Matrox Electronic Systems Matrox RT.X2 ユーザーズマニュアル
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Appendix A, Understanding Standard and Advanced Pulldown
The following diagram demonstrates the process:
Advanced 2:3:3:2 pulldown is accomplished by representing the first frame of
progressive video (frame A) as two fields of video (fields a1 and a2), the second
frame (frame B) as three fields of video (fields b1, b2, and b3), the third frame
(frame C) as three fields (fields c1, c2, and c3), and the fourth frame (frame D) as
two fields (fields d1 and d2).
progressive video (frame A) as two fields of video (fields a1 and a2), the second
frame (frame B) as three fields of video (fields b1, b2, and b3), the third frame
(frame C) as three fields (fields c1, c2, and c3), and the fourth frame (frame D) as
two fields (fields d1 and d2).
Performing an advanced reverse pulldown (2:3:3:2 cadence) reverses the process
by converting 29.97 fps interlaced video to 23.98 fps progressive video. This is
achieved by discarding a video frame (two video fields) from the sequence. From
the diagram above, a typical advanced reverse pulldown would discard video
fields b3 and c1. This means that the application can remove video frame C from
the sequence without reading the other frames.
by converting 29.97 fps interlaced video to 23.98 fps progressive video. This is
achieved by discarding a video frame (two video fields) from the sequence. From
the diagram above, a typical advanced reverse pulldown would discard video
fields b3 and c1. This means that the application can remove video frame C from
the sequence without reading the other frames.
When compared to standard reverse pulldown, advanced reverse pulldown results
in less degradation in the converted video because removing an entire frame from
the sequence leaves the remaining frames in the sequence intact, and therefore
preserves the native generation of the video.
in less degradation in the converted video because removing an entire frame from
the sequence leaves the remaining frames in the sequence intact, and therefore
preserves the native generation of the video.
Matrox RT.X2 implementation of advanced
reverse pulldown
reverse pulldown
The advanced reverse pulldown process is simpler than a standard reverse 2:3
pulldown because the additional frame, video frame C in the diagram above, is
tagged when the 23.98 fps progressive footage is recorded to tape. This
information is present in the DV stream and when Matrox RT.X2 performs an
advanced reverse pulldown, it reads this information to identify the additional
frame that is then removed from the sequence. Matrox RT.X2 can perform
advanced reverse pulldown on clips that have been recorded to a DV tape that has
continuous drop-frame or non-drop frame time code.
pulldown because the additional frame, video frame C in the diagram above, is
tagged when the 23.98 fps progressive footage is recorded to tape. This
information is present in the DV stream and when Matrox RT.X2 performs an
advanced reverse pulldown, it reads this information to identify the additional
frame that is then removed from the sequence. Matrox RT.X2 can perform
advanced reverse pulldown on clips that have been recorded to a DV tape that has
continuous drop-frame or non-drop frame time code.
A
B
C
D
a1
a2
b1
b2
b3
d1
c3
c2
c1
d2
Progressive frames @ 23.98 fps
Video fields @ 29.97 fps
Frame A
Frame C
Frame D
Frame B
Frame E