Comments

John_Cline wrote on 7/2/2009, 12:58 AM
Broadcast 1080i is 59.94 interlaced fields per second at a resolution of 1920x1080. 720p is 59.94 full frames per second at 1280x720. (In PAL, the number is 50 instead of 59.94.)

If you deinterlace you material, it will end up at 29.97 frames per second, whether it's 1080 or 720. You will throw away half of your temporal resolution information.

If it was shot 1080i, then keep it upper-field-first interlaced throughout the entire project and render it 1080 interlaced. If it needs to be converted to 720p, then you'll have the 59.94 fields per second which can easily be converted to 59.94 fps progressive.
farss wrote on 7/2/2009, 2:51 AM
It can be either, at 720p can be at 24,30 or 60 fps according to the ATSC or 25 or 50 fps for DVB-T (PAL).

1080 is broadcast interlaced as 50i or 60i however the content may be PsF i.e. frames split into fields. This still looks like 'film'.

Best rule of thumb, stick to however it was shot. Don't mix progressive footage with say interlaced motion graphics . Edit progressive on a progressive T/L and interlaced on an interlaced T/L. If you shoot 24PsF probably best to remove the pulldown and edit on a 24p timeline.

Bob.
MPM wrote on 7/2/2009, 8:33 AM
FWIW, I think in general you don't want to throw anything out if you can help it, for potential re-purposing later on -- IOW when/if possible retain your original content in it's original format. As Bob wrote, you almost always are better off removing pulldown before editing, if for no other reason than it can be difficult to go to the lower fps later on. And, always make sure there's no doubt how the final project needs to be delivered, especially in the US as many stations are to put it mildly, stretching specs a bit.
Laurence wrote on 7/2/2009, 9:36 AM
Show it the way you shoot it. I love 30p and 24p, but only when it's shot that way.