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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » A hobbyist asks: how best to prepare material for a Barco DP2K-20C

   
Author Topic: A hobbyist asks: how best to prepare material for a Barco DP2K-20C
Guy Burns
Film Handler

Posts: 15
From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 06-19-2017 07:44 AM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
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 Panasonic GH3, and new stereo soundtracks. It's just a hobby, but I want to do the absolute best job I can.

All content enters Premier as sRGB, exits as H.264 Blu-ray (m4v format), and passes through Encore (without transcoding) to a Blu-ray disk. I then check it out on a BenQ W7000 projector in my home theatre  – 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, DP2K-20C, and the projectionist assured me that I can feed in my Blu-ray content via a HDMI input.

Different Gammas
My entire workflow is effectively in sRGB, from scanner (or GH3), to my iMac's monitor, through to my BenQ W7000 projector. However, Cinema projectors, I read somewhere, have a gamma of 2.6, and I assume they use the colour space I've seen in my list of Photoshop profiles: DCI P3 RGB (Gamma 2.6) 5900K. When, as a test, I applied that profile to a scanned image, there was a significant darkening.

In the questions below, I assume the HDMI input goes through an Integrated Cinema Media Processor before it gets to the projector. I will call that an ICMP.
 
Ques 1
Can the ICMP convert HDMI signals to the proper colour space for projection?

Ques 2
What is the colour space of a Barco DP2K-20C?

Ques 3
Assuming the ICMP can convert, is the conversion done automatically, or can the conversion be turned on and off?

Ques 4
What is the most failsafe way of preserving the look of my videos: me using After Effects to convert to the projector's colour space before encoding to Blu-ray, or leave the content as is and let the ICMP do the conversion?

Ques 5
Are technical manuals for the Barco DP2K-20C available? I couldn't find any on their website, just some short videos.

Ques 6
Is there a loudness standard for feature films, such that if I adhere to it, my soundtracks will have a normal volume in the cinema? At the moment, all my soundtracks are stereo, matched to ITU-R BS.1770-2, with loudness set to -23dB LUFS.

Basically, I want to be as little bother to the cinema as possible – so they'll have me back next time. Meaning: I'd like to turn up for the test run and have audio and video work as they should, with an absolute minimum of changes to the cinema's normal settings.

Thanks in advance for any suggestions to help this cinema novice.

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Dave Macaulay
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Posts: 1865
From: Toronto, Canada
Registered: Apr 2001


 - posted 06-19-2017 12:17 PM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
Hi:
Colour space discussion gets rather complicated when you have an ICMP or IMS, rather than the "old school" server with dual SDI video to the projector.
The ICMP/IMS is the part with an HDMI input. In this case the projector is always in DCI-P3 and conversion from Rec709 is done in the server. The Barco ICMP is pretty good at that, a Dolby/Doremi/NEC IMS not as good (the newest Doremi/Dolby firmware release notes suggest that's been fixed now?).
You can vary the gamma in one of these IMS's fairly easily, not so easily in an ICMP.
So: your disk should be authored as a normal one, in Rec709 colour. The server should do a decent job of presenting it. If the image doesn't look good, you're probably best to try and correct it in authoring - the cinema won't likely know how to make adjustments and probably won't want to if they do know how.
A 12C with an IMS or SDI server has two DVI ports (disabled with a Barco ICMP though), you can send image signal to one of them. That lets you use the projector's colour space conversion: it is more adjustable that the server's.
Audio is another difficult question. I don't know what level standards are used in DVD/BluRay production, but the sound levels from them are not outlandish when a studio disk is played through an IMS or ICMP. They decode audio to 5.1 in some recorded formats but I'm not sure which. If the site has a Dolby CP750 or any of several modern sound processors, you can send digital audio direct to the processor from the player (some have an HDMI pass-through, some have coax and/or optical inputs) and have it do the decoding of whatever digital format you pick: a CP750 will decode Dolby Digital, CP850 can do the other DOlby stuff (TruAudio?) - Datasat and others will also decode DTS digital. An older film processor can probably do ProLogic decoding from an analog stereo player signal... but maybe taking what the server gives you would be best with one of those.

