[FFmpeg-user] telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

[Mark Filipak]

A transcript of my IRC with MPV developers is below. It's possible that when I set the TV to 
24/1.001Hz, the TV is actually receiving 24/1.001fps from the MPV player. Certainly the MPV player 
thinks so.

Result: The TV (or maybe the NVIDIA chip) is telecining. I get telecine judder when playing a 
fer-sure 24p test video. NVIDIA says 23.970Hz, Windows says 23.970Hz, MPV says 23.970Hz, MonInfo 
doesn't say (it only tells capabilities), and the TV's on-screen display doesn't say shit. The TV's 
manual says it's a 60Hz TV and doesn't say anything else. Still, the NVIDIA chip (which controls the 
display port) could be doing some 'friendly' lying to 'everyone else', eh? Sigh.

To the HDMI capabilities query, the TV reports only capability of 60Hz and input vscan range of 23Hz 
to 76Hz.


<markfilipak> Howdy. My TV is 60Hz. I assume that when MPV plays a 24p video, the OS (or NVIDIA GPU) 
telecines it to 60Hz. Is there a way to force 24fps? (I'm testing to see whether the TV also telecines.)

<sfan5> https://github.com/mpv-player/mpv/wiki/Interpolation#32-pulldown < this is what mpv does by 
default (your OS or GPU do not decide this)

<sfan5> if you want exactly 24fps to arrive at your TV switch the video mode to one that is 24p

<markfilipak> How do I switch the video mode?

<JEEB> it's usually called refresh rate

<JEEB> :P

<markfilipak> Yes, how do I switch it? Or are you saying that I need to send an HDMI command to the 
TV to do it?

<sfan5> well how do do that depends on your OS

<markfilipak> When I use NVIDIA to switch to 23/1.001, the TV will switch to 23/1.001Hz? Are you sure?

<markfilipak> When I switch and query the HDMI capabilities via MonInfo, they have not changed.

<sfan5> is this not what you expect? your TV will get exactly the framerate you wanted

<JEEB> on windows you can look at display settings etc :P 
https://kuroko.fushizen.eu/screenshots/mpv/lol_windows_hdr_24hz.png

<markfilipak> Hmmm... Maybe they do change. I'll have to check it again as it's been a long time 
since I tested that and I may be wrong. And since Windows crashes when I switch on the TV (currently 
off) I'll have to log out.

<JEEB> and mpv with shift+i will show the probed display FPS

<markfilipak> Okay, but MonInfo is way more verbose. But as I wrote, I have to shut down Windows and 
turn the TV on and restart Windows or it crashes.

<markfilipak> Bye. Stay safe and healthy.

=====

<markfilipak> Howdy, I'm back. I just want to confirm that having switched my TV to 23Hz (24/1.001, 
actually) via the NVIDIA control panel, and then playing a 24p movie, the TV is actually being fed 
24fps, that the NVIDIA chip is not doing telecine. Is this correct?

<markfilipak> Oh, I think I may be able to answer my own question: MPV, Shift-I shows "Display FPS: 
23.970 (specified)". Now, it is possible that the NVIDIA chip is intercepting that HDMI directive 
and fixing up a "23.970" answer, or the TV is responding (the NVIDIA chip is standing aside) and the 
TV is actually receiving 23.970FPS. In any event, the 24p movie is displaying telecine judder. What 
do 'you' say?

<JEEB> I'd say everything is possible, but most likely if the vsync is working correctly etc and you 
don't get frame drops etc - is taht the content just sucks

<JEEB> I have seen very few studios unfortunately do a proper job at making smooth transitions

<JEEB> or smooth spans, at 24Hz

<JEEB> I think ufotable was one of those animation studios where I could semi-expect to get a nice, 
smooth left-to-right pan

<JEEB> but generally, it's a crapshoot

<JEEB> real life camera content depends

<markfilipak> The source is 100% accurate from ffmpeg folks. To be sure, I also ran "Patton" BD, and 
I'm quite confident it is a great transfer to BD.

<JEEB> also why is that 24/1.001 "specified" therE?

<markfilipak> No dropped frames.

<JEEB> ah no, I also get that

<JEEB> :P

<JEEB> so that seems normal, and the screen seems to be operating at 24/1.001 as far as your desktop 
is concerned

<markfilipak> Ah, no... what?

<JEEB> the "specified" bit, I forgot how shift+i shows that :P

<markfilipak> Yes, if I can believe it.

<JEEB> specified vs found out

<markfilipak> "Display FPS: 23.970 (specified)" "FPS: 23.970 (specified) 23.970 (estimated)". I 
assume the later is the source video info.

<JEEB> yea

<der_richter> nah, it's the estimated display fps, source video is one line below "FPS:"

<der_richter> sry misread...

<markfilipak> Okay, I think that about wraps it up. This TV is 60Hz only (which is what I suspected) 
and it's doing telecine (hence the telecine judder). Thanks JEEB. Be safe, be healthy. Bye, and 
thanks again.

<der_richter> what kind of TV do you have?

<JEEB> yea you wish there was more stuff to be able to debug on which side of the fence you are :)

<markfilipak> Sharp LCD

<JEEB> many TVs are not exactly forthcoming about things

<markfilipak> Well, I query HDMI capabilities via the MonInfo utility.

<der_richter> okay no experience with sharp, but se if you can get it into "PC mode"

<der_richter> some TVs need the output to be called PC, for example

<markfilipak> What would PC mode do for me. Prey, do tell.

<der_richter> less TV processing, usually

<JEEB> markfilipak: I'm not 100% sure what that tells you? can you post an example of its output?

<JEEB> pastebin if it's multiple lines

<der_richter> nor overscan, if it doesn't have a separate setting for it

<markfilipak> You want me to post the source video? ...A single frame screen shot won't show judder.

<der_richter> i believe he meant the output of moninfo?

<markfilipak> I've never used pastebin. Hold on...

<JEEB> no, I was interested in MonInfo

<JEEB> what it actually can tell you

<markfilipak> Regarding Sharp LCD TV, MonInfo HDMI capabilities: https://pastebin.com/qyPfPFhi

<JEEB> markfilipak: yeh, that seems like indeed "the capabilities" so that doesn't actually  note 
the current configured mode etc?

<markfilipak> All it shows is capabilities. It's real time, but doesn't appear to show what's 
actually being set.

<JEEB> yup

<JEEB> using dxdiag or so to write a log file - or the windows display details do show the value 
that windows thinks it has configured

<markfilipak> Any ideas? You are the folks who would know. By the way, did I mention how much a 
adore MPV?

<JEEB> well, unfortunately the only way to really know things would be to probe from the TV side - 
and that's not going to happen unless you get access to some development mode

<JEEB> or debug mode

<markfilipak> Oh, I'll try the remote control... see what's up.

<JEEB> markfilipak: good luck, I don't even know that stuff for my TV :P

<markfilipak> The TV on-screen setup does say shit.

<markfilipak> Well, Windows says it's 23Hz, for what that's worth.

<markfilipak> Previously, I wrote "The TV on-screen setup does say shit." I meant to write The TV 
on-screen setup doesn't say shit.

<markfilipak> Well, JEEB, I see you're busy, so I'll go with the message that "It's indeterminate". 
Bye, and thanks.