[Brad Weston]

Well, by deleting the first frame of the source 60p content for those roughly 20% of clips that have frame doubling, it changes the starting point of the 3:2 cadence and fixes the problem. As the “frame” that is deleted is duplicated on frame 2, you’re not really losing anything, so far as I can tell.

So, I’ve tested it, and it appears that all is well with this method… what’s more, clips are now 2/5 the size they used to be, which is great. If clips are 24 frames, look good, and fit the timelines, do you see any other pitfalls that I’m missing (an answer of no at this point would be of great relief, for what it’s worth).

[Brad Weston]

Okay, so I have a solution and I want to run it by folks here to get their opinions on it. Please do so based on the facts that I tell you here because it goes counter to what you may think in your head.

I did a test and ran some source 60p clips that were part of an edited sequence through Compressor at 24p (source material was ProRes HQ, output is ProRes HQ). The net results on a clip-by-clip basis show ZERO difference in a Final Cut Pro timeline. Let me reiterate this. the “recompressed” 24 fps “recompressed” clip looks IDENTICAL to the 60fps original clip. A blind A/B comparison had no less than 6 people not able to tell a difference, or even that the switch had been made.

So, in “recompressing” the clips (from an uncompressed ProRes quality to an uncompressed quality ProRes movie), about a fifth of the output clips have frame doubling because of the cadence issues that have been seen throughout this thread. I just opened up these problem 60p source clips, deleted the first frame, “recompressed” them to 24p, and voila… they play fine.

I “relinked” the source clips of my timeline to these new 24p clips and there were a couple quick black flashes… easy to correct.

Again, and I can’t emphasize this enough because the word “recompress” inherently means “degrade quality” under normal circumstances, but there is ZERO noticable difference between the clips. Any objections that should be made to this should address technical problems that are not related to image quality.

(For those who have not read the full thread, the source content was recorded live from the camera via uncompressed HD-SDI on set to the computer and compressed with ProRes. All clips were compressed directly from uncompressed footage, not from DVCProHD. We have DVCProHD backups on tape, but would prefer to not have to use it.)

Thanks!

bRaD

[Brad Weston]

Believe me, I’m well aware of my mistake in not working through this ahead of time, but that doesn’t help me now. We began this process with a plan to use the AJA IoHD, but it didn’t ship in time so we had to quickly find a different solution.

I am happy to “figure it out” on a clip by clip basis if there was a tool that would allow me to remove the extra ProRes frames, but I don’t know of such a tool. In Final Cut, the DVCProHD Frame Rate Converter does not pay any attention to the ProRes Clips. Is anyone aware of a tool that will allow me to do this?

[Brad Weston]

Thanks for the reply, Matt.

I think you misunderstand… on the set we had an HD-SDI line running right from the camera to a capture machine so we were capturing via HD-SDI an UNCOMPRESSED stream, that was then compressed on the fly using ProRes 422… none of the footage we have has ever been compressed with DVCProHD. The reason for this is because there was a noticable difference in our blind tests between footage that was captured originally using DVCProHD and that using ProRes422. We recorded to tape simultaneously using DVCProHD to use as a backup, but Lord willing that won’t be necessary.

Our last project was captured and edited entirely in DVCProHD and we did some tests ingesting directly to ProRes and avoided some of the visual problems we saw with DVCProHD (and in the process created this unexpected new one).

The method you mention is what I was hoping for, but the DVCProHD Pulldown function of Final Cut only works with DVCProHD content. When I select it in Final Cut I get the message “No Video Found” or somesuch. We are editing the film entirely on the 59.94 timeline and at some point will just copy the entire set of footage into a 23.98 timeline and allow Final Cut to remove the frames. I’ve done this as a test and as I said, about 20% of the clips begin with the third frame and as such this would require that we go back to the 60p timeline and edit that clip, copy it, and bring it back into the 24p timeline. The clip editor of any clip in a 24fps sequence just shows the downconversion so you can’t set this within the clip editor directly (I call this an opportunity for development 🙂 )

In any case, thanks for your help.

bRaD

[Brad Weston]

Okay… HOW would I delete individual frames?

Already had the dialog with Nattress… no help unfortunately.

Still hoping for, playing around with, and researching a simpler way… but thanks!

[Brad Weston]

We can’t recapture… what we have is what we have, for better or worse. We have DVCProHD on tape, but we don’t want to recapture from tape at a lower quality.

So, maybe I’ll kill myself, but I’d like to know exactly how I would go about fixing the problem. At present, I don’t really know.

We are editing in a 60fps timeline at present and it looks great, but for the filmout we’ll have to go to 24fps native. As I stated, about a fifth of the clips have the problem so the present plan of action is to identify these clips, change the in-point on the problem clips in the 60fps timeline, then bring them back into the 24fps timeline. My initial tests at this have not worked as planned however.

Any pointers, easy or hard, would be most welcomed.