Time Sleuth Lag Tester

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Zerp
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Re: Time Sleuth Lag Tester

Post by Zerp »

TrantaLocked_ wrote:Eatnumber1, I think I might be on to something too, with very similar results to your's although my Sharp TV does use PWM and the frequency is probably 120Hz or 240Hz based on reviews of similar TV models (1)(2). In my case the starting value isn't 100% stable like your's, but rather gravitates down at about .01ms / s until hitting a value near 22ms and staying there. I do think it's possible that it's due to refresh rate sync and not PWM in both our cases, with your 120Hz TV naturally having a 8ms range while my 60Hz TV having a 16ms range. I think that it's possible due to what the sync state is when the Time Sleuth pairs with the TV. At time of pairing, if the TS sends the output just after or just before the TV's most recent frame finished drawing (plus base input lag), or somewhere in between, that determines what the remaining time the TS output needs to wait for the current frame to finish drawing for the rest of the session, until power cycle for either TS or the TV. The minimum lag of my Sharp TV is 22ms, so to see a 38ms starting lag value, the first TS output would need to be sent just after ~10ms into the TV's second to last frame drawing before paring, and just before ~10ms for a 22ms starting value.

I've been power cycling the Time Sleuth and the TV in different combinations and have noticed what the starting values tend to be. The range of starting values for 720p is 22ms-38ms, and I believe the starting value is random (as it naturally should be, but certain conditions can lead to a higher likelihood of a particular starting value). In my case, the difference between 720p and 1080p is that for 1080p I see the full cycle play out within 10 seconds, but the other resolutions give me a more stable (but still changing) starting number. Maybe just the TV's PWM being different depending on input resolution. Could chriz2600 help here?
I've been having this same exact problem with my new monitor (1440p 240hz but set at 60hz). Every time I switch inputs or power cycle the Time Sleuth, I get very different results varying from 9ms to 25ms. Sometimes it also does that thing where it slowly trickles down to from 25ms to 9ms over a period of time and then jump right back up to 25ms. When I do powercycle/change inputs/change resolution, the average lag remains somewhat constant (outside of that slow trickle down) but the number is always different. I just sold my Leo Bodnar lag tester so I don't have another tester to compare it with so I've been going crazy if it's my new monitor is going nuts or my lag tester is going nuts.

This is the first monitor I've ever owned that does have a higher refresh rate than 60hz. The Time Sleuth never had any of these issues on the other 60hz monitors I've tested
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

Zerp wrote:
TrantaLocked_ wrote:Eatnumber1, I think I might be on to something too, with very similar results to your's although my Sharp TV does use PWM and the frequency is probably 120Hz or 240Hz based on reviews of similar TV models (1)(2). In my case the starting value isn't 100% stable like your's, but rather gravitates down at about .01ms / s until hitting a value near 22ms and staying there. I do think it's possible that it's due to refresh rate sync and not PWM in both our cases, with your 120Hz TV naturally having a 8ms range while my 60Hz TV having a 16ms range. I think that it's possible due to what the sync state is when the Time Sleuth pairs with the TV. At time of pairing, if the TS sends the output just after or just before the TV's most recent frame finished drawing (plus base input lag), or somewhere in between, that determines what the remaining time the TS output needs to wait for the current frame to finish drawing for the rest of the session, until power cycle for either TS or the TV. The minimum lag of my Sharp TV is 22ms, so to see a 38ms starting lag value, the first TS output would need to be sent just after ~10ms into the TV's second to last frame drawing before paring, and just before ~10ms for a 22ms starting value.

