Leo's exciting hand held LAG TEST device - out now !

[Fudoh]

The problem is that the processing chain is so complicated.

LEO's > down converter > convert to analogue > scan convert to 240p

and then you feed your processor.

My lag test results with 240p sources are:

- XRGB-3 in B1 (linedoubling mode): 2ms
- XRGB-3 in B0 (scaling mode): 21,4ms
- XRGB-Mini: 24,5ms
- Vigatec FX2: 32,1ms

[NWrain]

Even after that processing chain B0 is 2ms. That is really amazing.

What output resolution and options did you use for the XRGB-mini? B0 mode for the Mini would be really nice.

[Fudoh]

The whole pre-processing takes it time of course, so it's calculated out of the end-results.

Mini was 240p input, 720p with scanlines output, standard mode.

[marqs]

for those interested, there is an online database of HDTV/Monitor (all tested with Leo Tester) : http://www.displaylag.com/display-database

I'm surprised about Plasma input lag ! I heard that PANASONIC ST50 *WAS/IS* 16 ms but it is not .

We should to do something similar for our scalers ...

It seems they are (incorrectly) using the bottom bar readings in the results (see http://www.displaylag.com/the-lag-teste ... -standard/), which would seemingly add ~13ms to the numbers.

If there's more people interested testing with analog sources, I can share the schematics and code for my vga lag tester.

[Fudoh]

which would seemingly add ~13ms to the numbers.

this happens on none of my displays. The difference between top and bottom are 1 ms max on my PC LCDs, my Sony TV and all other displays I've tried myself.

[akumajo]

vga lag tester you said ? tell us more please

[marqs]

which would seemingly add ~13ms to the numbers.

this happens on none of my displays. The difference between top and bottom are 1 ms max on my PC LCDs, my Sony TV and all other displays I've tried myself.

Yes, my comment is only true for displays with CRT-style refresh logic. Funny that all the flat panels I've tested (just a couple though) seem to belong to this category.

vga lag tester you said ? tell us more please

It's a simple DIY-system with a microcontroller, lcd-display and photoresistor . You use PC to generate the input signals via VGA, and tap one color channel (and ground) from the vga cable to the microcontroller's A/D converter. The controller monitors the voltage on the line, and once it goes over a threshold (test sequence is a simple black->white transition video), a timer is started. Assuming that video playback is synced to vblank, this happens at the beginning of the first scanline. The photoresistor is positioned at the top-left corner of the display, and when the brightness threshold is exceeded, the timer is stopped, and the result is shown on the lag tester display.

I'll write a proper article soon with all needed info to build one. For now, I added a few photos I took when I was measuring XRGB mini with Eizo FS2333 here.

[BuckoA51]

My lag test results with 240p sources are:

- XRGB-3 in B0: 2ms
- XRGB-3 in B1: 21,4ms

You got those the wrong way round right? B1 (linedoubling) is almost lag free while B0 is not...?

for those interested, there is an online database of HDTV/Monitor (all tested with Leo Tester) : http://www.displaylag.com/display-database

Ha bizarre, I was planning to do that myself, even been talking to a database guy about it, oh well saves me a job I suppose

[Fudoh]

You got those the wrong way round right? B1 (linedoubling) is almost lag free while B0 is not...?

of course. B1 is the fast one

[BuckoA51]

I just got hold of mine today, tested my supposedly super low input lag Sony TV, (KDL-40Z4500) Reviews place the lag at 0 to 10 ms....

Game mode on 30ms
Game mod off 60ms







This sure is going to be an interesting afternoon...

[Fudoh]

What I find most surprising is that so many readings are so far off compared to classic measurement methods.

When I used the lag tester on my displays all my readings were within 1-2ms of what I checked with the classic CRT/LCD photo testings before.

If you check HDTVtest's reviews, for example this one: http://www.hdtvtest.co.uk/news/panasoni ... 062961.htm

23ms in camera-test mode and 42ms with Leo's device. It's possibly down to the interpretation of what the camera pics show you - - still wondering why my readings were basically identical.

[BuckoA51]

Yeah I was a little shocked, I mean not going to lose sleep over it. Discussing my shock at having more input lag, my GF just said "that must mean you're an even better gamer than you thought!"

Also, on some displays I'm seeing big discrepancies between the bars at the top, middle and bottom, yet on other displays, I'm not, very odd.

Also from what measurements I've done so far, I can report that the DVDO Edge seems to be reporting input lag honestly (in its audio delay setting) and our older Onkyo AV system (that does not include image processing) does not add any lag....

I'll continue testing!

[BuckoA51]

Ok, this is a wild theory and I could be way off the mark here but...

I noticed that the lag tester outputs at exactly 60hz, if a set is converting this to 59.94 internally, could that skew the results? Could a tiny variation in frame rate like that cause the discrepancies you sometimes get between the three strips on the screen too?

