LG CX OLED vs good pc monitor input lag?

[jorimt]

Could you do some basic input lag tests with BFI off and BFI on at 120hz? I'd like to know how much it would add at 120hz.

If I ever feel the urge (and get the time), I'll let you know, and would post them here, but as I noted in an earlier post, it's not something I'm actively planning on doing.

But since non-BFI (1080p) input lag at 60Hz is ~14ms, and at 120Hz it is ~7ms, my guess is the BFI input lag at 120Hz would be a relatively proportionate drop (about half) with the current behavior of BFI on this TV.

-60hz bfi mode increases input lag compared to 60hz non bfi mode
-60hz bfi reduces peak brightness as low as 60 nits, other higher frequencies up to 100 - 120hz have arround 116nits

Yes.

-other freqs like 80hz are not available for bfi, so only 60 100 120 are

Yes, though that was just out-of-box; I haven't tested whether you can make a custom 80Hz res, but it's theoretically possible.

it seems bfi on oled are still more flicker aggresive than crt at same frequency

At 60Hz yes, at 100Hz and 120Hz, "High" was definitely less flickery than CRT to my eye.

[Adi-C]

First of all, hi! I've been a long time lurker here, and this thread finally made me join officially : )
I'm very interested in lower than 120hz strobing, so 100hz (on an oled no less) would be great, but I'm not sure it works...?

"Game" picture mode, "OLED Motion Pro" set to "High," "OLED Light" set to "100," "Color Temperature" set to "Warm2"

60Hz:
- ~10% window (white) = ~60 nits
- Full field (white) = ~24 nits

100Hz:
- ~10% window (white) = ~116 nits
- Full field (white) = ~46 nits

120Hz:
- ~10% window (white) = ~116 nits
- Full field (white) = ~46 nits

So, thanks for doing these tests! It's sad pretty much nobody tests bfi in tvs properly. 100hz mode with bfi would be super welcome, as it's way easier to achieve solid 100fps as opposed to 120hz. It's mainly cpu/ram issue in a lot of games, so it's not as easy as some people think "wait for a 3090ti"- well, if you're gpu limited, sure. Not so if you're playing something cpu/whatever limited... A new gpu isn't going to do much then.

Working 100hz bfi on an oled would be great news, sadly- it doesn't look like it does- no difference between 100 and 120hz in terms of brightness, with exactly same values? This can't be right?

The values for brightness at 120hz are about 2x higher than at 60hz, which is what you'd expect, here's rtings bfi graph for cx55
https://i.rtings.com/images/reviews/tv/ ... -large.jpg
The strobes are the same width/length @120 and @60hz, and probably the same amplitude-I think we can ignore the y axis (120hz is at "8", whereas 60 is at "4"), the strobes almost certainly aren't 2x brighter @120 than @60, they are just 2x more frequent, and that's what makes 120hz mode brighter. If the strobes were 2x higher, and 2x more frequent, the image should be 4x brighter (I think?), so it's probably just rtings not caring about the y axis.
Your 120hz to 60hz comparison would suggest the same- 116nits vs 60nits, 46 vs 24nits it shows 2x brighter image @120 than @60. So the amplitude is probably the same.

So... we have 120hz being 2x brighter than 60 with twice the amount of pulses, and this is probably already maximum of what oled could pull off, without any "overvoltage" so then since you would expect 100hz pulses to be the same width/height, so same "singular strobe brightness", so... @100hz bfi we should see less brightness, about 83% of 120hz bfi brightness, about 166% of 60hz bfi brightness.
If it's really the same @100 and 120, then my guess would be 100hz is actually displayed as 120hz, with every fifth frame displayed twice...? That should stutter a bit, and should be visible? That would suck, I really hope 100hz would work properly...

As for custom refresh and bfi, here's a guy saying someone told him he got 80hz bfi, but no confirmation since.
https://hardforum.com/threads/lg-48cx.1 ... 1044638516
And many more say they didn't get any custom refreshes to work at all, except for (I think) 67hz (or 66 or 68, can't find it now) I've seen somewhere. But dunno about bfi @ this refresh.
75 or 85, even 90 with bfi would be awesome, but even 100hz would be very good.