I've been power cycling the Time Sleuth and the TV in different combinations and have noticed what the starting values tend to be. The range of starting values for 720p is 22ms-38ms, and I believe the starting value is random (as it naturally should be, but certain conditions can lead to a higher likelihood of a particular starting value). In my case, the difference between 720p and 1080p is that for 1080p I see the full cycle play out within 10 seconds, but the other resolutions give me a more stable (but still changing) starting number. Maybe just the TV's PWM being different depending on input resolution. Could chriz2600 help here?
I've been having this same exact problem with my new monitor (1440p 240hz but set at 60hz). Every time I switch inputs or power cycle the Time Sleuth, I get very different results varying from 9ms to 25ms. Sometimes it also does that thing where it slowly trickles down to from 25ms to 9ms over a period of time and then jump right back up to 25ms. When I do powercycle/change inputs/change resolution, the average lag remains somewhat constant (outside of that slow trickle down) but the number is always different. I just sold my Leo Bodnar lag tester so I don't have another tester to compare it with so I've been going crazy if it's my new monitor is going nuts or my lag tester is going nuts.

This is the first monitor I've ever owned that does have a higher refresh rate than 60hz. The Time Sleuth never had any of these issues on the other 60hz monitors I've tested
I can explain this - I've seen the same thing using my home-grown PiLagTesterPRO. It's not PWM at all:

https://alantechreview.blogspot.com/202 ... g-and.html
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

In fact I've run into this drifting lag issue so much now that I've written up the cause in detail and even added a tool to measure it.

https://alantechreview.blogspot.com/202 ... -dont.html
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TrantaLocked_
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Re: Time Sleuth Lag Tester

Post by TrantaLocked_ »

xeos wrote:
I can explain this - I've seen the same thing using my home-grown PiLagTesterPRO. It's not PWM at all:

https://alantechreview.blogspot.com/202 ... g-and.html
What's crazy is how it behaves given a 59.94hz signal. You'd think the framebuffer would no longer be needed, or at least the TV would synchronize with the input. But it doesn't. Instead the TV starts drawing some fixed period of time after it's turned on, with no attempt to synchronize with the input's vsync. So one day your input lag will be 40ms, and the next it will be 51ms, and on your birthday it will be 35ms.
You have got to be f'ing kidding me. Honestly it is always something new to make me dislike TVs further, never anything that makes me like them.
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BuckoA51
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Re: Time Sleuth Lag Tester

Post by BuckoA51 »

I think the more we understand and shout about this the more likely something is to be done about it. Years back TV manufacturers could care less about input lag, but then a sizeable chunk of their customer base who play videogames made noise about it, review sites started talking about lag and we got companies like LG actually focusing on adding good gaming features.

The problem this time I suppose is that VRR etc would eliminate this issue but won't apply to older systems, which of course become niche so manufacturers care much less.
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

BuckoA51 wrote: The problem this time I suppose is that VRR etc would eliminate this issue but won't apply to older systems, which of course become niche so manufacturers care much less.
You don't need VRR - only about half the TVs I've tested show this problem. All the results in red are the type that have this problem:

https://alantechreview.blogspot.com/202 ... esult.html
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BuckoA51
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Re: Time Sleuth Lag Tester

Post by BuckoA51 »

You don't need VRR - only about half the TVs I've tested show this problem. All the results in red are the type that have this problem:
I think you misunderstand me. I know you don't need VRR to eliminate this problem, but a VRR equipped console and TV used together is guaranteed to eliminate this problem. My point is that, all a TV manufacturer needs do is include VRR and it will get a thumbs up as a great gaming TV from the mainstream media. It may be great for modern and future games consoles, but not so great for those of us playing older systems.
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SavagePencil
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Re: Time Sleuth Lag Tester

Post by SavagePencil »

Just got mine in the mail and I'm making sure I'm not doing anything stupid. I've plugged in HDMI and USB power. It is rendering correctly on the two TVs I have tried it on. However, the blue light only turns ON if the diode on the back is covered by my finger. It does not turn on when placed on the screen or when hanging in the air. The videos I've seen seem to show the blue light on all the time.

I've tried a second USB cable, same results.