[Fudoh]

extremely unlikely, also 60Hz straight is the proper VESA timing, while 59.94Hz is the SMTPE broadcast timing.

Also framerate conversions like this are frame-based, meaning that the display would just insert a frame every other second or so to keep track.

We've been wondering about the differences between the three measurement areas before. I don't get that here, not on my Sony TV and not on my LCDs at my workstation. Has to do something with how some panels internally work.

[BuckoA51]

Yeah I don't really see it (give or take a millisecond or two) on my Sony TV, but on my dell monitor there was more than 10ms difference between the top line and the bottom one.

I also hooked up a HD Fury and tested my Extron RGB interface, I could not detect any change in input lag with the Extron in the chain.

[marqs]

Yeah I don't really see it (give or take a millisecond or two) on my Sony TV, but on my dell monitor there was more than 10ms difference between the top line and the bottom one.

I also hooked up a HD Fury and tested my Extron RGB interface, I could not detect any change in input lag with the Extron in the chain.

Sony KDL-40Z4500 seems to be a 200Hz TV, which means it internally refreshes one input frame several times like plasmas. Assuming it doesn't process incomplete frames, the maximum diff between top and bottom would be 5ms. Disabling motion interpolation on a LCD like that could theoretically set the internal refresh to 60Hz to match the input signal, but apparently not with the Sony if the difference stays same in game mode (where any interpolation should be disabled).

[marqs]

extremely unlikely, also 60Hz straight is the proper VESA timing, while 59.94Hz is the SMTPE broadcast timing.

Also framerate conversions like this are frame-based, meaning that the display would just insert a frame every other second or so to keep track.

We've been wondering about the differences between the three measurement areas before. I don't get that here, not on my Sony TV and not on my LCDs at my workstation. Has to do something with how some panels internally work.

I sent a mail to DisplayLag and asked them to include readings from the top-bar in the database in addition to currently used bottom-bar values, which are always >16ms even on a perfect display. That would reveal the refresh logic in each display and provide means to calculate worst-case and average latencies.

[BuckoA51]

Sony KDL-40Z4500 seems to be a 200Hz TV, which means it internally refreshes one input frame several times like plasmas. Assuming it doesn't process incomplete frames, the maximum diff between top and bottom would be 5ms. Disabling motion interpolation on a LCD like that could theoretically set the internal refresh to 60Hz to match the input signal, but apparently not with the Sony if the difference stays same in game mode (where any interpolation should be disabled).

Input lag is higher when game mode is off (60ms vs 30ms) but still disappointing. We've got a Sony KDL-32W4000 through in our conservatory (sun room). We got this one again on the premise that it was low input lag as it gets used for Wii and rhythm games etc in summer and at Christmas. That set has an excellent 11 to 12ms of input lag. According to HDTV Test the KDL-40Z4500 should match that as long as game/text mode is on, but clearly it does not. Bit of a shame as I went out of my way to get both of the sets at the time. still, 30ms is considered acceptable these days

[marqs]

Sony KDL-40Z4500 seems to be a 200Hz TV, which means it internally refreshes one input frame several times like plasmas. Assuming it doesn't process incomplete frames, the maximum diff between top and bottom would be 5ms. Disabling motion interpolation on a LCD like that could theoretically set the internal refresh to 60Hz to match the input signal, but apparently not with the Sony if the difference stays same in game mode (where any interpolation should be disabled).

Input lag is higher when game mode is off (60ms vs 30ms) but still disappointing. We've got a Sony KDL-32W4000 through in our conservatory (sun room). We got this one again on the premise that it was low input lag as it gets used for Wii and rhythm games etc in summer and at Christmas. That set has an excellent 11 to 12ms of input lag. According to HDTV Test the KDL-40Z4500 should match that as long as game/text mode is on, but clearly it does not. Bit of a shame as I went out of my way to get both of the sets at the time. still, 30ms is considered acceptable these days

Have you measured KDL-32W4000 with Leo's tester? I bet you'll also get ~30ms reading from the bottom bar. That seems to be a normal 60Hz LCD, so you'll probably get 14-16ms less from the top-bar, which represents the real latency in that case.

[BuckoA51]

I am beginning to think my lag tester is faulty. I tested my friends HDTV today and got a reading of just 2.5ms! When I got home I re-tested both my Sony panels. One has 30ms as before, but the other one now has between 1.5 and 0ms! Something has to be screwy here, right?

[BuckoA51]

Alright so is my lag tester faulty, or are non-motionflow Sony TV's insanely fast? On the Sony KDL-32W4000 I'm now getting 0ms on the top and bottom bars and between 0 and 5ms on the middle one. The lag tester will count up slowly from 1 to 5 then jump to zero and stay there, weird...