Btw. since rtings included x axis values (time) if you count pixels of the strobe, you can find the actual length of the strobe is about 3.5ms but it takes a bit of time to reach full peak, and then to fall down, so average is more like 3.345ms, making this nearly 5x less persistence (4.98x) than 16.6ms.
https://imgur.com/5XJEpsg
That's nice blur reduction, now if it only worked @ say, 85hz which is achievable easier than 120fps...

[jorimt]

I'm very interested in lower than 120hz strobing, so 100hz (on an oled no less) would be great, but I'm not sure it works...?

It was working about as well as 120Hz in the UFO Test, by eye at least. I don't have an oscilloscope or the like to verify further, so that's all I can say.

So, thanks for doing these tests! It's sad pretty much nobody tests bfi in tvs properly.

I honestly don't think LG prioritized this as a pure "gaming" feature, but merely tacked it on in game mode as it was probably easy to include and would attract a few more people.

The truth is, TV manufactures such as LG consider the mainstream "gamer" crowd those who prioritize higher brightness, higher Hz, HDR, and VRR. I'm sure they consider BFI "niche" in comparison, else they would have probably given it more attention and prioritized lower input lag, more out-of-box strobing settings, more supported Hz, etc.

Heck, theoretically, they could have possibly attempted a rolling strobe if it was important enough to them.

Working 100hz bfi on an oled would be great news, sadly- it doesn't look like it does- no difference between 100 and 120hz in terms of brightness, with exactly same values? This can't be right?

Yeah, that's what the device read.

If it's really the same @100 and 120, then my guess would be 100hz is actually displayed as 120hz, with every fifth frame displayed twice...? That should stutter a bit, and should be visible? That would suck, I really hope 100hz would work properly...

It didn't visibly stutter in the UFO tests at 100Hz "High" BFI.

As for custom refresh and bfi, here's a guy saying someone told him he got 80hz bfi, but no confirmation since.
https://hardforum.com/threads/lg-48cx.1 ... 1044638516
And many more say they didn't get any custom refreshes to work at all, except for (I think) 67hz (or 66 or 68, can't find it now) I've seen somewhere. But dunno about bfi @ this refresh.

Haven't tried creating a custom res for BFI myself, so can't say.

Btw. since rtings included x axis values (time) if you count pixels of the strobe, you can find the actual length of the strobe is about 3.5ms but it takes a bit of time to reach full peak, and then to fall down, so average is more like 3.345ms, making this nearly 5x less persistence (4.98x) than 16.6ms.
https://imgur.com/5XJEpsg
That's nice blur reduction, now if it only worked @ say, 85hz which is achievable easier than 120fps...

Due to the fact that OLED is virtually 0 GtG, the only thing left is MPRT, so even higher MPRT on OLED will probably tend to look lower than the same MPRT on an LCD with BFI.

Sonic Mania on PC @60Hz "High" BFI on this TV, for instance, while flickery/dim by many a gamer's standard, has little to no visible persistence, at least with the max horizontal scrolling speed of this particular game.

[Adi-C]

Thank you for the reply.
Yeah, it's sad how huge companies don't care for very small improvements that would've cost them absolutely nothing to implement. Such are big businesses though I guess : (
I remember that for the longest time, since like 2010-11 sony has had a motionflow impulse 60hz strobing in its tvs, usable in game mode, it was a very short strobe, very dim : ) but it was there. And it nullified blur.
The only thing was- it was just too damn dark!
Samsung has had bfi @60 as well, single strobe, much brighter, basically 100% awesome... but wouldn't allow it in game mode! And non game modes were super laggy back then, even without any interpolation (that's kind of still the case).
Then about 2015 hdr happened, so I thought "well, now sonys going to have bright strobes, finally!". I mean- hdr requires bright leds, right? So finally sony's impulse mode will be usable! ...Well, no. Instead, sony tvs got brighter, sure, but... they've disabled 60hz single strobing completely, and went with 120hz all the way, so you have pwm effectively... So double images when fed 60fps signal or quadruple when 30fps... There's no 60hz single strobe mode on sonys since, except for some 75" models from what I've seen.
So when technology caught up, and allowed that "brightness gap" for bfi to disappear, they... didn't use it at all... The brighter diodes are there! Use them! But- no.
On the other hand samsung learned to allow 60hz single strobe in game mode along the way, but it also took them like 5 years... They had this mode for years in movie mode, and it worked great, but just wouldn't allow it in game mode, and why wouldn't they? It's just stupid : (
But I'm getting offtopic here!

