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What rate timeline for DVCPRO HD (720p60) clips?Posted by LizF
I have footage shot 720p24 on the Panasonic HDX900 and recorded by the camera on DVCPRO HD tape at 59.94 with a regular--not advanced--pulldown (meaning there are repeated frames in a 2,3 pattern). The footage was captured into FCP 7.0 by firewire as DVCPRO HD (720p60).
The short videos that I am editing will be (1) put on a university's YouTube channel and (2) played out from either a quicktime or a DVD onto a high definition flat screen in a museum. (They will NOT be transfered to film or broadcast on television.) My question is: when I make my first sequence in Final Cut should I go to Easy Setup and set the rate of the sequence to 29.97 fps, the format to Offline RT, and Use to Offline RT HD - 29.97 and then work with my 59.94 clips at the 29.97 rate of the sequence. This was suggested to me, and I don't understand why. Or should I edit my 59.94 clips in a 59.94 sequence? Or do something else? Thank you for your help! I am very confused about this. Liz
Why offline- just edit DVCPROHD.
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First of all, 59.94 and 29.97 are effectively interchangeable. You'll find that whether people say one or the other varies from facility to facility. Final Cut Pro and, I think, Avid use the nomenclature "29.97" to refer to the interlaced NTSC frame rate, while other systems (and most tri-level sync generators that I've seen) use "59.94," but they mean the same thing: 60i.
Second, 3:2 pulldown is not inherently a bad thing. The idea of editing video at 23.976 is a fairly new one, relatively speaking. Before 24p editing, everybody cut stuff that originated on film as telecine transfers with 3:2 pulldown inserted. There are a few things you need to be aware of: cutting from a jitter frame to black, or from black to a jitter frame, can produce unpleasant results, and so can cutting from a jitter frame on one shot to a jitter frame on another. But really, cutting footage with 3:2 in it is no big shakes. You can remove the pulldown ? although I've ranted before about Final Cut's infuriating inability to do it easily ? but you don't have to. Now, that said, since you're going out to the Web with this, there are some good reasons to remove the pulldown and cut in a 24p timeline, outputting a 24p master for further encoding. We use 3:2 pulldown because it works on television, but computer screens are not televisions. You can go out for computer delivery at 60i ? either real 60i, or 24p with 3:2 ? but it's not a total no-brainer like it is when you're editing for broadcast. So really, it's dealer's choice here. If Final Cut had an easy, reliable way to remove the 3:2 ? like, y'know, every finishing system on the planet ? then I'd say sure, yank that pulldown out and cut at 24p for 24p delivery. But as it is, that would be extra up-front time, and probably some trial-and-error depending on what tools you have at your disposal, and it just might not be worth it for you in this case. ![]()
Yes, you don't remove offline DvcproHD. It's already an offline format (for film, etc..). Drives are relatively cheap, c'mon.
Hmm... I'm not in NTSC land, but to remove pulldown, can't you send it to Cinema Tools (or compressor)? Or do you have to break them up into individual shots first? ![]() www.strypesinpost.com
I was told by Panasonic that the HDX900 records 60 p, not i. Jeff, does that make a difference since you refer to 60i? When I step through the footage frame by frame, I do not see any interlaced frames. Does that mean there are no jitter frames to worry about?
Someone who runs a post facility has urged me to recapture at 24. He said: "If you shot at 24, you should be posting at 24. Every single shot has a cadence of 3-2. The cadence is constantly changing if you are not always cutting on an A frame. If you edit at 24 and make a new master at 30, the cadence would all be the same." How would I know an A frame when I saw it? He also said if I throw out frames that are repetitive and capture only the real individual frames, I get a lower data rate and higher picture rate. I am ready to go if editing the 60 footage that we already captured will work well on YouTube which requests 30fps and when shown on an HD flatscreen in a museum. Otherwise, I need to think about recapturing 20 hours. The cameraman who shot the footage with the HDX900 said: "There's nothing wrong with having a pulldown. A pulldown is exactly what a camera does to render 24p images to look right in a regular old 59.94 timeline. That's its entire job. It's the solution not the problem. I don't understand why someone would suggest removing the pulldown, extracting the 24 frames, putting those frames in a 24fps timeline, editing, and then after editing adding a pulldown back into it. If you're not going to film, removing and then adding back in a pulldown is just adding a completely unnecessary step that's even going to make your footage look worse. It's a bit like saying that you are doing a science problem in which you have metric data, and you need to write a report in which you present metric data, but for some reason they want you to convert all your information from centimeters and liters into inches and gallons, do your math, and then convert your results all back to centimeters and liters only at the end. Doesn't make sense." Thank you for helping me sort through the conflicting responses. Meg
>I was told by Panasonic that the HDX900 records 60 p, not i. Jeff, does that make a difference
>since you refer to 60i? Okay, I missed this one. 720p by broadcast standards refers to 50 or 60 progressive frames (depending on whether you exist in PAL or NTSC worlds). I think Jeff was talking about 1080 frame rates. Here, things are a jungle of numbers. In the 1080 world, you have 1080i25 which is also referred to as 1080i50 (depending on the software you use). Then there is 1080i29.97, which is the same as 1080i59.94 (and sometimes 1080i60). Basically, you never have 60 frames per second on interlaced (you'll get 120 fields a second). Doesn't exist as a broadcast standard. You should be able to remove the pulldown on capture, as the pulldown is full frames, not interlaced. But you may need an AJA card to do this. ![]() www.strypesinpost.com
Wow, much to cover here.
