Playing Blu-Rays in a Cinema

Blu-Rays and H264 files are sometimes used instead of DCPs when screening special content at cinemas.

Modern Blu-ray players send the video and sound signal through the HDMI connection. When choosing which Blu-Ray player to use in a cinema/movie theatre you should first check if you need analog 5.1 sound output.

Many Blu-Rays only have DTS MASTER HD 7.1/5.1 sound. That means no Dolby digital 5.1 bit-stream that can be used on the SPDIF input on cinema audio processors like the CP-650.

Players with analog 5.1 sound can connect to the analog 5.1 input on most cinema sound processors.

To connect the 5.1 phono output to a Dolby CP-650 and other cinema equipment you need an unbalanced 5.1 Phono to DB25 cable.
Like this one:
db25

Some newer cinema equipment may accept the DTS HD Master bitstream from HDMI or 5.1 uncompressed sound from HDMI.

Other features that is useful in a cinema:
-Common height (CIH) settings
-Lipsync adjust.
-Remove On Screen Display
-Adjust Brightness/contrast
-Advanced film/video/cadence detection for DVD.
-H264 Media file playback
-Adjust speaker trim level
-LPCM output
-RS232 control

The OPPO UDP-203 4K Ultra HD Blu-ray Disc Player has these features according to the manual.

More info on the features that are useful in cinemas:

 

Common height (CIH) settings
Useful if you want to adjust the placement of subtitles on scope films in a common height cinema.
A common height cinema uses a 2.39:1 screen.
If the subtitles are “burned in” below the picture you can´t screen the movie in scope and need to either make a custom preset on the projector or screen it in Flat.

Lipsync adjust.
Adjusting the sync with a sync clip played from the blu-ray player is helpful if the sound is out of sync.

-Remove On Screen Display
If you don’t want to show the play and pause icons it is important to turn off OSD.

-Adjust Brightness/contrast
Badly mastered Blu-rays may have elevated blacks or bad white levels, this is corrected with the Brightness (black level) and Contrast (white level) settings.

-Source Direct mode
Turn of video processing. Sends a clean signal.

-Advanced film/video/cadence detection for DVD.
Can auto detect if the DVD source is progressive (film) or interlaced (video). Can fix bad cadence.

-Media file playback
You can play MP4 and other H264 formats from a USB flash drive.

Resolve 11 adds 12 bit monitoring support with the BlackMagic Decklink 4K Extreme and the UltraStudio 4K

12 bit monitoring is great when grading LOG for digital cinema (DCP) on a 12 bit digital cinema projector.

To have the correct black level and correct contrast ratio you will need the correct review room contrast ratio in the cinema: 1500:1, 100:1 intra frame. Movie theaters have 1200:1.

You will also need the correct white light level (14 fL) in the cinema to get the contrast correct.

You will also need a dark room.

See this post for more info on good projection.

Resolve 11 beta 2/Desktop Video 10.1.3 adds dual link 3GB HD-SDI DCI 12 bit monitoring with the Decklink 4K Extreme and the BlackMagic Design UltraStudio 4K

12-bit 4:4:4 video monitoring support with Decklink 4K Extreme and Ultrastudio 4K (up to Stereo 2K DCI)

-What’s new in Resolve 11 Beta 2
BlackMagic resolve website

How to make 3D LUTs in Nuke (R´B´G´to X´Y´Z´)

In this post there are more 3D LUTS

Updated in 2016 with some clarifications

The built in SRGB TO XYZ conversion used in some DCP conversion software do not have the correct color science.

See this post for more info.

The included XYZ 3D LUTs in this post are proof that you can generate 3D LUTs using the color science math from the REC709 example on page 42 in the “SMPTE Digital Cinema White Gamut Practices Study Group Report” by Rod Bogart and Rick Sayre.

The R´G´B´ values 4095, 4095, 4095 ends up as 3883 3960 4092 in X´Y´Z´

 

 

The “SMPTE Digital Cinema White Gamut Practices Study Group Report” (Linkfrom 2009 concluded that the color science used to make some commercial DCPs around 2008 was not correct (out of gamut).

The color science is explained more in SMPTE EG 432-1:2010

They explain how to use D55, D60, D61 and D65 as mastering whites and how these white points fit inside X´Y´Z´. They explain that DCI White is not necessary the mastering white.

With SMPTE 431.2:2011 they made a new projector configuration file (PCF) standard that is called Virtual White.

The DCI specifications  says that the projectors in cinemas should follow SMPTE 431.2:2011.

 

Update 2016

The color science math do get to X´Y´Z´ in this post produces the correct values for white in X´Y´Z.

In NUKE you can make 3D LUTs for Resolve and other software that have 3×3 SMPTE RP-177 color matrix conversions, gamma conversions and multiplications baked in.

The generateLUT node is now disabled in NUKE non-commercial (formerly PKL).

Links:
Nuke

http://help.thefoundry.co.uk/nuke/content/reference_guide/color_nodes/generatelut.html

Blackmagic Davinci Resolve

Example 1:
Making a REC709/SRGB R´G´B´to DCDM X´Y´Z´ 3D LUT for Resolve:

How to make a R`G`B` to X´Y´Z´ 3D LUT in NUKE:

 

-In the CMSTestPattern node I used a Cube size of 65, alternatives are 33 or 17.

