Using soX to extract channels and add silence

Add silence
Sometimes audio files are too short and does not match the length of the video files
Instead of making another reel with a silent soundtrack you can add some silence to the audio files using Sox.

To make a 48 khz 24 bit 10 second silent wav file with sox:
sox -n -r 48000 -b24 silent10sec.wav trim 0.0 10.0

To add this to the end of another 48 khz 24 bit sound file with sox:
sox film.LFE.wav silent10sec.wav film2.LFE.wav


Extract Channels

Extract channels from interleaved 5.1 sound files
If the file is L, R, C, LFE, LS, RS
sox film51.wav left.wav remix 1
sox film51.wav right.wav remix 2
sox film51.wav center.wav remix 3
sox film51.wav lfe.wav remix 4
sox film51.wav ls.wav remix 5
sox film51.wav rs.wav remix 6

Note: I had trouble with one interleaved audio file when making a DCP in EasyDCP Creator so I started extracting the channels on all interleaved audio files when making DCPs.

Note: You can check the interleaved audio file in Adobe Audition to see if it is L,R,C,LFE,LS,RS

In Ubuntu Linux you install sox using sudo apt install sox

On Windows you can install sox using Bash on Ubuntu on Windows and install sox with apt install sox or get the binaries from the Sox homepage.

On a Mac you can install sox using homebrew and install sox with brew install sox or get the binaries from the Sox homepage.

Using Ubuntu linux inside Virtualbox on a Mac to format hard drives and do other DCP related stuff

You can run linux inside virtualbox on a mac (and windows).
You can also run Windows inside virtualbox on a mac.

Installing Ubuntu in virtualbox 
Download Ubuntu

Download virtualbox and extensions

Install virtualbox
Click new
Choose Linux, Ubuntu 64 and a name like Ubuntu.

Choose RAM size. I used 2048 MB because it is recommended for Ubuntu 16.04

Choose Hard Disk size. I chose 15 GB and “create virtual hard disk file.”

Choose Hard disk file type. I left it at VDI.

Choose Storage on physical hard disk. I used fixed size because it faster.

Choose Location and size. Ubuntu


Choose Virtualbox – preferences – extensions and install the Virtualbox extensions you downloaded. The extensions enables USB 3.

I upgraded the settings on the Ubuntu virtual machine:

Ubuntu – settings:

ports – USB – USB 3

Video – Memory – 128 MB

System – Processor 2 CPUs (Ubuntu 16.04 minimum requirements)

Choose the ubuntu linux image when you boot it the first time or add is as a cd rom.

You can now start the virtual machine.

Choose install Ubuntu

I used the default settings.

When Ubuntu is installed you can install the linux Guest additions.

Use Virtualbox – Devices – Install Guest Additions. The Guest additions enables adjusting the screen size of the virtual box and other things.

Let the program run.

Choose shutdown

You can set up a Shared folder in virtualbox that will be mounted in linux
Devices – Shared folder – Shared folder settings

Start the virtual machine again


Updating Ubuntu

sudo apt update
sudo apt upgrade

You can copy files from EXT2 hard drives to Windows NTFS hard drives. NTFS hard drives can be read on macs.

Using Files/nautilus to access shared folders and copy files to EXT 2 hard drives.

You can start Files/nautilus as root to get read/write access.
in Terminal
sudo nautilus

Formatting a hard drive using Gparted

See this post for more info on gparted/parted/inode 128

run sudo apt install gparted to install gparted

Use Virtualbox – Devices – USB and enable the hard drive.

run gparted

sudo gparted

Click on “Device” – “Create a partition table”
Choose msdos.

Use add partition, add a label and format the drive as EXT2, NTFS, EXT4 or others.

Format the hard drive using mke2fs with inode 128
To format a hard drive as ext2 with 128 inode size, use this command in a terminal on the hard drive you want to format:
sudo mke2fs -t ext2 -I 128 -L DCP123 /dev/sdb1

Setting 755 permissions with chmod

in terminal
sudo chmod 755 -R /media/user/dcp/

Using asdcp tools

Download asdcplib

Extract it
Right click and choose extract here

Compile it
start a terminal in the asdcp folder
run these commands
sudo apt install libssl-dev
sudo ./configure
sudo make

Running asdcp-unwrap to extract the wav file from a mxf sound file
You can use asdcp-wrap to make MXFs

Open terminal in the folder where you want your wav file

Run asdcp-unwrap from the asdcp/src directory on the sound mxf file.

/home/user/Downloads/asdcp/src/asdcp-unwrap /media/user/dcp/sound.mxf

You can also drag the asdcp-unwrap file from the File manager to the terminal.
Then drag the mxf file to terminal.

The wav file can be imported in Adobe Audition.

Using Amazon S3 Simple Storage
Install Crossftp Pro to upload to Amazon S3 simple storage

Install java
sudo apt-get install default-jre
sudo apt-get install default-jdk
download portable crossftp and follow the instructions.
or download and install the crossftp linux deb package

change to the Downloads directory in Terminal or right click the directory and choose open terminal here.
open terminal
cd Downloads
sudo dpkg -i ./crossftp_deb_package.deb

Finding base64 sha-1 hash values
(You can also run this command in a terminal on a mac)

in Terminal:
openssl sha1 -binary "FILE_NAME" | openssl base64
source: wikipedia

Running Subtitle Edit in ubuntu.

You can run portable Subtitle Edit in linux. There is a discussion on the sub talk forum on how to run it.