Am I doing something wrong?
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BuckoA51
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Re: Time Sleuth Lag Tester

Post by BuckoA51 »

That's normal, as long as it's reading from the TV/monitor you're golden.
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SavagePencil
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Re: Time Sleuth Lag Tester

Post by SavagePencil »

It only seems to generate a reading when the diode is covered. I've tried on two different LCD TVs now, but let me keep poking at it.
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TrantaLocked_
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Re: Time Sleuth Lag Tester

Post by TrantaLocked_ »

Is it possible to add non-60Hz modes to the Time Sleuth? I would like to try 120Hz+ on my displays.
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Josh128
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Re: Time Sleuth Lag Tester

Post by Josh128 »

On mine, the blue light only flashes when the TS is reading a white flash from the screen. Away from the screen the blue light is not even on.
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

TrantaLocked_ wrote:Is it possible to add non-60Hz modes to the Time Sleuth? I would like to try 120Hz+ on my displays.
I think it maxes out at 60hz. Your options are the new leo bodnar 4k tester or the pilagtester pro.
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

ross wrote:Can anyone back the reliability of this or another lag tester with CCFL backlit LCDs? Seems like some were having issues earlier in the thread.
xeos wrote:For those of you who would like to measure lag but find the price of the timeslueth too high, how about free instead? I have a project that uses a raspberry pi zero to achieve the same thing entirely using software, no soldering required. If you don't already have a raspberry pi the zero model goes for about $5USD.

you can read about it here.

https://alantechreview.blogspot.com/202 ... berry.html
Based on comments on a linked post there, it sounds like this project is unusable now too unfortunately.
Most of the lag testers (all?) were designed when CCFL backlights were common, and in general it's not a problem. The backlight flicker can possibly/occasionally cause problems with the simplest lag testers like the time sleuth or the OSSC DIY that use a fixed threshold but in that case you'd get absurdly low lag values like less than 1ms so you'd know for sure that was the problem.

The https://alantechreview.blogspot.com/202 ... berry.html project is just as functional as the day it was released, not sure where you saw different? It does only work with the pi0 and other devices with the same GPU, not the pi4.
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WobblingPixels
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Re: Time Sleuth Lag Tester

Post by WobblingPixels »

I found this video testing the input lag of CRT and modern TV:

https://youtu.be/b3tbcUszA2s?t=55

I was suprised about the difference between CRT and modern TVs lag 7-8ms vs 12ms. After watching the video for the second time and I am even more confused:
Here is the lag measured by retrorgb with the OLED LG CX from the top of the screen which fits the stats posted by rtings:
https://youtu.be/_g-DOoizW_4?t=273
Same test with one of best CRTs from the top of the screen:
https://youtu.be/7VOsOuQ5mhM
...but when measuring from the middle of the CRT screen we get the exact number the video creator (above) mentioned 7ms:
https://youtu.be/HAddgkXwslY?t=170

So the difference at the end is 0.14ms with CRT vs 9-10ms modern TV (measuring top of the screen) and NOT 7ms CRT vs 12ms modern TV (or 9ms from rtings)?

I am correct or do I miss something?
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

ross wrote:
xeos wrote:The https://alantechreview.blogspot.com/202 ... berry.html project is just as functional as the day it was released, not sure where you saw different? It does only work with the pi0 and other devices with the same GPU, not the pi4.
Few comments here, one commenter using a 3B+ which has the same VideoCore IV GPU.

https://alantechreview.blogspot.com/202 ... 7022969241

May have jumped the gun though?
What a circuitous route to discover this issue! Apparently blogger spontaneously stopped emailing me about new comments several months ago.

Yes what they discuss is indeed an issue, as the OS libraries etc have been updated several times since that came out, and now KMS is the default video driver in some cases, I think, breaking everything. I suppose the right solution is to bundle up the entire package as a disc image bypassing any unwanted updates breaking things, though I'm running out of space to store such things in the cloud. Is this something you definitely want to be able to use? IF so let me know and I'll figure out a way to get it out there.
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Josh128
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Re: Time Sleuth Lag Tester

Post by Josh128 »

WobblingPixels wrote:I found this video testing the input lag of CRT and modern TV:

https://youtu.be/b3tbcUszA2s?t=55

I was suprised about the difference between CRT and modern TVs lag 7-8ms vs 12ms. After watching the video for the second time and I am even more confused:
Here is the lag measured by retrorgb with the OLED LG CX from the top of the screen which fits the stats posted by rtings:
https://youtu.be/_g-DOoizW_4?t=273
Same test with one of best CRTs from the top of the screen:
https://youtu.be/7VOsOuQ5mhM
...but when measuring from the middle of the CRT screen we get the exact number the video creator (above) mentioned 7ms:
https://youtu.be/HAddgkXwslY?t=170

So the difference at the end is 0.14ms with CRT vs 9-10ms modern TV (measuring top of the screen) and NOT 7ms CRT vs 12ms modern TV (or 9ms from rtings)?

