[FFmpeg-user] 1080i AVC-I 100 frame rate conversion

[Phil Rhodes]

 > I believe that Nicolas is correct, Phil. I know that 24pps cinema is encoded at 24000/1001fps and> therefore running time is extended by about 0.4%.
Lots of cinema stuff is or at least was shot at 23.976, or at least that's the way the frame rate is often labelled in the cameras.
The reason people originally started doing this is that editing was often done on 29.97 video, so there might be audio sync problems if the original material was shot at 24.00.
It's still often done today, at least partly out of force of habit. Sometimes audio timecode is still 29.97 even though the production might never actually see a 29.97 environment unless and until it goes out on TV or on DVD.
I get the impression most of the people behind ffmpeg do not have very much experience in actual film and TV production.
P