There are many times when it makes more sense to shoot and edit video at 25p than at 24p, regardless of the final framerate(s) to be delivered to various distribution formats, even if you live in an NTSC (or ex-NTSC) country. You may know that “24p” video is almost always really recorded at 23.976p (although Apple and some camera manufacturers often like to round it to “23.98p”). This article is about:
Hello Allan, very interesting and researched article. However it has a few glaring inaccuracies which could be misleading.
1-Cinema Tools or the FCP “Tool>Conform 25 > 24” does NOT conform a 25p clip to 23,976. It conforms it to 24p. Cinema Tools was created to facilitate the transfer of 35mm material in and out of NLE. As such, it enables someone to prepare a clip for a 24fps 35mm telecine. 24p and 23.976 are 2 separate things (which is why HDCAM CineAltas can usually be switched between 24p and 23.98 depending on wether you are shooting a theatrical film or TV broadcast/DVD etc). 24p is used as a 1:1 film workflow framerate. 23.98 is necessary for NTSC broadcast because 24 is not “pullable” mathematically to NTSC 29.97 (A telecine runs at 24/1.001 fps (23.98) so that it can transfer easily to NTSC).
If you convert a clip in Cinema Tool/FCP and open it with QuickTime, you will even see that it’s frame rate is properly shown as 24. If you then convert it to NTSC DVD 23.98 in Compressor and open that .m2v clip in QuickTime you will the frame rate again correctly shown as 23.98.
2- FCP does NOT automatically adjust the audio pitch of a clip after performing a 25>24 conform. After reading your article, I thought the software had been updated without my knowledge and I just tested it again with a 25p/1080p 90 min file in Prores422. The audio is obviously not pitch-adjusted. The female cast members sound like my uncle Joe and the music is atrociously out of key. a AUPitch adjustment is necessary. I have performed this many times and it works flawlessly.
3- It is erroneous to say that film in theaters are projected at 48p and that consists of some sort of alteration (or correction as you put it) over the 24p material. First of all there is no “p” in film. Film is projected at 24fps. You film is shown 1 frame at a time, 24x a second but for 1/48th of a second because the projector’s shutter has to close up while the film is advanced to the next frame. This is not to reduce flicker as you mention but in fact to create it! This stop and go “stroboscopic” effect is what allows film to exist. Persistence of vision allows the last frame of the film to stay in your eye while the film is advanced to the next. Your eye therefore perceives it as a smooth film playback. Otherwise, you would just see a colored blurring racing down the screen!
This is a mechanical device that is necessary for the visualization of a film strip, but your film is shown again at 24fps, 24 frames per second just as your 24p video clip would be shown at 24 frames per second in a video player that does not require persistence of vision for your eye to properly register the information.
Regards
JF Leduc
Posted by .(JavaScript must be enabled to view this email address) on 11/07 at 11:16 AM
JF, I’m very interested in your (2) comment here. I am currently working on a PAL based project - a feature length film sourced on PAL DV. When I read Allan’s article I thought I would be able to get around the pitch correction issue. But as you noted this doesn’t work. My question for you is. What settings are you using with AUPitch. I get phase shifting throughout. There are many paramerters in AUPitch. I just need to adjust the audio back up to the original pitch. So I’ve taken to doing a time stretch in Soundtrack Pro. This works better but not perfect. And it requires quite a few steps. Any recommendations would be most helpful, thanks. pw
Posted by .(JavaScript must be enabled to view this email address) on 11/12 at 08:35 AM
Excellent article. I did use similar methods in some films.
One thing which is really important to mention is artificial light. You may run into trouble with that as there is still 50/60 Hz.
Andreas
Posted by .(JavaScript must be enabled to view this email address) on 12/21 at 12:20 PM
