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Converting HD 25 fps -> SD NTSC
Have a client who wants to include some HD in an SD/NTSC production. Several clips are HD 1080 at 25 FPS. I’ve downsized 1080i at 30 fps but not 25. No experience at all. Any problems with degradation of image or motion/speed? Any advice on conversion would be welcome.
( Video is 1920×1080 px at 25 fps – from istockvideo )
DD
Dennis Dean
The Dean Group
-It’s about results-
http://www.deangroup.com -
4 Replies
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I believe you’ll have to conform your 25 fps material to 23.98 fps (essentially slowing it 4%). A program like Cinema Tools (included with Final Cut Studio) can do this. NTSC can handle the 23.98 material if you’re going straight to DVD, as the players add the 2:3 pulldown automatically. Placing the 23.98 material in a 29.97 interlaced sequence in Final Cut will also add the pulldown automatically. Of course, you’ll have to lower the resolution to 720×480 with a .9 pixel aspect ratio (DV specs). Since it’s HD, this probably means you’ll need to letterbox, unless you’re working in native 16×9 or something like that. Resolution stays the same but the pixel aspect changes to 1.2. Downsampling and/or letterboxing can be done in Compressor or something similar. Hope this helps.
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Just note, conforming your 25 fps to 23.98 fps is not the same as simply changing the speed in an editor and re-exporting. You need to change the file itself (conform) so that other programs see it as 23.98 and not 25 fps.
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Just wondering if this solution worked for you. Good luck.
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Hi Matt – Yes – brought them directly into the FCP timeline – so far everything seems good. Thank you!
Dennis Dean
The Dean Group
-It’s about results-
http://www.deangroup.com
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