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Guy Burns
Film Handler

Posts: 15
From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 06-19-2017 05:50 PM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
Thanks, Dave, for the comments. Most appreciated.

So, the HDMI signal will go through the IMCP and be converted from Rec709 to DCI-P3 in real time, and then presented to the projector. Is that correct?

You've picked up on the part that concerns me, when you said:

The server should do a decent job of presenting it. If the image doesn't look good, you're probably best to try and correct it in authoring.

I would have thought that for a piece of equipment as pricey as the Barco, the conversion would be top notch. And that leads to a few more questions…

Ques 1
Why might the conversion only be a "decent job"? Because it's being done on the fly, and corners are being cut?

Ques 2
If the quality of the conversion may be doubtful, I'm happy to convert myself before encoding to Blu-ray. But then I have the problem: how do I make sure that the operator has turned off conversion – is there some box he has to tick?

Ques 3
Should I should take two test disks with me?

• One in Rec709, and ask the operator to turn on colour conversion.
• One in DCI-P3, and ask the operator to turn-off colour conversion.

Ques 4
What would be the most suitable content on the test disks? I'm thinking of 20 seconds each of:

Clip 1… a calibration pattern for Blacks (levels 0 - 16).
Clip 2… a calibration pattern for Whites (levels 239-255)
Clip 3… a typical dark scene (grayscale or colour?)
Clip 4… a typical bright scene (grayscale or colour?)

Are the four items listed above, the most suitable?

Ques 5
I didn't see any mention in the Barco specs of accepting a frame rate of 23.976. And I've read that some film festivals and the Oscars only accept 24.00.

Does the Barco having a HDMI input imply that it will correctly display any legal Blu-ray frame rate?

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Carsten Kurz
Film God

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From: Cologne, NRW, Germany
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 - posted 06-19-2017 06:02 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
The main application of a DCI projector is to show DCPs, not Blurays.

The Barco's HDMI port will happily display all allowed Bluray frame rates.

On the ICMP, you can not disable color conversion. If you choose the HDMI input, it will apply rec.709 color conversion. If you play DCP, it will create P3-color.

You can always try to create a DCP yourself from AE or the Bluray master, and see wether it makes a difference.

http://dcpomatic.com

I'd say, take your Bluray disc to that theater and just try before you make things too complicated.

- Carsten

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Marcel Birgelen
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Posts: 1959
From: Maastricht, Limburg, Netherlands
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 - posted 06-20-2017 06:10 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
I think I would go the DCP route. Simply because you avoid all the possible hassles of first creating a Rec. 709 output on Blu-Ray, having it converted to DCI-P3 (The loss of color gamut between the conversions might be none to minor, but only if the conversions don't get screwed). Getting HDMI to work right often proves to be quite a challenge, especially with ad-hoc setups. Also, there is the additional hassle of getting sound right.

With a DCP, you can ensure the colors in there are as accurate as possible and there's also just a single color space conversion. Additionally, you can combine the sound right into the DCP.

Furthermore, the cinema is already set-up to play back DCPs, so they do not need to hook up any additional equipment and they can easily tie it into their existing automation, which will usually result in a more professional show.

The DCP-o-matic tool Carsten pointed at, is an excellent freeware tool to create a DCP from many different sources.

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Guy Burns
Film Handler

Posts: 15
From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 06-20-2017 09:53 PM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
Thanks for all the responses. Here's what I've garnered from your input:

1. To avoid complicating matters, I should use my Blu-ray player and disk, which I can fully test at home.

2. Colour conversion cannot be disabled on the ICMP/Barco DP2K-20C combination. Therefore, my Blu-ray must be in Rec 709.

3. However… the cinema is already set up to accept DCP input, so using dcpomatic to create a DCP version would more easily tie in with their equipment. Except that…

4. I have no way of testing a DCP at home.

Full-Length Test Run
The big problem is: I must have a full-length test run, either at home or at the cinema. And because no one is in the projection room (now that it's digital, it's all auto, set at the start of the week), I'm pretty sure I'd have to pay to hire the theatre and the projectionist if I wanted a full-length test run. That doubles the hire cost.

