120 fps timecode runs at a 4x rate

[Jacob Owen]

When jam synching external timing (time of day) on a 120 fps varispeed project with a 30 fps project base, I'm finding on playback that the timecode runs at the rate of playback, not at the rate of recording -- what took a half-second to record looks like it took 2 seconds according to the playback overlay.

I'd like to display a real-time timecode overlay on slow-motion video, ie. the timecode would run slow as well, showing actual time during recording in hours:minutes:seconds:milliseconds.

Any thoughts?

I'm using Adobe CS4 & REDCine on a PC-platform.

[Stuart English]

If you mapped the actual time of day external timecode to the 120 fps recording, then you would see 4 frames with identical timecode, and that is usually very bad. So that's why the camera uses a sequential timecode count from the first frame of the clip - which irrespective of capture frame rate - matches to the actual time of day.

Second issue is even if the camera did what you suggest, your post app may also only look for the first frame of timecode and calculate the rest ..

... sounds like you want to read the frame timestamp instead ?

[Jacob Owen]

The Premiere CS4 timecode overlay (in the Effects panel) lets you interpret the timecode framerate without affecting the project framerate, but only up to 60fps, so I can get the overlay to slow down to 2x speed, but not to actual 1x.

Somewhere I need to tell the camera or the post software to interpret timecode at 120 fps, while maintaining the slow-motion project rate of 30 fps.

I hope we're not running into a limitation of SMPTE timecode?...

[Joe G.]

Time is relative. -Einstein
:)

[Cail Young]

I hope we're not running into a limitation of SMPTE timecode?...

Yes, you are. 60P timecode is really just using the field flag to denote every other frame in a 30fps TC stream.

You'll need to use frame counts, I'm afraid.