4.5

138Compressor User Guide
Use reverse telecine in Compressor
Telecine is the process of converting motion picture film to the NTSC video format used in
broadcast television. The most common telecine approach to converting film’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 fields of one film frame and
then three fields of the next, the 24 frames in 1 second of film end up filling the 30 frames
in 1 second of video.
As shown above, the 3:2 pattern repeats after four film frames.
For editing and effects purposes, it’s often desirable to remove the extra fields and
restore the video to its original 24 fps rate. This process is known as reverse telecine.
An additional benefit 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 file sizes. The reverse telecine feature in Compressor makes it easy to
do this conversion.
When using the reverse telecine feature in Compressor, consider these issues:
• Because of the unpredictable nature of the processing when reversing the telecine,
segmented encoding doesn’t work as efficiently as it does when reverse telecine is
not being used.
• If you pause the transcoding process, the transcode must start from the beginning
when you restart it.