be received so it can create/invent extra frames in-between to make the video motion smooth, it requires a couple of frames to be able to make intelligent decisions of how to crate in-between frames with correct motion. That introduces quite a bit of lag and there is no way to get around this but turning these kind of features off, that's for all TVs and brands..

 

I've measured my TV's lag when Motion Flow is turned on with my Leo Bodnar lag tester at 60hz refresh rate to about 92ms IIRC that's 92/16,67 =  5,5 frames of lag.
 

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Discussion Starter · #4 ·
I think you guys just skimmed over my first post. You seem to have missed the part where I said that it introduced a .30 second (300 millisecond) delay...not a 92 millisecond one. 92 milliseconds is closer to what I would get when I disabled MotionFlow. I could live with that one, however, as I posted before, turning off MotionFlow made the 3D effect freak out.


Re-read my post.
 

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Discussion Starter · #5 ·
Benes, why did you quote lines from previous posts that do not answer my question?


I don't know how much clearer I can make this.


The lag almost goes when disabling MotionFlow. I am asking why this is.


I know there is lag at 24p. I don't need a snotty little post filled with quotes to tell me that.


My issue was that the lag, with MotionFlow, was far beyond the normal lag of 24p. When turning off MotionFlow, 3D effect was reduced.
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by benes  /t/1520154/returned-sony-xbr-65x850a-due-to-extreme-lag-at-24p-why#post_24431944


Ok have fun trying to figure it out then.


Pro-tip: best not to childishly attack people who are trying to help you.

How did you try to help? I don't consider a post filled with someone else's quotes from just a few posts before to be very helpful. It is insinuating that I did not read/understand the replies the first time they were posted. You added nothing new or helpful to the discussion. I find that childish and insulting.
 

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First lets see how much things lag..

 

1 frame in milliseconds at different frame rates:

1sec / 60fps = 16.67 ms

1sec / 24fps = 41.67 ms

 

Inherent lag of TV in (game mode):

KDL-55W900A = 19 ms

XBR-65X850A = 40 ms (surce: http://www.displaylag.com/display-database/ )

 

 

Motion Flow adds roughly 5 frames of delay:

60fps: 5 * 16.67 ms = 83.35 ms 

24ps: 5 *  41.67 ms = 208.35 ms

 

 

Motion Flow added to Inherent display lag at :

KDL-55W900A @ 60fps: 19 ms +  83.35 ms = 102.35 ms

KDL-55W900A @ 24fps: 19 ms +  208.35 ms = 227,35 ms

 

XBR-65X850A @ 60fps: 40 ms +  83.35 ms = 123.35 ms

XBR-65X850A @ 24fps: 40 ms +  208.35 ms = 248.35 ms

 

These are not exact numbers just keep that in mind.

 

 

Secondly...

 

Your TV should be able to handle 4k resolution and is HDMI 2.0 compatible with a firmware upgrade. I guess it could potentially do 3D in 1080p @ 60fps then. Maybe you didn't have the correct firmware for it to work?
 
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Discussion Starter · #8 ·

Quote:
Originally Posted by JoelArt  /t/1520154/returned-sony-xbr-65x850a-due-to-extreme-lag-at-24p-why#post_24433768

First lets see how much things lag..


1 frame in milliseconds at different frame rates:

1sec / 60fps = 16.67 ms

1sec / 24fps = 41.67 ms


Inherent lag of TV in (game mode):

KDL-55W900A = 19 ms

XBR-65X850A = 40 ms (surce: http://www.displaylag.com/display-database/ )



Motion Flow adds roughly 5 frames of delay:

60fps: 5 * 16.67 ms = 83.35 ms 

24ps: 5 *  41.67 ms = 208.35 ms



Motion Flow added to Inherent display lag at :

KDL-55W900A @ 60fps: 19 ms +  83.35 ms = 102.35 ms

KDL-55W900A @ 24fps: 19 ms +  208.35 ms = 227,35 ms


XBR-65X850A @ 60fps: 40 ms +  83.35 ms = 123.35 ms

XBR-65X850A @ 24fps: 40 ms +  208.35 ms = 248.35 ms

These are not exact numbers just keep that in mind.


Secondly...


Your TV should be able to handle 4k resolution and is HDMI 2.0 compatible with a firmware upgrade. I guess it could potentially do 3D in 1080p @ 60fps then. Maybe you didn't have the correct firmware for it to work?

Thanks for the numbers...makes sense.


Does anyone know why 3D is messed up with MotionFlow disabled? If I could have just disabled MotionFlow for the 3D, everything would have been fine.

Quote:
Originally Posted by benes  /t/1520154/returned-sony-xbr-65x850a-due-to-extreme-lag-at-24p-why#post_24431959


Reading is obviously not your strong suit.(I don't think writing is either tbh) Here is the title of this thread:


Returned Sony XBR-65X850A due to extreme lag at 24p...why?

Right...because thread titles are the only place where relevant information is contained. Completely disregard the actual message content. There's just no way there could be other questions in there, right? Silly me.
Quote:
Originally Posted by benes  /t/1520154/returned-sony-xbr-65x850a-due-to-extreme-lag-at-24p-why#post_24431959


Do you seriously expect someone to help you with this kind of attitude?

Why, yes. Most of the other posters in this thread have been quite helpful. Only one question remains unanswered.
 

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Quote:
Originally Posted by (Evan)  /t/1520154/returned-sony-xbr-65x850a-due-to-extreme-lag-at-24p-why#post_24433919



Thanks for the numbers...makes sense.


Does anyone know why 3D is messed up with MotionFlow disabled? If I could have just disabled MotionFlow for the 3D, everything would have been fine.

 
 

I'm not sure I understand you correctly. But "active" 3D glasses that have shutters do flicker at lower to normal framerates. Enabling Motion Flow increases the framerate quite considerably by making up and adding extra frames in-between the original ones. Say for 60fps, it most likely inserts another 4 frames per frame, resulting in a new fps of 240 frames per second. And for 24fps you may end up getting 96fps or 120fps depending of how many interpolated frames the TV inserts. This makes the flickering go away and make the motion of the video very smooth. But at the cost of serious lag.

 

I would strongly advice against using any form of motion interpolation setting on a TV or projector when gaming. Watching movies is not such a big deal if you have the option of delaying the audio. All tough the mouse will be slow as h*ll.

 

As I mentioned, your TV should be capable of handling 60fps 3D at full resolution with the latest firmware, but don't take my word for it ;). If it can't as is the case with my TV. you have the option of lowering the graphic cards output resolution to 720p instead. Then you can play games at 60fps with low lag.

 

 

In essences: Motion Flow creates non existent frames, makes everything smooth and flicker free but adds quite a bit of lag. Turn it off and things are responsive but may flicker.
 
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