First of all, I took you at your word when you said your footage had 3:2 pulldown in it. If that's not the case, then obviously none of my advice applies. I can't see your footage, so I don't know how it was recorded. So for the purposes of this thread, I'm gonna assume it really does have 3:2. Second, that camera can shoot in a variety of formats. It's untrue to say that it "records 60 p, not i." Since I can't see your footage, I have no idea what you've really got there. The two people you quoted are ? and boy, does this suck ? both right, more or less. It is possible, as I said, to remove the pulldown and cut at 23.976. There are some (minor) advantages to this. There are also some disadvantages, principle among them the fact that Final Cut offers no easy, fast and foolproof way to remove 3:2. It should. But it doesn't, and we just have to live with that fact. So you can remove the pulldown, or you can leave it back in, and in the absence of a clear delivery spec, deciding which to do is more a matter of workflow details and personal preference than anything else. This part, however, is flat-out wrong: "removing and then adding back in a pulldown is just adding a completely unnecessary step that's even going to make your footage look worse." That's completely untrue. The awesome thing about 3:2, and the reason why it's so clever, is that it's completely lossless. All you're doing is rearranging the order in which fields appear. You're not actually changing those fields at all. That's also, incidentally, why practically every system other than Final Cut can add or remove 3:2 in real time or faster: because there's no math involved at all. Now, if your workflow is in some other way boned ? say, you're cutting in a heavily compressed format ? then the process of rearranging those fields and then recompressing the resulting frames can degrade your footage. But as long as you're working in a good intermediate format, you won't suffer any more by removing or adding pulldown than you would by doing a deck-to-deck dub from one Digibeta tape to another. That is, you won't be able to see the difference. Oh, and as for cadence. This comes down to editor's preference. Some people I've known have been total nazis for only cutting on the AA frame. Others don't care, as long as they're not cutting on a jitter frame. Myself, when I cut 3:2 stuff, I prefer to cut on the AA frame, but I don't fling myself from the parapets if a BB or DD frame works better. (Brief 3:2 tutorial: the cadence goes AA BB BC CD DD. The frames referred to as "AA," "BB" and "DD" are whole frames, while the "BC" and "CD" frames are made up of fields from two different frames. When you pause playback on a "BC" or "CD" frame, your monitor appears to "jitter," 'cause it's displaying fields from two different frames. That's why they're called jitter frames.) As for identifying an AA frame, it's the frame that's one frame away from a jitter frame. If you're stepping through your footage and it goes: J S S S J J S (where "J" means you're looking at a jitter frame and "S" means a steady frame), then the third frame is your AA frame. In that example, you're looking at CD DD AA BB BC CD DD. As long as the cadence is unbroken, the AA frame is always the second frame after a jitter frame. ![]()
Thank you for the explanation of AA frames and jitter frames, which is very helpful.
When I step through my footage frame by frame, I see the same frame twice and then the next frame three times and then the next frame twice and so on. All the frames look complete and clear. There does not seem to be a jitter frame. What kind of pulldown is that called? Is that kind of pulldown easy to edit with in 59.94? (Panasonic techs looked at our tapes in their decks and said there is regular pulldown.) Should I have my tapes recaptured with a kona card or something other than FCP to take out those duplicate frames in a reliable manner? The main distribution outlet for our videos will be the web and people will be watching from their computers. As you know, I am trying to figure out whether it is better to edit the DVCPRO HD footage I have already captured at 59.94 or start over and recapture tapes at 24. Thank you!
>>Second, that camera can shoot in a variety of formats. It's untrue to say that it "records 60 p, not i." Since I can't see your footage, I have no idea what you've really got there.<<
In response to Jeff's statement above, I spoke with Panasonic pro technical support on the phone and then in person, and they are all adamant when they say the Panasonic HDX900 does not shoot 720/60 i.
