2:3 Pulldown Creation From 24P Video; Figure 1-1: 3:2 Pulldown Creation - evertz 9025TR Series Instruction Manual

Chapter 6 gives a list of the KeyKode emulsion codes supported at the time of writing.
Items of special note are indicated with a double box like this.
1.2.

2:3 PULLDOWN CREATION FROM 24P VIDEO

When an input video feed of 1080p/23.98sF is fed to the either HQ9150 or HD9150 HD Afterburner, the
HD Afterburner inserts extra fields to create a 2:3 pulldown of the picture on the downconverted output
resulting in a 525i/59.94 output. Determination of the output sequence of the fields is determined from a 6
Hz input pulse on the HD Afterburner parallel I/O connector, or from ancillary or LTC time code if it is
present. Figure 1-1 shows the process of creating the 2:3 pulldown from the progressive video input.
A 6 Hz pulse applied to the Parallel I/O connector will normally identify the input frame that will become an
A frame at the output (called the A frame candidate). This 6 Hz pulse must be coincident with the start of
an input frame and can be generated using the Evertz 7700SRG-HD Slave Reference Generator module.
The output of the A frame candidate frame will start four input frames later and will consist of two video
fields.
In the absence of a 6 Hz input, video timecode derived from film ancillary data present on the video input
or LTC on the Video Timecode In connector of the HD9150 can be used to control the pulldown cadence.
Input video frames with frame numbers divisible evenly by 4 will normally identify the input frame that will
become an A frame at the output (the A frame candidate). The output of the A frame candidate frame will
start four input frames later and will consist of two video fields.
The 4 input frame (5 output frame) delay through the HD Afterburner ensures that A frames on the output
are aligned with A frame candidates on the input. The systems designer must take account of this delay
through the HD Afterburner when designing the audio path. This delay may be accomplished using an
Evertz 7740DLY-AES4 Quad AES Delay module.
calibrating the edit timing for the Standard definition VTR.
6 Hz cycle
0
1080p/23.98sF
A Frame Candidate
0 0
Frame
Buffer
odd even
525i/59.94
OVERVIEW
1 2
1 1 2 2
odd even odd even

Figure 1-1: 3:2 Pulldown Creation

9025TR Series Film Footage Encoders Manual
This delay must also be compensated for when
3 4
A Frame Candidate
3 3 4 4
odd even odd even
0 0 1
odd even odd
A Frame
Revision 1.3
1 1 2 2 3
even odd even odd even
B Frame C Frame
3 3
odd even
D Frame
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