pulldown.exe question

[scrtagt69]

Just a quick question on this, what does drop frame actually do when you use it? thanks for any insight.

[BJ_M]

don't you mean pulldown ?

drop frame and pulldown are in the glossary

https://www.videohelp.com/glossary

[scrtagt69]

no i meant drop frame..i know what pulldown is. drop frame isnt in the glossary. drop frame is an option in pulldown.exe, i want to know what frame it drops, if it really does drop a frame, just curious to see if i should use that option.

[johns0]

Quote:
In a 30fps Video sequence, a DROP_FRAME time code counts video frames accurately in relationship to real time. DROP_FRAME time code counts each video frame, but, when that .03 finally adds up to a video frame, it skips (or drops) a number. It does not drop a film or video frame, it merely skips a number and continues counting.

This allows it to keep accurate time. So if you're cutting a scene using drop frame time code, and the duration reads as, say, 30 minutes and 0 frames, then you can be assured the duration is really 30 minutes. Confusing? Well, to put it in simple term, DROP_FRAME here is in essence EQUAL a SLOWED_DOWN playback from a pure 30fps into the correct NTSC 29.97fps SPEED. In an MPEG-2 domain, this means that the 00 and 01 frames are dropped or SKIPPED from time code, at the start of each minute except minutes which are even multiples of 10.

[BJ_M]

dont use it -- it doesnt drop a frame in reality ...
Colour video was slowly introduced into broadcast. It was therefore necessary to make it compatible with black and white receivers and to design colour receivers or televisions to be able to receive black and white programming as well. In order to accommodate the extra information needed for colour the b&w’s 30 frame/second rate was slowed to 29.97 f/s for colour. Although usually not an issue for non broadcast applications, in broadcast, the small difference between real time (or the wall clock) and the time registered on the video can be problematic. Over a period of 1 hour (SMPTE) the video will be 3.6 seconds or 108 extra frames longer in relation to the wall clock. To overcome this discrepancy drop frame is used.



Drop frame: Every frame :00 & :01 are dropped for each minute change (60 X 2 = 120) except for minutes with 0’s (00:, 10:, 20:, 30:, 40: & 50 (6 X 2 = 12, 120 - 12 = 108)

[BJ_M]

thanks -- i added it to the glossary now

[BJ_M]

oh -- this is only for NTSC

PAL doesnt have or need this sillyness

[scrtagt69]

thank you both for your responses, this makes perfect sense to me now.

[BJ_M]

when i say don't use it -- i mean in context of mpeg encoding of film based material in which you are applying pulldown ....