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Audio-visuals shown at a cinema: what might be the problems?


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#1 Guy Burns

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Posted 13 June 2017 - 01:59 PM

Background

I'm converting my three-screen audio-visuals to Blu-ray format, with the aim of presenting them at the local cinema. Basically they're slide shows from the 80s and 90s, with a few added clips from my GH3, and new soundtracks. I'll let a few friends know, and they can pass the word around.

 

It's just a hobby, but I want to do the absolute best job I can. Editing is in Premiere at 23.976 fps, and all slides enter Premiere in sRGB. Video output if rendered to m4v format at 20-35 Mbps, and passes through Adobe Encore (without transcoding) onto a Blu-ray disk.

 

What I see on my iMac screen is pretty much what I see on our 3-metre home theatre screen – my test bed.

 

 

At the Cinema

What I am concerned about is how the presentations will look and sound in the cinema. I've had a short tour of the projection room. They run four Barco projectors…

 

https://www.barco.co...5ft.aspx#!specs

 

… and the operator assured me the setup can accept HDMI input. So my idea is to take along my Oppo Blu-ray player,  a HDMI cord, and have a test run. I will only be allowed 5-10 minutes of testing.

 

 

Questions

​Before I go to the cinema for a test run, I want to have a pretty good idea of what to expect, and where problems might occur. Thus these questions.

 

Ques 1: HDMI

The Barco processor has one HDMI input, but the specs make no mention of a 23.976 frame rate. Does having a HDMI input imply the Barco will work with all signals from a Blu-ray player, including 23.976 fps?

 

 

Ques 2: Gamma

My entire workflow is in sRGB (with a gamma of ~2.2), from scanner (or GH3), to my iMac, through to my BenQ W7000 projector. However, Cinema projectors, I read somewhere, have a gamma of 2.6.

 

What effect will that have on my images?

Will the effect be noticeable?

Should I correct for it?

How would I correct for it?

 

 

Ques 3: Test Material

The best test material would of course be the actual presentation, but I'll be limited to only a few minutes of projector time. My idea is to take along on Blu-ray disk:

 

1.  A projector Calibration Pattern for Blacks (levels 0 - 16).

2.  A similar pattern for Whites (levels 239-255)

3.  30 seconds of a typical dark scene

4.  30 seconds of a typical bright scene

 

Items 1 and 2 are not for calibrating the Barco, of course. If levels 0-16 all appear black, say, I'll have an indication that something's not right.

 

Are the four items listed above, the most suitable?

 

 

Ques 4: Sound

Is there a loudness standard for films?

 

All my audio is matched to ITU-R BS 1770-2. My guess is that the cinema runs a constant volume setting on their amps, a setting which suits most films. And I'd rather not ask them to change that setting just for me.

 

 

Thanks in advance for any comments.


Edited by Guy Burns, 13 June 2017 - 02:07 PM.

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#2 Satsuki Murashige

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Posted 13 June 2017 - 02:50 PM

If possible, hire a post sound mixer with a home studio to run it through their system and tweak the levels at least. They should at least have a 5.1 setup that approximates the movie theater.

No idea about the video settings, sorry. Your test sounds like a good idea. Maybe also test to see if you can simply plug in your laptop directly to the HDMI on the projector. Just in case the Blu-Ray player doesn't work.
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#3 Guy Burns

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Posted 21 June 2017 - 12:35 AM

Thanks, Satsuki, for the suggestions.

 

Since I've had limited response here, I've taken my questions to the Film-Tech forum (http://www.film-tech...16/t003048.html), and they've provided some detailed suggestions.


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#4 Michael LaVoie

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Posted 21 June 2017 - 07:17 PM

Most bluray players have a USB port for playing files directly from a flashdrive.  That's always more reliable than an actual disk.

 

I've traveled to screenings with a backup projector at times just in case and have had to use it on more than one occasion.  


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