-Linearize the R´G´B´ to RGB with a gamma function in a Gamma node: Example: 2.4 simplified gamma function= 0.416667
Alternative: SRGB 2.2 simplified gamma function=0.45

-Apply the rec709/SRGB RGB XYZ to RP-177 3×3 NPM color matrix in a ColorMatrix node.

The NPM from matlab after doing the RP-177 math is:
0.412390799265959 0.357584339383878 0.180480788401834
0.212639005871510   0.715168678767756   0.072192315360734
0.019330818715592   0.119194779794626  0.950532152249661

The middle row sums to 1.

The NPM after copying and pasting into the Nuke colormatrix node:

0.4123908  0.35758434   0.18048079
0.21263901 0.71516867   0.07219232
0.01933082 0.11919478   0.95053215

This is very similar to the example.

The middle row should sum to 1 according to RP-177 so I changed 0.71516868 to 0.71516867.

-Apply the normalizing constant multiplication in a multiply node. Luminance (48) divided by the normalizing constant (52.37) = 0.91655527
After pasting it into nuke it is shorten to:
0.916555

-Apply the DCP 2.6 gamma in a Gamma node to get X´Y´Z´ values.

-In the GenerateLut node I put: .3dl, 12 bit in/out, 3dl file format
autodesk flame/smoke.
Alternative: 16 bit.

The values for 4095,4095,4095 in the resulting 3D LUT (12 bit 3dl integer file) is:
3883 3960 4092

38839604092

This is the correct result for D65 in X´Y´Z´
and it is the same result as in the example conversion.

 

With this 3D LUT you are inside the Virtual white X´Y´Z´ gamut (DCI/SMPTE 431.2:2011 compliant).

To convert this 3D LUT to a floating point .Cube 3d LUT that is compatible with Photoshop, Resolve and After Effects I used opencolorio.
In terminal on a mac I use this command to convert the 3D LUT:

ociobakelut -lut srgbtoxyz.3dl -format iridas_itx -cubesize 65 srgbtoxyz.cube

to install opencolorio/ociobakelut I used these commands on a mac:

/usr/bin/ruby -e “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)”

brew doctor

brew install opencolorio

Download a 7z archive with the REC709/SRGB 3D LUTS files
It includes  2.2, 2.4, 2.6 CUBE and 3DL 3D LUTS (The cube 3d luts are in float)

Usage in Resolve (updated for Resolve 11)

The CUBE LUT can be placed in a folder you call Nuke or DCP inside Resolve´s LUT folder:
On a Mac: /Library/Application Support/Blackmagic Design/Davinci Resolve/LUT
On a PC: C:\ProgramData\Blackmagic Design\DaVinci Resolve\Support\LUT\

In Resolve you can apply it to the timeline from:
Project settings – Timeline Lookup tables – 3D Output Lookup table
or you can use a corrector node

You can render DCPs directly from Resolve with the Resolve Easydcp plugin. If you choose DCI X´Y´Z´ in the timeline color space no color transform will be applied and you can use the 3D luts to DCI X´Y´Z´ from this post.
See this post for more info.

Or export to another format and use it in Fraunhofer Easydcp .

Usage in After Effects
The resulting 3D LUT converted to .CUBE can be used in a non-linear 32 bit Adobe After Effects CC project
with the apply color LUT effect
when exporting 16 BIT TIFF or similar
or DCI jpeg2000 sequences with the Fnord DCI JPEG2000 encoder.

Usage in Easydcp
The 3DL 3D LUT can be applied in Easydcp.

In Easydcp Creator 2.2 you have the option to make custom color transformations. You can modify the 3×3 matrix, gamma, normalization constant/multiplication to suit your workflow. This is better than using 3D LUTs that has these color transformations baked in.
Read more about the custom color transformations in this post.

Example 2.

P3D65 to X´Y´Z´
The same example as I used in this post.
This 3D LUT can be used with Arri Alexa material that has the
C-log to P3 D65 3D LUT applied.
Link:Arri lut generator

 

Changed the color matrix node to:

The DCI-P3 D65 NPM from matlab after doing the RP-177 math:

0.486570948648216 0.265667693169093 0.198217285234362
0.228974564069749 0.691738521836506  0.0792869140937450
0                                               0.045113381858903   1.043944368900976

The NPM after copying and pasting into the Nuke colormatrix node:

0.48657095  0.26566769  0.19821729
0.22897457  0.69173852    0.07928691
0                             0.04511338    1.04394437

The middle row sums to 1
0.22897457+0.69173852+0.07928691 = 1

It is similar to the P3 D65 NPM from SMPTE EG 432-1-10

0.48657;0.26567;0.19822
0.22897;0.69174;0.07929
0.00000;0.04511;1.04394

Changed the gamma function node to 1/2,6=0.384615385 for P3
It becomes 0.384615 after pasting into Nuke.

Example P3 D65 to X´Y´Z´3D LUTS:

Download 7z archive with the P3 D65 3D LUTS files
It includes CUBE AND 3DL 3D LUTS (The cube 3DLUTS are in float):