Inverse Telecline

[ToiletDuck]

Can any of you tell me what this is?

[jggimi]

Sure.

FILM = 35mm, sprocket holes, 24 frames per second.

To transfer from film to video, the frame rate must change:

NTSC = National Television Systems Committee = 29.97 frames per second
PAL = Phase Alternation Line = 25 frames per second

To convert to PAL, most film is just sped up to 25 fps, and the audio is then adjusted.

To convert to NTSC, a process called Telecining is used. First, the film is slowed down to 23.976 frames per second. Then, six extra frames are added every second. The extra frames are made by combining fields -- half frames, made up of the odd or even lines -- of adjacent frames. These two half frames are interlaced together.

If you were to examine, frame by frame, a scene with movement out of an NTSC video transfer from film, you will see completely perfect frames next to frames that appear to be interlaced. These interlaced looking frames were added by the Telecining process.

Inverse Telecining is the process of removing those extra frames, resulting in a video with a framerate of 23.976 fps.

If you click on http://www.doom9.org/ivtc-tut.htm you will get lots of advice on when to use Inverse Telecining, and when not to.