When I approached the cinema a year ago, they best they could offer for a free test run was the ten minutes after the local Film Society has its once-a-month showing. That's the only time the projectionist is guaranteed to be in the room – because someone gives a talk about the film beforehand, and so the projectionist has to be there to start the film when the talk finishes, and then tidy up at the end.

So, in the ten minutes between the film society audience starting to leave and the projectionist wanting to go home, I've got to fit in a comprehensive test.

That's the problem.

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Frank Cox
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Posts: 1573
From: Melville Saskatchewan Canada
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 - posted 06-21-2017 12:37 AM      Profile for Frank Cox   Author's Homepage   Email Frank Cox   Send New Private Message       Edit/Delete Post 
If you don't fully test it, then you won't know if it's going to work when you show it to your audience.

The only question remaining: Is it worth the costs involved in making sure that it will work, or would you rather be in a position of apologizing to your audience as they leave the show that never got started?

After you have decided that, the rest will fall into place.

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Carsten Kurz
Film God

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From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 06-21-2017 04:42 AM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
If you are concerned about your work and 10 minutes is all you get, the 10 minutes is all you get and you need to prepare to get along with it.

If you test YOUR Bluray on YOUR Bluray Player at home, you can at least be sure there are no major playback interruptions. So, make sure they allow you to bring and connect your Bluray player. Then, look through your disc for critical passages, dark/bright, colorful, loud/soft passages, note them down, and try to have them watched within that 10min timeframe.

Did you calibrate your BenQ projector at home?

As far as color conversion is concerned, rec709 is not your problem - you will have a hard time making a Bluray that is something else than rec709.

When using an existing Bluray Player or your own player at the cinema, there is a possible pitfall with full range or limited range HDMI signals. Make yourself familiar with this. The issue is not huge, but it may result in a milky picture, or in crushed blacks and blown out whites.

- Carsten

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Peter Foyster
Film Handler

Posts: 27
From: ROLEYSTONE WESTERN AUSTRALIA
Registered: Aug 2016


 - posted 06-21-2017 04:59 AM      Profile for Peter Foyster   Email Peter Foyster   Send New Private Message       Edit/Delete Post 
I create my advertising slides using DCP-o-matic and then test the DCP using dcpPlayer. For that matter I test any DCP I create using this program.
It was free at one time, however it is now $49.95 USD to purchase the full version. There was a time limitation on the free version.

Check it out at http://www.digitall.net.au/

I am sure that there is a host of other like programs however this is the only one I have tried and it works well for me.

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Dave Macaulay
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Posts: 1865
From: Toronto, Canada
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 - posted 06-21-2017 07:20 AM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
If the cinema uses a Barco "Alchemy" ICMP you can only use the HDMI input (or DP) for non-DCP shows. Don't worry about colour space conversion, it's fine. The projector is continuously doing colour correction to adjust for the individual differences in lamp, light engine, and screen colorimetry. REC709 to DCI-P3 conversion is trivial. The errors in Doremi's IMS conversion were minor and only studios doing critical colour work ever noticed the issue, a beta firmware version was available for them.
Alternative content shows are a pain for commercial cinemas, they aren't usually familiar with how to do them. It's next to impossible to do it on an automated schedule, an operator will be needed to cue up and start the player. Not projecting the player menu etc. is troublesome because the projector is usually the only didplay... adding a preview monitor with HDMI isn't easy.
A DCP is best.
But... creating a DCP from any standard video format with the right image settings and sound in sync is not super easy the first time you try, and the conversion takes quite a while on most computers. You should convert a short clip and test it to confirm you have the settings right before committing to convert a feature length project. Also, creating a distribution drive that the server will accept isn't entirely simple.

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Guy Burns
Film Handler

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From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 06-21-2017 11:38 AM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
I'm being overwhelmed with responses. Thanks. Here are my responses:

Frank Cox
If you don't fully test it, then you won't know if it's going to work when you show it to your audience.

It'll be fully tested on my home equipment, then partly tested at the cinema. The reason I put together our home theatre, the Jenny Wren Movie House…

http://www.mediafire.com/file/wm1yvs794x19kr5/The_Magic_Begins_2017.pdf.

… was to test my AVs to see how they stand up amongst the cinema classics. I use the classics as my film school.

If anyone posting here is ever in Tasmania, drop in for a movie and stay a few days. How's that for Tasmanian hospitality!