You can run a basic version with video support. To do more advanced work I recommend using Windows. You can run Windows in Virtualbox on a mac.
You need to install mono-complete and Mplayer.
sudo apt install mono-complete
sudo apt install mplayer

If you open a video file in the Files/Nautilus file manager it asks if you want to install codecs.
I also installed these
sudo apt install vlc
sudo apt install mpv

Unzip the Subtitle Edit portable zip file
right click and choose extract here
In Terminal
sudo mono Subtitleedit.exe


Using Gnome Commander to copy files and set permissions

Install gnome commander
sudo apt install gnome-commander

run gnome commander
sudo gnome-commander

You can right click files and choose copy, then paste the files somewhere else.

You can right click files and check md5 checksums to check that files are copied correctly.


Should the DCI/SMPTE 431 digital cinema standards be updated for RGB LASER projectors?

Should the DCI/SMPTE 431 digital cinema standards be updated for RGB LASER projectors?

Higher contrast ratio

The SMPTE RP 431-2:2011 digital cinema standard document describes the reference projector viewing environments used in DCI digital cinemas.
SMPTE 431 Review room 14 fL, 100:1 Intra frame contrast, 1500:1 Sequential contrast
SMPTE 431 Cinema Theatre 14 fL, 100:1 Intra frame contrast, 1200:1 Sequential contrast

Most cinemas will see an improvement of contrast ratio and light levels with an upgrade to RGB Laser projectors.

This improvement will be noticeable on the DCPs used today.

Rec 2020 color space

New digital cinema projectors uses red, green and blue lasers as their light sources. They can (almost) reach the REC 2020 color space.

The RGB laser projectors also have better contrast ratio and can reach higher light levels without ruining the black level.

The DCI-P3 color space and 1200:1 contrast ratio in SMPTE RP 431-2 are based on what you can achieve with a Xenon lamp projector.

REC2020 covers 99.9 percent of pointer’s gamut, while DCI-P3 cover 91.4 percent. Source

This means that REC 2020 can do all the primary saturated colors, while DCI-P3 is more limited. DCI-P3 lacks Cyan.

Cinemas are also limited to colors that can be achieved with 14 fL.

It would be difficult to use an automatic algorithm to map some of these colors to DCI-P3 without changing the artistic expression of the film.

The Alexa SXT camera that is used on many films is compatible with REC2020


Barco White paper “What are ‘better pixels’?”

This Barco white paper from 1. february 2016 looks at REC.2020 and higher contrast ratio in cinemas with RGB laser projectors. They also recommend keeping the optical light path clean.

In practice, it turns out that some effort in reducing the auditorium reflectivity and lens glare (by e.g. keeping the lens and port hole clean of dust) can yield the same or better results than moving to HDR projection.


Dolby Vision and Imax Digital

You can watch RGB laser projection with (almost) REC 2020 color space and higher contrast ratios in Dolby Vision and IMAX Laser cinemas.
These cinemas can reach higher light levels and use bright colors that are not possible in ordinary cinemas.
Read a review of both here. 


A LASER IMAX system demonstration used an intra frame contrast checkerboard test image to show the intra frame contrast of their dual LASER projectors. They said in the demonstration that they changed the furnishing and changed the screen to get better contrast ratio.

Consumer products with P3 color space

Televisions UHD Alliance Premium requirements:

Image Resolution: 3840×2160

Color Bit Depth: 10-bit signal

Color Palette (Wide Color Gamut)

Signal Input: BT.2020 color representation

Display Reproduction: More than 90% of P3 colors

High Dynamic Range


A combination of peak brightness and black level either:

More than 1000 nits peak brightness and less than 0.05 nits black level

More than 540 nits peak brightness and less than 0.0005 nits black level

Apple is moving prosumer displays to the DCI-P3 color space. The first product is the Ipad Pro.  Source wikipedia.


Dual inventory of DCPs?

I think you can have two kinds of DCPs until all cinemas get RGB Laser or similar projectors:

RP 431-2:2011 DCPs for Xenon/UHP and Phosphor Laser projectors


RP 431-2:RGBLASER DCPs for RGB Laser projectors.

Dual inventory of DCPs is not a big problem.

DCP delivery services that uses fast internet to distribute DCPs to cinemas send the 3D DCP to the 3D cinemas and the 2D DCP to the 2D cinemas.  In the future if a venue have a RGB laser projector, it would be easy to send them the RGB laser DCP instead of the xenon DCP.

RP 431-2:RGB LASER REC 2020 could possibly use:

-REC 2020 color space,
-higher luminance
-and higher contrast ratio
inside the 12 bit 2.6 gamma X`Y`Z` JPEG 2000 250 mbit encoding used in today’s DCPs.
Or use the SMPTE ST2084 EOTF standard to be able to use higher light levels.

Upgrading the light path
Changing screen and furnishing to get good intra frame contrast is essential to good projection.

I discussed this in this post:


If the intra frame contrast is bad you could try to:
– Clean the port glass and optics.
– Avoid spill light from projection booth.
– Use matte black seats and furnishing.
– Install an iris in the projector.
– Upgrade to a laser projector.

A laser projector will be better at reaching today´s 3D light levels with just one projector and better at reaching today’s standard contrast ratio. 6P Laser projectors can use 3D with matte white screens and one projector.

A new RGB Laser standard could keep today’s light levels and contrast ratios and just add REC2020 color space. Or the standard could go beyond today’s values. RGB Laser projectors could manage higher values. But in a dark viewing environment higher luminance values can seem very bright.

The higher contrast ratio you could get with a laser projector could be ruined by reflective furnishing in the auditorium and other factors like old silver screens.

There should be a certification that cinemas could get to show that they are RP 431-2:2011(Xenon) or (future) RP 431-2:RGBLASER certified and have the correct intra frame contrast ratio and light levels.

Or they could get a certification that say they reach the correct light levels in 2D and 3D. (The cinemas should be able to reach these levels also when the lamp/lasers gets older.)

This way the public would know that kind of cinemas they can choose between.