Video Online Vs. Negative Cutting

Picture Cut Accuracy

by Pam Malouf-Cundy

Director to picture editor: "The picture was cut great and I would certainly hire you again, but some of the picture cuts changed when I saw it on the air. On one of our shows, I was shocked to see the dead man's eyes open!"		Shocked picture editor: "What?!? I would never have put that frame in! I am meticulous with all my picture cuts, there's no way!"

Not! If You Are Onlining Beware And Read On...

Let me back up a moment so we're all clear on exactly what I mean by online. Your show shoots on 24 frame per second film (16mm or 35mm), it goes to a telecine bay and gets transferred to 30 fps video masters, and you get a tape copy which is digitized into your Avid or Lightworks. You cut and lock your picture.

At this point, if you are cutting negative, you will make a negative cut list and the final ("air") tape master will be made in a telecine bay directly from your cut negative. However, if you are onlining - you will make a video online list and the final ("air") tape master will be made in a video edit bay from your dailie master tapes - tape to tape.

If you are cutting negative your picture edits will precisely match your cut and digital output. So this doesn't affect you - stop reading right here if you like!

But - if you are onlining - your edits get put out onto a 30 fps list. This list (the numbers that correspond to the master tape daily reels - usually Beta SP or D3) is made up of start and stop numbers based on 30 fps time codes. In other words, the edits we made based on 24 frames per second are all translated to a list based on a 30 frames per second master. At any point, a picture cut in the list can be up to 3 fields (1 & 1/2 frames) off from where you actually intended it to be! (Same overall duration.)

Look at the diagram. You may have cut out on film frame B, but as soon as you printed out an online list (EDL) based on your daily video master, the cut has to occur on a video frame, so part of frame C may be included in your edit in the list!

What! Why, you ask! With a ratio of 24 film frames to 30 video frames, a 6- frame film edit corresponds exactly to a 7Þ frame video edit. But, video edits cannot include partial video frames (less than 2 fields) therefore the corresponding video edit must be either 7 or 8 video frames long. (Remember, with 35mm four-perf picture, each film frame must have its own four perforations per frame and, similarly, each video frame must have its own two fields.) Based on durations and time codes, the digital editing systems add or subtract a video frame to match as closely as possible to the editor's film cut list. Not accurate enough when we know we've made critical picture edits using every last frame of useable footage!

What We Can Do

We can't change this technical fact, but there is something you can do to eliminate the negative effects.

First, know that every picture cut may be changed by 1-2 frames on either side (up to 3 fields).

Secondly, as you make picture cuts throughout your editing - by being aware of this - you can eliminate all bad edits. Don't ever cut right on the last frame of an eye close, blink, light effect or other critical picture edit. (If you must, then carefully check your final online list to see exactly what frame it cuts out on - depending on the result, you could then still fix it.)

Lastly, as a general rule - if you are onlining - always allow 2 frames for the cut to alter. Know that if 2 (up to 3) fields are cut off (exchanged) in the picture list, your cut will still be good. The exact in or out will never be off by more than 2 frames - taking both sides of the cut into consideration.

Please note: If your show shoots on videotape your online will be precisely accurate. This article applies only to shows shot on film which then online.