Reverse Telecine

[Jeremy Garchow]

You can digitize into the io removing 3:2 pulldown if you use a 23.98 NTSC setup. The trick is, is that you have to make sure when you log the clips, the in point starts on an A frame (usually frame :00). Give it a shot, it works really well. If you are having trouble, call AJA and they can help you out.

Jeremy

[Kevin Hedin]

[JeremyG] “The trick is, is that you have to make sure when you log the clips, the in point starts on an A frame (usually frame :00)”

Actually, it can be a frame that ends in :00 or 05. But since this could slow your logging process, just log as normal, then before capturing, change the MEDIA START TC in the Browser for each clip. I just change it to the nearest A frame (or :00, 05).

[Michael Lazar]

Can’t the first A frame really fall anywhere? I’ve worked with telecine’d film supplied by clients where I was doing the IVT back to 24P when I transfered it from tape to QT. It was quickly apparent that the pulldown cadence didn’t always start on frame :00 and that I had to manually determine the cadence (which was invariant) before each transfer. (Note: the Decklink card I was using to perform the IVT allows you to set the A frame to whatever ever value you wanted.)

Possibly this was the result of a sloppy transfer. What’s the skinny?

Michael Lazar

[Kevin Hedin]

To me it sounds like either the result of a sloppy film transfer, or latency in your capture hardware that would result in inconsistant A frames.

It is my understanding, and my experience that frames :00 and :05 are the STANDARD ‘A’ frames whether shot on 24p Video cameras, or film transffered to video. It is a standard that I have come to rely for the last 7+ years. Without this standard, I would not be able to predict my pulldown pattern and would have to guess each time. And guessing is not very professional.

I HAVE run across footage with incorrect pulldown cadences, but they were either faulty clones from the original, or previously edited material, but usually rare cases in which I could deal with.

[Jeff Gural]

So then is it a crap shoot type thing if the 00 or 05 frames aren’t A frames? Do you just try capturing with 01, 02, 03,04 and see which one works or are there more possibilities than that. I tried removing the telecine in Cinema Tools and there were so many choices of patterns, etc. and couldn’t find a combo that worked. (why is it that After Effects can determine the pattern and Cinema Tools cannot?)

Thanks,

Jeff

[Michael Lazar]

With the material in question, this is in fact what I did – making a short test capture until I got all P frames. Then I knew I was good cause the cadence was completely consistent – only the location of the A frame was random.

You can also eye-ball the thing on a progressive display, counting jitter frames and looking for the cadence. You need a well lit section with lots of motion to do this.

Michael

[Kevin Hedin]

[jeff Gural] “So then is it a crap shoot type thing if the 00 or 05 frames aren’t A frames? Do you just try capturing with 01, 02, 03,04 and see which one works or are there more possibilities than that.”

It’s a crap shoot if you are working with a previously edited tape, as the cadence will differ on EVERY shot. If you are working with a Film to Tape transfer, and someone f***ed up the cadence, then it should be off by the same amount throughout the whole tape, in theory.

If you find yourself guessing the A frame, and your deck doesn’t show whole frames (as BetaSP does not), just capture a section in 29.97 (with movement in the scene), and analyze the footage in your NLE to find the A frame. Then log all your footage with the A frame as the MEDIA START point, before you capture at 23.98. Remember, the A frame is the frame with a progressive frame before and after it.

As far as AE goes, well it’s just smart I guess. I don’t know why Cinema Tools can’t do the same. Cinema Tools assumes that frame that is currently being displayed is the A frame, so if your preview window is not parked on an A frame, no combination of settings will work to reverse the pulldown.

[Jeff Gural]

Thanks for all the great info. everyone. I’ll give this a shot. I tend to edit a lot of content that originates on film and I’ve wanted to keep it in the 24 fps realm. I was also told by the transfer house that they will force an A frame on 00 or 05 as you suggested, but only on request.

Thanks again,

Jeff