>Should I have my tapes recaptured with a kona card or something other than FCP to take out
>those duplicate frames in a reliable manner? That's my guess. Wild as it seems, I don't work with pulldown in PAL land. But Shane I gather works with this format quite regularly. And he should should chip in, if not, PM him. Regarding pulldowns. You have 2 kinds of pulldowns- 2:3 (regular) pulldown and 3:2 (advanced) pulldown. Regular pulldown is what you see when you telecine a film for broadcast. It is the smoothest pulldown out there, but removing it isn't as simple, as it requires 1 frame to be rendered (at least in a traditional interlaced medium). Advanced pulldown, is designed for easy removal. At one time, you can't shoot 24 FPS, unless you make it 29.97, and you get rid of it later in post (in a way you are tricking the camera and tape into thinking that it's really getting 29.97). You can't have 720 HD as an interlaced format. The EBU was pushing for 720p as the broadcast standard, because at this frame size, they can broadcast 50 or 60 full frames a second, instead of interlaced fields. Hence 720 is a progressive only format. It is important, because most HD displays in use is progressive. I would think 720p24 repeats frames, and not fields, unlike traditional telecine. Any way you can upload a second of it? ![]() www.strypesinpost.com
Itty-bitty nitpick: the terms "2:3" and "3:2" are interchangeable; both refer to a pulldown pattern that looks like this: AA BB BC CD DD What they call "advanced" pulldown (stupid marketing names) is properly called 2:3:3:2, and it looks like this: AA BB BC CC DD In the first case, you have two fields from frame A, three from frame B, two from frame C and three from frame D. Hence the "formal" name for that pulldown pattern, which is 2:3:2:3, abbreviated either to 2:3 or 3:2, confusingly. In the second case, it's two fields, three fields, three fields, two fields. This has the advantage of letting the computer just drop the third frame of every quintet. But it has the disadvantage of totally effing up your motion cadence. Having just that one jitter frame in the middle of each five frames makes the footage look jerky, like it skips a few times every second. So 2:3:3:2 is only suitable for later pulldown removal; you can't get away with playing it on a monitor like you can with 3:2. If you want to get even deeper into the theory of pulldown, reflect on this: The frame rate of film is universally 24 frames per second. The frame rate of NTSC television is 60 fields per second (we're rounding the numbers off to illustrate a point about the math). One 24th of a second is exactly equal to 2.5 60ths of a second, so to make film "work" at the NTSC frame rate, you have to show each frame of film for two and a half fields of video. Since you can't (practically) have a half field, that means half your frames show for 2 60ths, and half for 3 60ths. That's why pulldown patterns are full of 2s and 3s: they average out to 24 frames per second. The 3:2 pattern works because it interleaves the 2-field frames and the 3-field frames like teeth on a zipper. The 2:3:3:2 pattern doesn't work for playback because you interleave the 2- and 3-field frames in pairs, making the footage look stuttery. In order to get why this difference matters, you need to remember that interlaced video has no frames to speak of; all it has is fields, shown in a particular way such that the afterimage of the previous frame is still fading while the current frame is being drawn. So what we write as AA BB BC CD DD really appears like this A A B B B C C D D D and so on. While the 2:3:3:2 pulldown pattern appears like this A A B B B C C C D D and so on. You get two "stretched" frames one right after the other, and that extra 60th of a second is enough to break the illusion of continuous motion. And that's probably way more than you ever wanted to know about pulldown, but whatever, I'm a nerd who likes to type. ![]()
Amazing what a sleepless night does (it gets me thinking!)... I actually don't think there's a distinction between pulldowns in 720p, since it's a progressive format by design.
All pulldown in 720p should be designed to be removed, if you look at the pattern, it's a regular pulldown, but it's relatively simple to remove on the fly because they're all full frame. Capture and select "remove duplicate frames". See if you can do that via firewire. ![]() ![]() www.strypesinpost.com
Thanks, Jeff, for the explanation of pulldown.
Today I began editing 24p footage recorded on DVCPROHD tape at 60 and captured in FCP at 60 (so the regular pulldown is still there). Do I need to be mindful of which duplicated frame I start or end an edit? What should I do when I edit with the pulldown in the footage? If there is a cadence that is created when the camera shoots at 24p and records to tape at 60, is that cadence disturbed when I edit without paying attention to the first or second or whatever duplicated frame I am selecting for my edit points? By editing with the pulldown in the footage, am I creating problems for later down the road when there is color correction and sound editing? This brings me back to one of my earlier questions: do you recommend removing the pulldown--by some method other than FCP--and editing at 24p? (The main distribution outlet is the internet.) If there is no significant advantage to capturing at 24p, I'd like to stick with the 19 hours that have already been captured at 60p (because we don't have a deck) but, of course, I will do what is best for the project. To strypes, I will try to upload footage sometime soon. Thanks.
> do you recommend removing the pulldown
Yes. See if you can remove the pulldown with Cinema Tools. It really should work, try a clip, but check the motion and see if it's jerky. ![]() www.strypesinpost.com
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