RED Epic/Scarlet Connections

Most often, when a camera manufacturer writes that their output is 23.98p, they actually mean that it outputs 23.98PsF.  The Red Epic, however, actually outputs a 1080/23.98p (not PsF) output.

As of Build 6466, Previzion’s 1080/23.98p video format setting takes this signal directly and outputs it without any video conversion.  In other words, Previzion takes in a “p” signal and outputs a “p” signal.

Previzion also supports 1080/25.0p  and 1080/29.97p inputs.  This discards the need for any video converter boxes in virtually all RED Epic/Scarlet applications.

EPIC at 25fps and 24fps

It is important to note that, unlike the RED ONE camera, RED EPICs have an extra setting for its HDSDI output that needs to be changed whenever going from 24fps to 25fps and vice versa.

An indication that your timebase is off will be to see “timecode repeating” flashing in random intervals in Previzion or by hooking up a professional reference monitor to the HDSDI output from the RED directly.  There are two settings in EPIC cameras to watch out for:

  1. Timebase – the internal recording of RED EPIC/SCARLET cameras is set under SETTINGS > PROJECT > TIMEBASE > 25fps or desired frame rate
  2. HDSDI Output – the frequency of the HDSDI output from EPICs can be set independently from the internal recording.  The mismatch is what can cause monitors and Previzion to act up.  Make sure that whatever frame rate your project is set to the HDSDI output matches it.  Under SETTINGS > AUDIO/VIDEO > MONITOR CNTL > HD-SDI> FREQUENCY (BRAIN HDSDI) > 25Hz or corresponding frequency. Verified with RED EPIC X firmware version 3.3.14.

The designation “Brain HD SDI” refers to the left-most mini-SDI port that is next to the HDMI output in the rear of the EPIC.  This is the output that should be going to Previzion.

As long and the HDSDI output frequency matches your project’s frame rate, Previzion is able to read ANC Timecode (build 6903) as well as embed tracking metadata properly.

Older Builds of Previzion (< build 6466) – For older versions of Previzion, a converter must be used to convert the 1080/23.98p signal to 1080/23.98 PsF. The following 2 converters are known to do this: Cobalt Digital 8021,Decimator MD-DUCC.


Genlock and Sync

It is recommended to use an external 1080/23.98p or 1080/25.0p sync generator to directly sync the Red Epic and the Airtrack, instead of deriving sync from the Epic HDSDI output. This is because the HDSDI output can drift, requiring adjusting the tracking delay to keep the foreground and background in sync.

Epic/Scarlet Sensor Size (Mysterium-X)

As of June 2012 firmwares, Red Epics have a “5K HD” mode, along side “5K 16:9” and the “5K” (Full Frame) mode.  Make sure there is no look-around area being sent out the HD-SDI output.  See the notes below for more information.

Here is the calculated sensor widths for all of the Red Epic settings (based on a 5.4 µm, or 0.0054 mm, pixel pitch):


Resolution Description Sensor Width
5120 x 2700 5K FF (Full-Frame) 27.648 mm
4800 x 2700 5K HD 25.920 mm
5120 x 2560 5K 2:1 27.648 mm
5120 x 2160 5K WS (2.37:1) 27.648 mm
3600 x 2700 5K ANA 19.44 mm
4096 x 2160 4K 22.1184 mm
3840 x 2160 4K HD 20.736 mm
4096 x 2048 4K 2:1 22.1184 mm
4096 x 1706 4K WS (2.4:1) 22.1184 mm
3072 x 1620 3K 16.5888 mm
2880 x 1620 3K HD 15.552 mm
3072 x 1536 3K 2:1 16.5888 mm
3072 x 1280 3K WS (2.4:1) 16.5888 mm
2048 x 1080 2K 11.0592 mm
1920 x 1080 2K HD 10.368 mm
2048 x 1024 2K 2:1 11.0592 mm
2048 x 854 2K WS (2.4:1) 11.0592 mm
1280 x 720 1K HD 6.912 mm
1280 x 480 1K WS (2.4:1) 6.912 mm

** Based on 955-0003_v.3, Rev-A1

Epic Focus Magnification

If using the Epic focus magnification to get correct focus while calibrating lenses, be certain to turn it off before starting a lens calibration sequence! Otherwise, you will get incorrect results (a 32mm prime will read as a 85mm focal length.)

RED Epic/Scarlet “HD-SDI Output” with Look-Around

In addition to the above, it is important to check the “HD-SDI Output” before running lens calibrations and comps in Previzion.  As of October 2012, RED Epics have a firmware update that allows for Lookaround that affects Previzion during lens calibration and tracking.

The default setting for “HD-SDI Output” in the new RED cameras is “PROGRAM” output, which provides a clean video feed.  However, this setting can also be set to “MONITOR” output, which provides a slight look around view as well as burn-in Timecode and Title Safe/ Action Safe Frame guides.

Epic Black Bars in Video Signal

Since the Epic sensor is a 1.88:1 sensor, and the live HDSDI output is 1.78:1, there are black bars on the top and bottom of the image. These will create a slightly strange artifact when they intersect with garbage mattes, but will not affect the 5k recorded data.