720p60 3:2 Pulldown to 720p24 in Final Cut
by Brad Weston
on
Feb 3, 2008 at 12:39:29 am
We shot a feature film with a Panasonic Varicam at 24p and captured directly to a computer via HD-SDI through a BlackMagic Design Decklink HD Extreme using Apple's ProRes codec (looks fantastic by the way... for those interested there is definitely a visual difference between DVCProHD and ProRes when capturing from an uncompressed source). The transport mechanism was 720p60 because that's what the Varicam outputs, and Final Cut's capture doesn't pay any attention to the HD-SDI meta-data (if any exists) so the pulldown frames were not removed in the capture process.
So, now I have all of this 60p footage that has superfluous frames added in the 3:2 pulldown process of the camera. When we edit these clips within Final Cut in a 24fps timeline, about a fifth of our clips play back stuttered as they are dropping, or more accurately doubling, every other frame and ignoring those in-between. I've figured out the reason for this is because Final Cut has no clue what frame of the 3:2 sequence each clip begins with and thus thinks each clip begins on an A1 frame. In 4 out of 5 frame sequences, this is fine, as shown here:
Normal telecine sequence:
AAA BB CCC DD EEE FF…
Edit starts on first frame:
AAABBCCCDDEEEFF
ABCDEF
Edit starts on second frame:
AABBCCCDDEEEFF ABCDEF
Edit starts on third frame:
ABBCCCDDEEEFF
ACCEE
Edit starts on fourth frame:
BBCCCDDEEEFFG
BCDEFG
Edit starts on fifth frame:
BCCCDDEEEFFGGG BCDEFG
As such, we see a stuttering issue (which appears as 12fps... every other frame is ignored of the original footage) on all clips that begin with the 3rd A-frame because Final Cut reverses this pulldown automatically but assumes that the beginning of the clip is at the beginning of the sequence every time, when it's not. I had hoped that I could somehow change the starting pulldown frame within Final Cut but see no way to do this. Cinema Tools doesn't have any good tools for working with 60p original content, so I'm stuck here.
I downloaded and installed the Nattress Standards Conversion filters and have experimented with them but have not been successful at eradicating this problem entirely. It seems its conversion from 60p to 24p assumes 60 unique frames, not a 3:2 pulldown clip. This coupled with the fact that Final Cut has some flakiness with its handling of the pulldown in general leaves me seeking the best strategy for handling this from wise council, which I would absolutely this forum to be.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 3, 2008 at 2:22:27 am
Hmm. Don't know about Blackmagic cards, but with Kona cards, you can capture varicam footage to whatever codec you want and remove the pulldown on the fly (just use a preset with the word Varicam, a frame rate of 23.98 and whatever codec you want to capture in it). You will kill yourself trying to remove all this pulldown. Get yourself a Kona card and recapture. Final Cut CAN remove the pulldown from varicam footage, but you would have had to have captured in DVCPro HD.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Brad Weston on Feb 3, 2008 at 2:54:30 am
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.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 3, 2008 at 3:05:54 am
[Brad Weston]"We have DVCProHD on tape, but we don't want to recapture from tape at a lower quality. "
Sorry. I am at a loss except if you manually delete frames. I would recapture especially if you need it for film out. Email Nattress, perhaps he can help you out with his plug in.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Matthew Nelson on Feb 3, 2008 at 6:05:48 am
To jump in here Blackmagic is about a generation or two behind Kona on a couple of things this being one of them. However the decklink does pass through the RP188 data so you can use the DVCPro HD frame converter tool found in tools menu. But I don't know if using the ProRes setup will screw this up.
[Brad Weston]"using Apple's ProRes codec (looks fantastic by the way... for those interested there is definitely a visual difference between DVCProHD and ProRes when capturing from an uncompressed source)"
This I'm not getting. Your source is compressed. You are capturing from DVCPro HD tape recorded in the DVCPro HD codec. You are not going to get any better then that even if you capture in 10bit 4:4:4 uncompressed. Your source is your ceiling.
I would try the frame converter tool. If that's a no go. You'd be better off recapturing using the Blackmagic 720P 59.94 DVCPro HD easy setup then pulling the duplicate frames in all your footage. I assume color correction is planned for your project and if you use Color you can render out of Color in ProRes HQ if that's what you want as your final. Just note if you lay this back to DVCPro HD tape it will be recorded in that codec.
If pulling frames is really more of an option then recapture I'd look into renting a Snell & Wilcox Ukon. Which can correct broken cadences.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Brad Weston on Feb 3, 2008 at 1:23:29 pm
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 :-) )
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Mike Most on Feb 3, 2008 at 3:49:08 pm
Your mistake was in not investigating what it would take to maintain the cadence information in the original recording. You can record uncompressed in 720p/60 from a Varicam, but you have to record the entire vertical interval and maintain the VITC user bits when you do it. This is what the Varicam uses for its "frame flags" that allow automated recovery of the original 24 frames in post. Without it, you're forced to figure it out on a clip by clip basis. If you were compressing to ProRes "on the fly," then you were recording with a Mac based device by definition. If you were doing that, you had some type of capture card in the loop, and if THAT were the case, you should have been able to remove the pulldown frames as you were recording. That would have been a much better approach, as among other things, it would have required less storage.