Here's a result from a KDL-37EX403:-



That seems fast, really fast... I re-tested a few displays and all the slower ones were reading the same, but the Sony KDL-32W4000 seems to have got faster. Really I don't see how that could be, how accurate do we think this thing actually is?

[Fudoh]

from a technical perspective there's not much room for error.

What about testing the very same display with the good ol' series of digicam pictures ? Any other display nearby ?

[marqs]

Alright so is my lag tester faulty, or are non-motionflow Sony TV's insanely fast? On the Sony KDL-32W4000 I'm now getting 0ms on the top and bottom bars and between 0 and 5ms on the middle one. The lag tester will count up slowly from 1 to 5 then jump to zero and stay there, weird...

Here's a result from a KDL-37EX403:-

That seems fast, really fast... I re-tested a few displays and all the slower ones were reading the same, but the Sony KDL-32W4000 seems to have got faster. Really I don't see how that could be, how accurate do we think this thing actually is?

0-5ms from the middle bar should be impossible, since it takes over 5ms for the signal to get to that point. Could it be possible that the backlight bleeding triggers the device ahead of time? Or could there be some afterglow from the previous frames where the bar was shown?

[BuckoA51]

0-5ms from the middle bar should be impossible, since it takes over 5ms for the signal to get to that point. Could it be possible that the backlight bleeding triggers the device ahead of time? Or could there be some afterglow from the previous frames where the bar was shown?

Possibly, how would you compensate for this? Perhaps the room is too dark? It's pretty pitch black in the room where the KDL-32W4000 is after sun-down.

[marqs]

0-5ms from the middle bar should be impossible, since it takes over 5ms for the signal to get to that point. Could it be possible that the backlight bleeding triggers the device ahead of time? Or could there be some afterglow from the previous frames where the bar was shown?

Possibly, how would you compensate for this? Perhaps the room is too dark? It's pretty pitch black in the room where the KDL-32W4000 is after sun-down.

Can you turn the TV backlight to minimum, contrast to max and try again? Will it show any reading if you set the tester to a spot where the bars aren't drawn?

[Fudoh]

0-5ms from the middle bar should be impossible, since it takes over 5ms for the signal to get to that point.

are we certain that the tester starts counting after emitting the first line of the frame and not only after finishing a full frame ?

[marqs]

0-5ms from the middle bar should be impossible, since it takes over 5ms for the signal to get to that point.

are we certain that the tester starts counting after emitting the first line of the frame and not only after finishing a full frame ?

Nwrain's resuls on the previous page vs my tests with FS2333 would indicate that. If the counting was started after finishing the frame, the fastest TVs would show negative lag - the fastest displays in displaylag.com are rated ~18ms instead (taken from bottom bar). I probably should buy Leo's tester to study this more closely.

[Four Wude]

Hello everyone, I run Display Lag and I wanted to gather your feedback. As of right now I've personally graded 148 displays and continue to grade as many as I can. I received an e-mail from marqs and I figured I'd chime into this community.

First, I'd like to note something about that Sony you guys are having issues with. Here in the US, my friend has a Sony TV from the same/similar model line as the one that's causing issues for you guys, and it exhibited the same behavior that you're experiencing with 0ms on the middle bar. It was the only HDTV I have graded (even among Sony's 2012 and 2013 models) that caused such an issue. I'm not sure what is causing it, therefore I chose not to report the display in my database as it seemed sketchy. So don't be too quick to think your tester is broken, for some reason that specific Sony model line acts weird with the tester.

I'd also like to gather opinions on the differences between the top, middle, and bottom bars. As some of you know, all ratings in my database are calculated from the bottom bar. I decided to adopt the same standard that AVForums use as it was the first authority website to use the Lag Tester in their reviews; they use the bottom bar. I was also recommended by John Beeson (Leo Bodnar's associate) to use the highest ratings I can get as a reference (which are typically found on the bottom bar).

There has been some discussion about using the top bar instead of the bottom, based on what marqs emailed me. Unfortunately, I only started recording all 3 ratings on the last 55 displays inserted into my database (which leaves a good 93 displays with only bottom bar results).

Please advise, and thanks for the support! I don't intend to mislead anyone and want everyone to be on the same page. If you have any questions, feel free to ask.

- Adeel

[NWrain]

Where is the third bar in that photograph.

[Fudoh]

I'd also like to gather opinions on the differences between the top, middle, and bottom bars

I would be really interested in understanding the technical background, why some displays would show differences in the readings when using different bars, while other displays will give the same results no matter which bar is used.

I can understand a certain difference (in the single ms range). That's just the time the display needs to draw the whole screen, so you get subtle brightness differences which show in the readings, but how can a display show a whole frame of difference between the top and bottom bar ? Imagine the input signal not being a static screen like it is now, but a horizontally scrolling game. A time gap of up to 16ms between the top and the bottom of the screen would cause serious tearing - to a degree where the display would not be useable anymore for any kind of gaming...