Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Hardware & Software > Hardware players

Reply
 
Thread Tools Search this Thread Display Modes
Old 28th March 2021, 05:41   #1  |  Link
bxyhxyh
Registered User
 
Join Date: Dec 2011
Posts: 354
Question about image quality of cinema projectors

Hello guys,
I got hired as a projectionist in a cinema in Mongolia.
Not really have experience in the tools of cinema tbh.

Are those projected movies supposed to look like pirated ones? like those movies recorded on camera from cinema?
Like that it has slightly low brightness and low contrast and looks like it has "wrong" black level

I thought they would look on par or even superior to bluray versions.

No matter how I set my focus and zooms it doesn't actually affect anything as I'm pretty sure that it isn't about zooms and focus.

Maybe screen quality thing, lamp problems or image settings of projector?
Or is it supposed to look like that from the beginning?

I don't have authority to play with image settings of projectors (actually I have if I read my job description, but higher-ups don't let me do and I'm also afraid of those expensive projectors lol.)

Projector is Christine CP4220 btw

Last edited by bxyhxyh; 30th March 2021 at 12:22.
bxyhxyh is offline   Reply With Quote
Old 30th March 2021, 01:59   #2  |  Link
Emulgator
Big Bit Savings Now !
 
Emulgator's Avatar
 
Join Date: Feb 2007
Location: close to the wall
Posts: 984
At 22k Lumens for a new 3kW Hi-Power lamp the max. contrast ratio of 2000:1 would still leak 11 Lumens onto the screen.
Depending on the screen size and reflectivity (screen gain) one will end up with, well, not pitch black.
Max. Brightness: Expect 50% loss after 1500 (3kW)..2500hrs (2kW) lamp life, you may want to read that out from Lamp History.
Dirt ? Open housing, expect to have filters replaced / reflector / lens cleaned.
__________________
"To bypass shortcuts and find suffering...is called QUALity" (Die toten Augen von Friedrichshain)
"Data reduction ? Yep, Sir. We're working on that issue. Synce invntoin uf lingöage..."

Last edited by Emulgator; 30th March 2021 at 02:56.
Emulgator is offline   Reply With Quote
Old 1st April 2021, 15:47   #3  |  Link
bxyhxyh
Registered User
 
Join Date: Dec 2011
Posts: 354
I don't think dust is the issue there.
There is a dust suction system in the projector box, me and other projectionists clean it every month with compressed air.

So I checked lamp history and it was used for 1900 hours.
Lamp was CDXL-20 model that has 9000 lumen and has an average life of 3500 hours and warranty of 2400 hours.

I expected a lamp to be the cheapest fitting for the projector.
But still, a bit disappointed tbh.

it's bummer that I wanted to watch Godzilla vs Kong with a good quality.
bxyhxyh is offline   Reply With Quote
Old 7th April 2021, 23:11   #4  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 1,408
Quote:
Originally Posted by bxyhxyh View Post
Are those projected movies supposed to look like pirated ones?
No? xD

Quote:
Originally Posted by bxyhxyh View Post
I thought they would look on par or even superior to bluray versions.
They're way better than any BD you can buy, even the UHD ones. You see, the masterfiles we send to theaters are 4K files in MJPEG 2000 250 Mbit/s in XYZ (yes, XYZ, not YUV) 4:4:4 12bit planar encoded from a series of lossless .tiff images (each frame is a still) in the DCI-P3 colorspace.
The Motion JPEG2000 basically uses the Wavelet Transform which is peculiar 'cause, instead of dividing each and every frame in block and macroblocks of pixels (like H.264 or H.265 do with 4x4, 8x8 etc) it applies the Transform to the whole frame. Oh and they're also Intra in the sense that "reframe" and GOP don't really make sense as each .tiff is encoded to .j2x and then is "appended" together and muxed in an .mxf container, so there are no motion estimation errors or other things. As to the audio, it's a discrete (each ch corresponds to 1 file) lossless PCM 24bit muxed in .mxf coming straight out of the mixer, all delivered as a DCP (Digital Cinema Package) which is essentially a folder structure with other folders, what else do you want? xD


Quote:
Originally Posted by bxyhxyh View Post
it's bummer that I wanted to watch Godzilla vs Kong with a good quality.

Well, I'm not really an expert about projectors as it's not my field and once I've sent the file to the theaters, my job is done, however... well... if you really really want to watch the movie you like and they have a room connected to the playback server, you could play the masterfile on a monitor instead of using the projector after your shift is over.


(Please note that I mean at your workplace in an approved room, do NOT try to get the masterfiles with something stupid like an external USB HDD, that would be just stupid and you would not only get fired but also get prosecuted)
FranceBB is offline   Reply With Quote
Old 15th April 2021, 23:05   #5  |  Link
bxyhxyh
Registered User
 
Join Date: Dec 2011
Posts: 354
Quote:
Originally Posted by FranceBB View Post
Well, I'm not really an expert about projectors as it's not my field and once I've sent the file to the theaters, my job is done, however... well... if you really really want to watch the movie you like and they have a room connected to the playback server, you could play the masterfile on a monitor instead of using the projector after your shift is over.