There are far too many formats out there today, and there are far too many pitfalls in each one. When you decide to kludge a new approach, you need to do your homework - ahead of time - if you want to be able to post it efficiently and accurately.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Brad Weston on Feb 3, 2008 at 4:06:49 pm
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?
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Matthew Nelson on Feb 3, 2008 at 4:17:52 pm
The last resort before the DVCPro tapes most likely is the S&W Ukon, but I'd call a dubb house or post facility to run a test. The Ukon may not help since the VITC has been divorced from the Varicam source.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 3, 2008 at 5:14:42 pm
Sorry if I wasn't clear enough before, Brad.
the tool is you, clip by clip frame by frame. Load a clip in the timeline take the first frame of each 3:2 sequence and delete the duplicate frame(s) after it. When you have done that you will be left with 24 discrete frames. Remember how I said I would rather eat glass than do this? I wasn't kidding.
Save yourself the trouble and recapture from your backup. At least you had a backup in place. You can capture your source tapes to ProResHQ @ 24p. This will help in a film out anyway as all timecodes and cut lists can be tracked.
Or as had been mentioned, you might be able to run all of your footage through an external box such a Ukon, Terranex, Alchemist or whatever, but at that point it's going to get transcoded anyway and cost you boat loads of dough, so you might as well recapture from your source tapes and squeeze every ounce of quality you can from that.
I KNOW it's not the answer you want to hear, I know. But recapturing from your source tapes will save you the most time, money and hair on your head in the long run.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by John Kaley on Feb 3, 2008 at 7:54:45 pm
I've used Cinema Tools to do this. Open a clip in Cinema Tools that you want to remove the pulldown from. Click the "reverse telecine" button at the bottom of the clip. These are the setting I've used, but you may have to tweek them based on your clips.
Capture Mode: Field 1 only
Fields: Style1 A
Frames Conform to 23.976 do not check "Standard upper/lower"
File: New or same, depending on if you want your files overwritten or not.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by John Kaley on Feb 4, 2008 at 4:37:46 am
I did a test on 720p60 footage and it works fine. My settings were:
Capture mode: Field1-Field2
Fields: Style1 AA
Frames: Conform to 23.976 with the "Standard Upper/Lower" box checked
File: Create New
You'll need to tell Cinema Tools where your A frame is. My clip was WWSSW which makes the A frame on timecode numbers 0 and 5. (This is the AA thing in the settings above) Select BB or BC....etc based on which timecode frame you footage starts on.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 4, 2008 at 6:44:47 pm
John, how are you getting this to work? I have 720p60 footage here in three different codecs and reverse telecine is grayed out for each one. I am happy to totally correct any wrong methods that I might have said in this thread. As far as I know, Cinema Tools rev telecine only works on 60i footage.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by John Kaley on Feb 4, 2008 at 10:00:25 pm
Hello Jeremy. I assumed the footage was 60i because he said is was shot 24p and has 3:2 pulldown in it. That doesn't seem to be the case here. You are correct that Cinema Tools needs 60i source footage to work. I'm not familiar with 60p footage that has 3:2 pulldown it in. How's that possible?
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 4, 2008 at 10:25:33 pm
[John Kaley]"I'm not familiar with 60p footage that has 3:2 pulldown it in. How's that possible? "
Well, we are heading off topic here, but 720p60 is 60 discreet progressive frames per second. If you have 720p24 then you simply add 3:2 pulldown to get you up to 60. Instead of the pattern going in fields (3 fields then 2 fields) it goes in whole frames. 3 duplicate FRAMES then two duplicate frames. 3:2 pulldown. Then you go from 720p24 to 720p60. The 'active' and duplicate frames get flagged as an active or duplicate frame upon being recorded to the DVCPro HD data stream. When capturing, Final Cut can then capture just the active frames and skip the duplicates based on their flagged information leaving you with 23.98 media. It's a very very cool system.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Sean ONeil on Feb 4, 2008 at 5:05:15 am
My first Varicam project I made the same mistake of cutting in 60p instead of 24p.
The key is to recapture in 24p. Create a new 23.98 Varicam sequence. Then copy and paste your clips into this new sequence and then make the media offline. Then recapture using 23.98 Varicam settings. The way it works is confusing. The deck plays back at 60p, but Final Cut removes the redundant frames during capture.
I used Firewire from a AJ-1200A deck. But I believe a BMD card has Varicam settings so it can do the same thing.
Because you cut in 60p, your sequence will have bad 3:2 cadence. So when you recapture/rebuild in 24p, you'll have to manually close up a 1-frame gap in between occasional edit points. Other than that, it will all come in perfectly. It's by far your best solution.
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Brad Weston on Feb 5, 2008 at 10:50:08 pm
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.)
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 6, 2008 at 3:49:23 am
Image quality is one thing, ProRes should handle multiple generations without much trouble which you have found out. It's the cadence that's really the issue. Are you saying that you have no more duplicate frames? Why'd you delete the first frame? Just curious...
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Brad Weston on Feb 6, 2008 at 5:34:43 am
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).
Re: 720p60 3:2 Pulldown to 720p24 in Final Cut by Jeremy Garchow on Feb 6, 2008 at 4:07:34 pm
I see what you are doing now, you are trying to get FCP or compressor to just drop the pulldown frames. Instead of COmpressor, why can't you just edit the clips in question one frame later?
I don't really see a problem with this, it's just that I have never tested it. If you can go through each converted clip frame by frame for a couple of seconds and not see a single dupe frame, you are golden.
