4.1.2

Table Of Contents

Chapter 5 Advanced tasks 72

About reverse telecine

Telecine is the process of converting motion picture lm to the NTSC video format used in

broadcast television. The most common telecine approach to converting lm’s standard 24 fps

frame rate to NTSC video’s 29.97 fps frame rate is to perform a 3:2 pulldown (also known as a

2:3:2:3 pulldown). If you alternate recording two elds of one lm frame and then three elds of

the next, the 24 frames in 1 second of lm end up lling the 30 frames in 1 second of video.

3:2 Pull-Down

Before (23.98 fps)

One second

A B C D

A A B B B C C D D D

Field

A B C D A D A B C D A B C D A B C D A B C D

B C

BA B B CC D DA A B B B C C D D D A A B B B C C D D D A A B B C C D D D A A B BB CC D D D A BA B B CC D DB

After (29.97 fps)

As shown above, the 3:2 pattern repeats after four lm frames.

For editing and eects purposes, it’s often desirable to remove the extra elds and restore the

video to its original 24 fps rate. This process is known as reverse telecine. An additional benet of

restoring the original is that it’s easier to convert this to PAL, the European broadcast standard,

which uses a 25 fps frame rate.

The lower frame rate also has the advantage of requiring fewer frames per second of video,

leading to smaller le sizes. The reverse telecine feature in Compressor makes it easy to do

this conversion.

3:2 Pull-Down Removal

One second

After (23.98 fps)

Before (29.97 fps)

BA B B CC D DA A B B B C C D D D A A B B B C C D D D A A B B C C D D D A A B BB CC D D D A BA B B CC D DB A

A B C D A D A B C D A B C D A B C D A B C D

B C

A A B B B C C D D D

Field

A B C D

67% resize factor