I am correct or do I miss something?
CRTs TVs dont/cant store image data. The cathode rays turn on and off as the signal reaches them. The top left to bottom right scan is unchanging, therefore the source signal must be "synced" with the CRT scan. If a frame from a digital frame buffer is sent to the TV (say from an N64), it is first converted from digital to an analog 16ms long stream of alternating current, and CAN ONLY send the parts of the signal that must be displayed exactly where the scanning beam is at any given time, otherwise you get a f'ed up picture.

https://www.youtube.com/watch?v=3BJU2drrtCM&t=172s

Thats not the case with all CRTs though. CRTs used for oscilloscopes have beams that dont turn on and off, they are always on, only scan from left to right, at whatever frequency you set. Any input signal energizes the vertical deflection coil and pulls the beam in cadence with whatever signal is sent to it. Still CRT, but totally different operation from your standard CRT television or monitor.

https://www.youtube.com/watch?v=YJmtNxSqegA

Digital panels operate completely differently from CRT and from each other, depending on the type. Plasma for example, draws the entire picture simultaneously. OLEDs and LCDs can update their entire screen faster than 16ms, so a framebuffer from a source device can shift a new frame immediately, and all at once, depending on how the panel is designed. The source isnt required to stream the signal in sync with a scanning beam, as there is none.
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

ross wrote:Eh, don't bother, would probably only have been a temporary solution for my needs anyway
I did a quick check and it turns out I had left the software inside my more advanced piLagTesterPRO tool so I could easily compare results between the two methods. The executable lives on there to this day and still works. I updated the download page (https://alantechreview.blogspot.com/202 ... r-for.html) to reflect the full SD card image that should be used instead of the old and not-so-useful app only download, not necessarily just for you but for all of humanity ;-)
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WobblingPixels
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Re: Time Sleuth Lag Tester

Post by WobblingPixels »

Josh128 wrote: CRTs TVs dont/cant store image data. The cathode rays turn on and off as the signal reaches them. The top left to bottom right scan is unchanging, therefore the source signal must be "synced" with the CRT scan. If a frame from a digital frame buffer is sent to the TV (say from an N64), it is first converted from digital to an analog 16ms long stream of alternating current, and CAN ONLY send the parts of the signal that must be displayed exactly where the scanning beam is at any given time, otherwise you get a f'ed up picture.

https://www.youtube.com/watch?v=3BJU2drrtCM&t=172s

Thats not the case with all CRTs though. CRTs used for oscilloscopes have beams that dont turn on and off, they are always on, only scan from left to right, at whatever frequency you set. Any input signal energizes the vertical deflection coil and pulls the beam in cadence with whatever signal is sent to it. Still CRT, but totally different operation from your standard CRT television or monitor.

https://www.youtube.com/watch?v=YJmtNxSqegA

Digital panels operate completely differently from CRT and from each other, depending on the type. Plasma for example, draws the entire picture simultaneously. OLEDs and LCDs can update their entire screen faster than 16ms, so a framebuffer from a source device can shift a new frame immediately, and all at once, depending on how the panel is designed. The source isnt required to stream the signal in sync with a scanning beam, as there is none.
Thanks for detailed explanation.
How come that CRTs called zero input lag devices? ...and is the statement correct? The RetroRGB video shows its less than 1ms lag (which is considered to be "zero" lag) by checking the lag at the top bottom of the screen but watching the posted video here:
https://www.youtube.com/watch?v=b3tbcUszA2s&t=55s

...its 7ms messuring from the middle of the screen. What is the correct measuring method and figure? Does it depend on the CRT type?
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xeos
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Re: Time Sleuth Lag Tester

Post by xeos »

You can't go faster than the data is sent to the screen. So CRTs at 60hz will always have 7ms of lag at the center of the screen. Strictly speaking they are zero added lag screens.

