RED One Configuration Overview

For using RED One signals with Previzion, there are two things to keep in mind: the sync from the RED preview output is different and the actual preview output is actually at a size of 1280x720px at 59.94Hz and 720p at 50Hz, in the case of PAL signals. In other words, regardless if you are shooting in 2K, 3K, 4K or 4.5K on the RED One, the preview output is always at a 720p size with a sync pulse of either 59.94Hz or 50.00Hz. The issue with having the camera output a sync of only 59.94Hz or 50.00Hz is that the Airtrack expects sync at the shooting rate.  This becomes especially problematic when using a frame rate of 23.978 or 25.

We recommend  two ways of solving this:

  • An external sync generator for locking both the Airtrack and the RED One (see RED One Configuration, Sync Generator at 23.98 PsF or 25PsF depending on the application).
  • A converter to bring the RED one video to a more standard format and derive Airtrack sync from this signal.


RED One Configuration
Sync Generator at 23.98 fps

When using the RED One, motion can strobe or look jittery.  In order to make the video signal proper and motion proper, use a Genlock source at 1080/23.98p (tri-level sync reference signal).  And SET PHASE TO 45.

There are a few options to generate sync source.  We recommend using a dedicated box, like the AJA Gen10.  We also recommend Sound Devices’ Pix 240i.

To set Phase on a RED One:

  • In the RED menu, navigate to SENSOR->SHUTTER->PHASE and advance the shutter phase by 45 degrees for correct sync.

When using an AJA GEN 10 or equivalent generator:

  • Select the option to generate a 1080p 23.98 reference (not 1080PsF).
  • This should be the signal feeding both the Airtrack and the RED One camera.
  • Run two separate feed to these and avoid splitting the signal.
  • The DIP switch setting on the back panel of the AJA Gen10 for 23.98p is:

    1. OUT 1-4: HD
    2. OUT 5-6: HD
    3. SD OUT: BLK
    4. FORMAT: 59.94
    5. HD FMT: 1080 or 720 (does not matter)
    6. S1: 0
    7. S2: 1
    8. S3: 0
  •  When the DIP switch is set to the above, and the GEN10 is connected to the Airtrack, the Airtrack’s Sync light will switch from red to amber, signifying the presence of a 23.98P (as opposed to PsF) signal. PsF signals generate a green sync light.
  • Set the frame delay under the Tracking tab to match the RED One (about 1.5 frames in our tests.)

RED One Configuration
Sync Generator at 25 fps

When using the RED One in 25fps, the output will be 720 in 50Hz.  For 1080×720 HD formats, 50p and 25p have identical video signals. Previzion is able to take this video input and convert it to 1920×1080 25PsF.

Like the setting about, you will need to generate a separate sync pulse to “Genlock” the Airtrack at 25PsF.  Use a Gen10 with the same settings as above, but with switch “Format” set to 50.

NOTE: that audio pass-through does not work with this format.

RED One Configuration
Format Converter at 29.97fps

For using RED One signals with Previzion at frame rates other than 23.98, we highly recommend up-converting the signal to a more standard signal that other professional devices understand.  For this, we recommend using a up/down/cross converter box like Decimator Design’s MD-DUCC, or equivalent, like MD-CROSS. In the RED menus, advance the shutter phase by 45 degrees for correct sync.  This is under “Sensor”, “Shutter Menu” and “Phase”.
The MD-DUCC is a converter box that might as well be the Swiss Army knife of video converters boxes.  It is an inexpensive and effective tool that we strongly recommend. For 25 fps, 29.97fps, 60i and so on, the procedure is essentially the same: up-convert the signal to 1920x1080px at the closest PsF rate.  Connect the MD-DUCC to the RED One preview output (720p) and, through an active loop, extract Airtrack’s required sync from this retimed scaled output as well as Previzion’s main output. For setting up a RED One at 29.97:

  1. Set your MD-DUCC’s “Scaled Output Format” to 1080/29.97PsF. This will convert the preview output from 720/29.97 @ 59.94Hz to 1080/29.97PsF.
  2. Extract Airtrack sync from this signal.
  3. In Previzion, select 1920x1080px – 29.97PsF.

The one tricky part of the MD-DUCC is its menu and settings which can be somewhat confusing. For a list of all the menus and settings, download it from:

NOTE: VANC (video time code) does not pass through the DUCC, the camera and Previzion will need to pull timecode from an external source. Also the factory setting for the output scaling is OFF. Please ensure that your MD-DUCC’s “Scale Enable” is ON. {{RIGHT}}

RED One Post

The RED One is unique in the sense that the field-of-view being recorded internally is different from the field-of view coming out its 720p/HD-SDI outputs.  In other words, RED Ones use a different sensor size for the live output than for the actual recorded image.

For example, when shooting 4K (16:9), the preview output will use a 24.192 mm sensor width, while the actual image uses a 22.118 mm sensor width. The live preview sensor width is about 109.375% the size of the internally recorded image.  The correct sensor size needs to be entered into Maya, Syntheyes, etc. for the data to track properly.

This difference varies when using Anamorphic resolutions (ANA) or the whole sensor at 4.5K WS resolution. Please use the tables below to reference the proper sensor size to input in your post-tracking software.

IMPORTANT:  The focal length is a property of the lens alone, and will not change.

Sensor Width

Red ONE cameras with the Mysterium-X (MX) sensor have the following sensor sizes:


RED ONE Mysterium-X format sizes:
 Recorded Resolution Resolution Name on RED One Menu  Recorded Sensor Width MON OUT Sensor Width
4480 x 1920 4.5K WS (2.33:1) 24.192 mm 24.192 mm
4096 x 2304 4K  (16:9) 22.1184 mm 24.192 mm
4096 x 2048 4K  (2:1) 22.1184 mm 24.192 mm
3840 x 2160 4K HD  (16:9) 20.736 mm 24.192 mm
2816 x 2304 4K ANA  (2:1) 15.2064 mm 16.308 mm
3072 x 1728 3K  (16:9) 16.5888 mm 18.144 mm
3072 x 1536 3K  (2:1) 16.5888 mm 18.144 mm
2112 x 1728 3K ANA  (2:1) 11.4048 mm 12.2688 mm
2048 x 1152 2K  (16:9) 11.0592 mm 12.096 mm
2048 x 1024 2K  (2:1) 11.0592 mm 12.096 mm
1408 x 1152 2K ANA  (2:1) 7.6032 mm 8.2944 mm


In Previzion, we use the widths in the “MON OUT” column.  But, when doing any type of post-tracking, make sure to use the sensor widths from “Recorded Sensor Width.”


Timecode Sync

The HDSDI preview output of the RED One will sometimes exhibit drift, even when genlocked. This will show up in the Previzion user interface as a red light on the Sync error panel, and an elevated frame rate (26 or 27 instead of 23.9-24.0). This can be corrected by stopping and restarting the incoming video.

Timecode Embedding

To enable timecode embedding in the output preview HDSDI signal, check the box in the Red menu: Project->Timecode->Output. You can verify the Previzion timecode sync with the Red timecode with Project->Timecode->Display.

Shooting High Speed

Red ONE cameras have the ability to shoot in variable frame rates.  However, the HD-SDI monitor outputs (Mon Out, HD-SDI Out) are always at a standard frame rate that Previzion can read.  This is often 24fps at 720p resolution or 25fps at 720p. The reason for this is because the camera’s monitoring  outputs must always be usable by regular HD monitors.  Since this is the same output that Previzion listens to, Previzion simply composites on the signal as a regular signal.