Projector that can do 60fps 1080 at 120hz in 2D?

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stoc4341
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Joined: 19 Aug 2016, 15:54

Projector that can do 60fps 1080 at 120hz in 2D?

Post by stoc4341 » 19 Aug 2016, 16:05

Hi Everyone,

I’m a director working on a music video where we will be projecting videos onto actors. I have sped-up footage projecting onto the actors, then we film the actors in slow-mo at 120fps, and then the projections sync back to the music when we bring it back into a 24fps timeline. You can see test footage I shot where my girlfriend was kind enough to lipsync a Beach House song for me: https://vimeo.com/178842620/26375aa13d.

This test footage was shot using a cheap consumer projector and an A7Sii. We are going to be filming the final video using a RED Dragon. I’m posting here to ask for some advice on the type of projector to use for this project/how to best pull this effect off.

I would really like to remove the flicker that is obvious from filming a 60hz projector at 120fps (you can see it in my sample footage). I’ve been trying to see what options are out there for projecting at 120hz or if we can accomplish this effect another way. I’ve been asking around Reddit and FB groups for answers and have had some good input but no solid answers.

I’m asking here for any input on the theoretical methods listed below. I’m especially curious about hardware recommendations for projectors, servers, sync cards, sync generators, etc. Links to the projectors and their manuals would be appreciated.

If anyone has input, experience or, most importantly, a proven projector that can do 120hz at 1080, that would be awesome.
I’ll be reaching out to manufactures/rental houses as well today but I am looking forward to your thoughts!



METHOD #1 :Is there a projector that can project 1080 60p at 120hz in 2D?


Any suggestions? If so, does the processing in the projector truly accept a 120hz signal? Can it project it in 2D (not 3D)?
Also, the projector might not be the main limiting factor… A “digital cinema tekkie” on a FB forum told me:

“Projectors can do 120hz.... It's the servers that needs to match the projector ….Servers right now can hit 60hz if the server has four,1TB, 10k spin, Enterprise SATA drives in them. You can't use consumer drives in servers for the server will not accept consumer SATA drives... 120hz content is going to eat up HD space in an alarming rate, let alone playback factors. Thing is 120hz refresh rate from just the cache is going to be tricky due to how fast the storage can keep up with filling the cache without going into buffer underrun. If you can find 20k spin drives with mega internal cache, you might get lucky…. We use JPEG2000, which is a form of MJPEG, an uncompressed, or simply, raw video file.”

Furthermore:

“If the content to project needs a high data rate, I recommend a PCIExpress SSD solution, which can reach 1500mbps or high read speeds. This is more than enough bandwidth to play back most any uncompressed format and will be able to handle DCP spec like a walk in the park.This is the product I am thinking of: http://www.newegg.com/Product/Product.aspx…”

Finally:

“The other aspect to consider is to plug the camera and projector into the same power supply. Camera not on battery.”

Overall, I’ve heard that LCD projectors would be preferable to DLPs (especially older ones with the wheel) for this effect, but I’m not sure if this would apply to higher end DLPs, especially ones with LED or laser technology.

To be honest, this looks like the projector I need but I don’t think a flight to the University of Tokyo is in our budget, nor do I think they would let us film the production in their lab: https://www.youtube.com/watch?v=L8kjdObjZpY

METHOD #2: Can I use a 3D projector to get a faux 120hz?

Recommendations from Reddit/FB:

“One thing you may be able to do is use a 3d projector to get a "faux" 120hz. 3D can be 60hz, and because 3D is for 2 eyes, it is 120hz. The caveat is that is a frame packed signal. Frame packing is including the left and right image packed into one video frame with twice the normal bandwidth. Basically that means it isn't a "normal" signal. HDMI version 1.4b includes support for 1080p60 3D”
...So if a projector can do 1080p60 3D, you could possibly convert your footage into a frame packed signal (no idea if an editing/encoding program could do this and can think of one reason it may not work). Because you won't be using 3D glasses, you will just see all the frames. Because it wouldn't be stereoscopic images, it will look like 120hz (maybe) and not a blurry 3D mess.
... Some newer 3D is 144hz, so you may have to keep an eye out for that. If all else fails, encode the projected media in 3D with each eye the same content and set the projector to 3D mode.

...I think if you can find a 3D projector that fits the brightness and color requirements, that you can figure out how to project 60fps/120fps content from a high end media PC.

…. encode the 60fps file into a 3D field sequential file at 60fps per eye (make right eye and left eye input the same file, it will have the effect of making duplicate frames so that each frame is duplicated when output from the 120hz projection).

...If you can encode a 60p 3d file with the eyes both being the same content then he will achieve a 120hz projection, but not actually have 3d content or need 3d glasses :-)

...so it matches with the camera 120fps shutter, doubling every frame of a 60fps content to flash each frame twice.
...Thus, the left eye will be on the odd number of hz and the right eye will be on the even number of hz ...


Thoughts/suggestions on a 3D projector?

METHOD #3: Sync a camera and a projector:

Recommendation from Reddit: “Both AMD and Nvidia make add on cards for their pro line that will take in an external sync source and frame lock the outputs. Like this: https://www.bhphotovideo.com/c/product/ ... tml...Then you get a sync generator and send the sync signal to the PC that is running the projector, and to the camera (so the camera needs a sync in, genlock.) Then everything starts its frame at the same time and, no flicker from timing issues...I do not know if the displays side will sync as best it can to 120, if the sync generator will even do 120hz, or what the camera would do….”


Anyone have experience syncing cameras/projectors at 120hz?

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