You can send the data to the screen faster of course, and therein CRTs can differ in what the fastest refresh rates they take - most TVs were 60hz only, but high end desktop tubes could do 180hz at the end of the CRT era.
Deubeul
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Re: Time Sleuth Lag Tester

Post by Deubeul »

Hi, I post it here in addition to posting it in the trading station, because I think it will get more visibility here. Mods feel free to delete if it breaks the rules.


Hi,

The time sleuth lag tester being unavailable anywhere, I decided to built my own.
So I ordered 3 pcb on Oshpark, and soon discovered why the device is unavailable anywhere: the main chip is too.

So, if somebody here who built his own device has some spare
10M02SCE144C8G Altera chip, I'm interested in buying one (or three).

Thanks!
Johnpv
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Re: Time Sleuth Lag Tester

Post by Johnpv »

WobblingPixels wrote:
Josh128 wrote: CRTs TVs dont/cant store image data. The cathode rays turn on and off as the signal reaches them. The top left to bottom right scan is unchanging, therefore the source signal must be "synced" with the CRT scan. If a frame from a digital frame buffer is sent to the TV (say from an N64), it is first converted from digital to an analog 16ms long stream of alternating current, and CAN ONLY send the parts of the signal that must be displayed exactly where the scanning beam is at any given time, otherwise you get a f'ed up picture.

https://www.youtube.com/watch?v=3BJU2drrtCM&t=172s

Thats not the case with all CRTs though. CRTs used for oscilloscopes have beams that dont turn on and off, they are always on, only scan from left to right, at whatever frequency you set. Any input signal energizes the vertical deflection coil and pulls the beam in cadence with whatever signal is sent to it. Still CRT, but totally different operation from your standard CRT television or monitor.

https://www.youtube.com/watch?v=YJmtNxSqegA

Digital panels operate completely differently from CRT and from each other, depending on the type. Plasma for example, draws the entire picture simultaneously. OLEDs and LCDs can update their entire screen faster than 16ms, so a framebuffer from a source device can shift a new frame immediately, and all at once, depending on how the panel is designed. The source isnt required to stream the signal in sync with a scanning beam, as there is none.
Thanks for detailed explanation.
How come that CRTs called zero input lag devices? ...and is the statement correct? The RetroRGB video shows its less than 1ms lag (which is considered to be "zero" lag) by checking the lag at the top bottom of the screen but watching the posted video here:
https://www.youtube.com/watch?v=b3tbcUszA2s&t=55s

...its 7ms messuring from the middle of the screen. What is the correct measuring method and figure? Does it depend on the CRT type?
At 60fps it takes 16ms to draw an image on the screen. The way a CRT works is the electron beam is scanning from left to right and top to bottom. So its always going to be around 8ms at the middle of the crt screen.
sofakng
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Re: Time Sleuth Lag Tester

Post by sofakng »

Does anybody know if the Time Sleuth can be overclocked to output 1920x1440 (4:3 flag) ?

I'm trying to figure out a way to lag test this resolution on my LG CX/C1...
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orange808
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Re: Time Sleuth Lag Tester

Post by orange808 »

sofakng wrote:Does anybody know if the Time Sleuth can be overclocked to output 1920x1440 (4:3 flag) ?

I'm trying to figure out a way to lag test this resolution on my LG CX/C1...
I don't know of an easy way to perform that test.

It can be done using a video processor with known latency to upscale the Time Sleuth video. Unfortunately, machines that upscale above 1080p are expensive and difficult to find used. That's the most direct and easy way.

Alternately, you could try a camera test using a PC and two displays. You'll need to do some work to understand any inherent latency involved. Simultaneous synchronous output may not always be a given.
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