Carsten Kurz
Did you calibrate your BenQ projector at home?

The projector is calibrated once a year to make sure…

• Blacks are visible down to level 1,
• Whites are visible to level 254,
• and the SMPTE colour bar, when viewed through a blue filter, shows none of the complementary colours.

Nothing fancy, but it seems to work.

Carsten Kurz
…there is a possible pitfall with full range or limited range HDMI signals.
That's the reason I want to take along my calibration charts, Black and White, and make sure I can see Levels 1 and 254.

Aside from that, is it possible that the Barco could misinterpret the HDMI signals? I've never had a problem with my BenQ misinterpreting the HDMI signal from my two Blu-ray players.

Peter Foyster
I create my advertising slides using DCP-o-matic and then test the DCP using dcpPlayer.
Thanks for the link to dcpPlayer – but it's PC only (I'm on Mac). I'll look into OSX players just in case I decide on DCP.

David Macaulay
Alternative content shows are a pain for commercial cinemas…

That's why I'm asking questions here: I don't want to be a pain to the cinema. I want them to consider me a cash cow. They get $500 from me (I hope that's close to the figure), plus I'll offer them a share of the takings. All they have to do is set aside a theatre from 7.30 till 10 pm on a Monday night, count the money, plug in a HDMI cable, and press play.

Is that scenario likely to be painful for the only cinema (4 theatres) in a town of 20,000 people – or a pleasure? I hope the latter. I've been in the theatre on weekdays when it's been just me and three others watching the movie. How do they make money doing that?

David Macaulay
Not projecting the player menu etc. is troublesome…
I thought I could ask the operator to fire up the player 5 minutes before the doors open. The splash screen comes and goes, leaving my Blu-ray with its 'Start' button as the only thing on screen. Or I could make the 'Start' button invisible so the audience sees just a black screen.

David Macaulay
But... creating a DCP from any standard video format with the right image settings and sound in sync is not super easy the first time you try… Also, creating a distribution drive that the server will accept isn't entirely simple.

David, you've just about convinced me not to even try the DCP route. But I've posted on the DCP-o-matic forums anyway, asking how difficult it is for a beginner.

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Carsten Kurz
Film God

Posts: 3096
From: Cologne, NRW, Germany
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 - posted 06-21-2017 09:03 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
quote: Guy Burns
Aside from that, is it possible that the Barco could misinterpret the HDMI signals? I've never had a problem with my BenQ misinterpreting the HDMI signal from my two Blu-ray players.
You can never be sure wether a HDMI signal range auto detection works properly. If you bring a test disc and know what to look for - okay. You need to make yourself familiar with the player setup menu to set the HDMI signal range options manually if needed.

For stereo audio, you should be okay with whatever means the booth has to play audio from Bluray.

- Carsten

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Guy Burns
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From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 06-22-2017 05:18 AM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
Thanks, Carsten, for the clarification about HDMI levels. That's led me to worry about something else – I'll have to find out if my Oppo can lock out all changes before I take it to the Cinema, just in case I press the wrong button and a setting gets altered.

How many more things can go wrong with a HDMI presentation?

I'm starting to see the advantages of using DCP.

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Carsten Kurz
Film God

Posts: 3096
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 06-22-2017 07:12 AM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
I think that Alchemy is pretty good in that sense that it is a fairly recent device and does in fact offer a HDMI input, not just DVI. HDMI MAY be a bit problematic in cinemas, because most cinemas do not use HDMI on a daily basis. You may sometime end up in a cinema where there is no bluray/DVD player at all, or the HDMI input has never been used (much) before, and you should not always expect knowledgeable staff in a cinema nowadays.

But in general, you should expect a Bluray presentation work just fine. I know many people have configuration issues with their home video setups just as well. Auto does not always work the way it should.

- Carsten

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Monte L Fullmer
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From: Nampa, Idaho, USA
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 - posted 06-22-2017 06:57 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
At my cinema,we do event rentals where clients want to show video content on the screen.

With DCP-o-Matic, I create their presentations from the MP4 files that are stored on thumbdrives that are given to me.

With doing DVD and BR, prob be best to rip the video from the disc prior to DCP conversion.

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