If it's really the same @100 and 120, then my guess would be 100hz is actually displayed as 120hz, with every fifth frame displayed twice...? That should stutter a bit, and should be visible? That would suck, I really hope 100hz would work properly...

It didn't visibly stutter in the UFO tests at 100Hz "High" BFI.

Huh, so maybe it really does somehow work @100hz, that would be a big deal! I wonder though- how would this equal brightness be achieved, even theoretically- 100hz a singular strobe would have to be driven 20% (or so) brighter that 120hz to be the same brightness, but then... why wouldn't they use this brightness increase in 60hz as well? 60 is exactly 1/2 of 120's brightness, no more... Or maybe they just make the strobe a bit longer @100hz? Oh well
Since you didn't notice stutter, I'm going to assume that it somehow works! And this is really nice, since 100hz, while high is still more easily achievable then 120hz. So that's great!

Again, thanks for these tests, I think it's first time anybody on the internet measured bfi's brightness at 60 and 120hz, and 100.
116 nits is bright enough imo, i use a monitor set to like 80 even in daytime, and only go to something like 120nits when editing photos... And full 100% white screen, though quite dim at below 50nits, isn't really needed to be very bright...

[deama]

I currently have my monitor set to 30 brightness and 22 contrast, this has worked fine for me so far.
About a week ago I tried a software implementation of BFI to test things out, and found out that I can easily cancel the lower brightness level by just upping my monitor's brightness/contrast to 60-70, however this is for a 300 nit monitor (at least that's what it said in the specs).
However, keep in mind, this was at 120hz + BFI, so basically 60hz was black, and 60hz was rendered, so I believe this works out to be similiar to an OLED going 60hz with BFI. If the brightness does indeed increase by about 2x, I would have to lower my brightness/contrast settings further down, so, from my perspective, at 120hz + BFI (240hz), I wouldn't even need to go 100% on the OLED as that would still be too bright lol.

The biggest issue for me would be the added input lag, but I'm not entirely sure how much my current monitor has, so I don't really have any comparison per say. For all I know, my current monitor may have more input lag than the CX would have in gamer mode at the same hz (120), it may even have better input lag, who knows.
My monitor is a cheap 120hz 27 inches 1080p that I got about 3-4 years now, TN panel too, I can't find any input lag measurements anywhere for it, but since it's TN, it can't be that high right?

[AddictFPS]

I wonder though- how would this equal brightness be achieved, even theoretically- 100hz a singular strobe would have to be driven 20% (or so) brighter that 120hz to be the same brightness, but then... why wouldn't they use this brightness increase in 60hz as well? 60 is exactly 1/2 of 120's brightness, no more... Or maybe they just make the strobe a bit longer @100hz? Oh well

This is my supossition, assuming that BFI High use the reported "laggy loop":

120Hz [Black-Frame-Black-Frame] at 240Hz granularity
100Hz [Black-Frame-Black-Frame] at 200Hz granularity
60Hz [Black-Black-Black-Frame] at 240Hz granularity

If 100Hz and 120Hz use the same brightness, should result in the same screen brightness, because in both modes, the time oled is on during 1s is the same, 1/2s. However 60Hz is 1/4s. All three using the same max. allowed oled brightness that ABL provide for SDR.

