Custom refresh rates for video?


#1

I think this has been asked before, but I don’t recall ever seeing a definitive answer…

Video will be one of the biggest driving factors for the 8k, so it’s essential that there is support for refresh rates other than the default 80hz. An option for 24hz/48hz/72hz (multiples of 24), and most importantly 60hz (since most high end VR video is shot at 60hz).

The Oculus Go figured this out, that’s why there is a 72hz mode.

@xunshu can we please get confirmation that these custom refresh rates will be supported?


#2

Imo multiple of 24 is not the most interessant because there is almost no video in 24FPS.

24 FPS was the speed of Film Camera. If there is still people shooting movies with this framerate even with digital camera, 24FPS is mostly use for DCP projection in theater. For consumers fiction video (Netflix, BD…) the framerate is 23,98 or 25 or 29,97 or 30.

So maybe 25/30/50/60 could be a better choice ?


#3

Like I said the most important is 60hz, but there is still a fair amount of older video shot in multiples of 24.

Me personally I would be happy with just a 60hz mode, but I can’t imagine it would be that much work to support other rates as well.


#4

is it that bad if the hmd is locked at 80hz and the movie is for example 60hz.

The question is should it even matter if the hmd HZ is higher then the content you play.

I mean i have a 120hz monitor, don’t seem to matter if i play games or movies, movies are most locked by the hz they
were shot at and games by the gpu power that drives up fps


#5

Higher is fine IF it’s a multiple of the original frame rate. Otherwise you get screen tearing and/or dropped frames.


#6

so 120hz is like a good setting that fits everything.

then why is the reason for 144hz monitors?
would 180hz not be more ideal when jumping from 120hz

And can we assume the standard for hmd should be 120hz eventually instead of 90hz.
Most people shout 90hz is a must, but it seems 120hz should be the standard…i know 90hz is for not getting suck etc, but for quality it seems higher is better

if i correc tthe playstation hmd is 120hz?


#7

Psvr is 60hz interpolated to 120.


#8

who what controls the fps/hz feed ,that is the question ,if its the headset asking for a sample then we are fine if the head set is being feed a sample we may see lots of missed frames .
i don’t know but it has to be one or the other,and of course how quickly your gpu can have a sample ready?
this may be total garbage but hay it makes some sense to me


#9

I wonder if the Netflix Test Pattern episodes would help see how the HMD interpolates video frame content?
https://www.netflix.com/gb/title/80018499


#10

@xunshu we still need an official answer on this.

Please don’t spend all this time delaying the release only to drop the ball on this key feature.


#11

Lower res = higher fps and visa versa


#12

@xunshu Any updates? …


#13

I think you’ve had plenty of time to ask one of the engineers… this is a pretty simple question…

Why no response?


#14

@xunshu Xunshu?

Any engineer should be able to answer this


#15

Reducing refresh for video viewing is not something I would recommend.

You are not so much displaying a film in the headset, but placing yourself in a virtual theatre.
Even if that virtual screen is just a screen in blank space.

If that immediate game world is behaving less like any other VR experience, people will get sick.
Even when sitting still, staring at a virtual screen.

What I find best to do when testing this in the Vive and CV1, was to use a virtual desktop software, like BigScreen in combination with SVP, SmoothVideoProject to increase the frame rate of the movie and reducing the fps scaling errors.

I’m sure somewhere someone will make a projection to work at source HZ, but the game world and the HMD itself need to remain at it’s designated high fps.

This is not an issue Pimax or any HMD manufacturer should bother themselves with, this is for the developer of the video player.


#16

That said.
BigScreen and to knowledge all virtual desktop applications projects the screen at it’s native refresh.

So for my watching a movie at say 23.9h8z etc, it is then scaled to match my 60hz monitor and then my monitor get’s scaled to match the HMD and the virtual world.
That could even be 45fps if you are in spacewarp, but luckily I hope to be able to manage at least 90 in a virtual theater.


#17

The conversion technology used in TV’s to match a films framerate (shot at 24 fps) to a panels Hz (often 60Hz) is called Telecine

John Carmack said the Oculus Go could switch from a native 72Hz (3 x 24 for a reason) to 60Hz for watching film.

30/60fps Video playback on the Pimax 80Hz could be jittery without some way of switching the Hz to a multiple of 30 and why other headsets are 90Hz native.


#18

Sorry Bob but I think you missed the point. Forget the virtual theater, we’re simply talking about the video stream itself. If the HMD refresh doesn’t match the source video framerate (or at least a multiple of the framerate, so it can display the same frame twice), then you will get a sub optimal playback.

@xunshu It’s been long enough. Please comment.


#19

Anyone going to be at the E3 demo tomorrow? Seems like confronting them in person is the only way to get an answer out of them.

In the words of Trump: Sad.


#20

I’m not entirely sure why your badgering xunshu After the M1 have gone out to beta testers for a feature that most likely is not even in the unit?! Have they Ever mentioned that it will have variable hz? Other than saying on the Kickstart page that they are aiming between 80-90hz?

This is the sort of thing that should of been discussed at V1 or V2 stage, or followed up at an earlier stage if it had been agreed with Pimax in an earlier update.

Let’s get the feedback from the testers before ‘demanding’ additional features.