Wednesday, February 06, 2008

Do non-integer frame-rates confuse you?

It's something that people ask me about all the time - 23.976fps seems particularly perplexing. It all related back to NTSC being 59.94 fields and the need to transfer film (and now HD 'electronic film') back to 29.97fps (the 3:2 pulldown equates 29.97 to 23.976). So why didn't they stay with 60 fields when NTSC came in? Apparently it is all down to someone at the SMPTE thinking that the cross-talk between colour sub-carrier and the audio carrier causing in-vision intereference. Subsequent experimentation showed that this wasn't the case but by that point in 1956 29.97fps and hence drop-frame timecode (and the four-field sequence) were with us.
Anyhow - the most coherent explanation of all this and how it relates to HD frame rates can be heard in this week's Schubin Report.

No comments: