How can I validate that the display actually is 23.976 Hz?

[Sunspark]

I'm testing an old 1366x768 TV here, a review of it says the 24 Hz mode doesn't work right but it is listed in the manual's specifications so it was meant to be able to do something.

I am able to send it a 1920x1080 23.976 signal and the MadVR HUD will report that the display refresh rate is 23.976 as well as the Windows composition rate. Windows 10 also confirms that the refresh rate is as such.

I am also able to define this refresh rate on my monitor which was never advertised for it either.

I can see that mouse movement is jerky which is what I would expect to see, but is there a way I can properly tell without a fancy camera that the TV (or monitor) actually is working at 23.976 and not just holding and releasing frames in intervals?

Do we just take it on faith that the display actually is at that refresh rate? The TV is old and doesn't show the refresh rate, and the monitor once it is outside of native resolution doesn't show the refresh rate either.

[wonkey_monkey]

I would try sending it a strobing video, black and white frames interleaved at 24fps. If there's any mismatch it should become apparent when occasional frames are displayed for too long.

*Not if you have photosensitive epilepsy though.

[Z2697]

Use slow shutter speed to capture something moving fast and has consistent speed on screen

[huhn]

if sm plus 60 is smoother then 23p then 23p isn't working.

or just bye eye most tv that fail at 23p do 3:2 which is trivial for the human eye to see.

[Emulgator]

Plus a very simple approach here from 2003, if that TV can be set to be the Windows extended desktop.
On a black screen (my desktops are always black) move your cursor quickly in cycles, ellipses, whatever your fingers on touchpad or mouse will produce.
Missing positions will stand out like a sore thumb. (This exhibits other windows-graphics induced presentation faults too.)

Additionally you may shoot video using any modern mobile phone in HFR mode and framestep the result in VD.
But be warned, these smartphones may produce VFR.

Which one is it, BTW ? I remember to have a 2003-ish Samsung LW15C23EB (15" 1366x768) sitting around somewhere.

[StainlessS]

On a black screen (my desktops are always black)

Me too, also saves battery on tablet/laptop.

[SeeMoreDigital]

Hmmm...

As people may or may not be aware... Content encoded at 23.976fps can't be accurately displayed at 24Hz only at 23.976Hz - If forced you'll see something that looks like a dropped frame every 40ish seconds or so. Only content encoded at 24.000fps can be accurately displayed at 24Hz.

A good smart TV should be able to accurately process and display 23.976fps content at 23.976Hz along with 24.000fps content at 24Hz. European models should also be able to process and display 25.000 and 50.000fps pure interlaced and progressive content at 25Hz or 50Hz.

[huhn]

the core source for the issues is that 23 and 24p where broken on many many device back int he day and the TV was just doing 60 HZ with these signals.

and at the end nothing can be playback at anything cause the audio clock disagrees.

[SeeMoreDigital]

Agreed...