60Hz:
- ~10% window (white) = ~60 nits
- Full field (white) = ~24 nits

100Hz:
- ~10% window (white) = ~116 nits
- Full field (white) = ~46 nits

120Hz:
- ~10% window (white) = ~116 nits
- Full field (white) = ~46 nits

Why ?
[60Hz 60nits] [100/120Hz 116nits], when in teory should be 120nits
[60Hz 24nits] [100/120Hz 46nits], when in teory should be 48nits

Sadly this TV do a small brightness drop between granularity steeps, and this issue force Rtings to not consider it 100% FlickerFree.

https://www.rtings.com/tv/reviews/lg/cx-oled
https://i.rtings.com/images/reviews/tv/ ... -large.jpg

If jorimt say 100Hz ufo is perfectly smooth, is that is true 100Hz. When some day pursuit video arrives, we can see it.

[jorimt]

When some day pursuit video arrives, we can see it.

Update: I did attempt to capture pursuit videos with my Note 9 this weekend, but the 4k and 1080p 60 FPS camera modes were causing artifacts not visible in person (going out of phase with what the TV was showing and causing occasional double image, skipping, etc). 30 FPS mode was fine, but I'm not sure how useful those would be if I took them.

Basically, if you've seen pursuit tests on a 240Hz monitor, the 60Hz, 100Hz, and 120Hz "High" BFI mode on the CX (as the Chief layed out earlier in this thread) have approximately the same MPRT (maybe a little better), but without the strobe crosstalk or overdrive artifacts (no smearing, ghosting, overshoot, undershoot, etc).

So we're still talking 3-4ms MPRT at best. This is plenty to clear up the average side-scroller (again, 60Hz "High" BFI works really well in 60 FPS games like Sonic Mania, Mario Maker, Retro emulated titles, etc), but once the motion gets too fast (say, anything well over 960 px per sec), 3-4ms MPRT can only do so much.

I'd still say it's worth it as a bonus if you already bought the TV for another primary purpose (e.g. non-strobed 4k 120Hz HDR/VRR gaming), but if you're buying the CX solely for its strobing capability, my guess is you'd be disappointed, at least with current functionality (that, and the input lag increase, especially at 60Hz).

It's possible they will continue to improve BFI implementation in further firmware updates, but I wouldn't hold my breath.

[Suprx]

O dont know tou guys measure input lag but i Will send pics that i did today..

How Can o send pics?

I hooked my laptop in my receiver, from passtrought to the 55B7 and 65CX in same time..

The results

B7 got 21 to 30ms

Cx 30 to 40ms

So, i have did the test becouse i fell something more heavy and slow on image moviment on cx.

The results i found made me more relaxed, um not Crazy! I guess...

[AddictFPS]

LG CX owners, have sent feedback to LG to fix BFI sequence with a new firmware ? Anyone has received answer from LG support ?

[AddictFPS]

Rtings first review LG CX 55" not measure input lag with BFI, but in the recent CX 48" review do it, and show 15.3ms with 4K 120Hz BFI High. Sadly not with 60Hz or Medium/Low settings.

https://www.rtings.com/tv/reviews/lg/cx-oled
https://www.rtings.com/monitor/reviews/lg/48-cx-oled

CX 48 is also Smart TV, but they place it in monitor section.

55" review use old firmware, without support for Freesync, but 48" review has last firmware, specs confirm Freesync support. Maybe LG fixed laggy BFI sequence with the Freesync firmware ?

My friend measured the cx oled with bfi enabled at 60hz and the input lag is 29ms. That seems higher then i would expect. This is with motion pro on high(medium is double strobing for some dumb reason).

I'm wondering if they are doing 240hz internally in this sequence (black | black | black | real frame) that would explain the input lag and it's less on medium which seems to be (black | realframe | black | realframe). no idea what they are doing for the low setting but apparently it does not reduce blur at all.

puzzling choice by lg.. why wouldn't they do it like this?

high (real frame | black | black | black)
medium (real frame |real frame | black | black)
low (real frame | real frame | real frame | black)

less input lag and medium and low become useful.

Your friend has installed the update and check again lag ?