(Please note that I mean at your workplace in an approved room, do NOT try to get the masterfiles with something stupid like an external USB HDD, that would be just stupid and you would not only get fired but also get prosecuted)
Master files are kept in our main office which is not in my local city. Even if i go there, i have zero authority to watch it.
Files sent to our theaters can only be run with the help of a KDM file on allowed devices. So...
I can't watch it anywhere but on our cinema screens.
I also think that Hollywood studios wouldn't send their unprotected files to here.

Yeah, bummer lol.
bxyhxyh is offline   Reply With Quote
Old 15th April 2021, 23:48   #6  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 1,408
I see... Well that's unfortunate...
I guess you're stuck with the cinema screens then...
What I noticed about cinema screens when I released my first movie, by the way, was that it was way "softer" than I expected, however the good thing was that it was also much smoother than I expected.
I don't know why, maybe it's the fact that it's just reflected light rather than light coming out from a screen or maybe it's because of those tiny little holes on the surface you project the picture to... I don't know...
(Check my point 6 here if you're curios)

Last edited by FranceBB; 16th April 2021 at 00:00.
FranceBB is offline   Reply With Quote
Old 16th April 2021, 07:00   #7  |  Link
bxyhxyh
Registered User
 
Join Date: Dec 2011
Posts: 354
Quote:
Originally Posted by FranceBB View Post
What I noticed about cinema screens when I released my first movie, by the way, was that it was way "softer" than I expected, however the good thing was that it was also much smoother than I expected.
I don't know why, maybe it's the fact that it's just reflected light rather than light coming out from a screen or maybe it's because of those tiny little holes on the surface you project the picture to... I don't know...
(Check my point 6 here if you're curios)
That softening effect seems to be caused by bad installation or configuration of Projectors. At least I thought this way.

We have 3 projectors and all of them look different.
So after my shift I played with the all settings and all.
On one screen, movies look sharper than other two, and one look more ellipse-ish etc...

Blurriest one of ours were misplaced, too far from the screen, maybe a bad calculation on 'wall to screen' distance when they were building.
Box that contains projector can't go any directions, it's locked up there.
So they increased the zoom settings too much to fill the screen but that ended up hurting sharpness. And they maxed focus settings to one end to make it "acceptible to watch". Still looked very blurry.

Then i had to zoom out a bit to make it good enough. But image became noticengly smaller.
And those "sound go through" tiny holes seem to make it bit darker (just my speculation).
Same could be said to other cinema theaters.

Oh btw, Mongolian movies sometimes come as 3840x2160 or 1920x1080. IDK, maybe they don't know about cinema standard or something.
Then our "lead engineer guy" (I guess, i'm working here only for few months) creates DCP files from it. He crops and upscales the movies.
I have no idea why he does that instead of just adding black bars.

I happened to know that, our local movie making company gave me a trailer, that has 1920x1080 resolutions to make it air on screens.
Since I have no access to DCP creating apps, I just sent it to the main office But it ended up getting cropped from upper and bottom part then upscaled to 2k flat resolution.

It's beyond me, why did he chose to do that.
It bothers me little sometimes.

Last edited by bxyhxyh; 16th April 2021 at 10:47.
bxyhxyh is offline   Reply With Quote
Old 16th April 2021, 11:51   #8  |  Link
FranceBB
Broadcast Encoder
 
FranceBB's Avatar
 
Join Date: Nov 2013
Location: Metropolitan City of Milan, Italy
Posts: 1,408
Really? They don't send you DCPs?
Any re-encode made would be unthinkable over here in Europe. They want the file to follow the specs and I guess they would be pretty pissed if they were going to receive a ProRes at an arbitrary resolution, framerate, bit depth and in YUV instead of XYZ.
About the blurriness, it might be, I don't know... Again I'm not really familiar with those but I was pretty shocked to see the difference between the 50k€ Sony Reference display at work and the pictures on the cinema screen...
About the holes, I have no idea either... It would be nice if an expert on projects could jump in and enlight us with a technical explanation 'cause I'm curious now...
Anyway, good luck with your job, I hope it's not gonna be just a temporary one.
Oh almost forgot, if you're looking for open source DCP solutions, you should really check out Open DCP.
FranceBB is offline   Reply With Quote
Old 17th April 2021, 00:25   #9  |  Link
bxyhxyh
Registered User
 
Join Date: Dec 2011
Posts: 354
Quote:
Originally Posted by FranceBB View Post
Really? They don't send you DCPs?
Any re-encode made would be unthinkable over here in Europe. They want the file to follow the specs and I guess they would be pretty pissed if they were going to receive a ProRes at an arbitrary resolution, framerate, bit depth and in YUV instead of XYZ.
Some are fully equiped with professional gears and professional video and sound engineers while some poor ones don't so...

Quote:
Originally Posted by FranceBB View Post
Oh almost forgot, if you're looking for open source DCP solutions, you should really check out Open DCP.
Thanks, I'm gonna check it.

Quote:
Originally Posted by FranceBB View Post
Anyway, good luck with your job, I hope it's not gonna be just a temporary one.
Thank you. I hope so too.
Wish you good luck as well.
bxyhxyh is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 19:09.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.