Can 720 30p be converted to look like 24p?
 

Has anyone shoot in 720 30p and tried in post to get the same
look and feel of 24p footage? Any thoughts or ideas or experience,
please share. thanks...

It's possible if you use some kind of motion-based interpolation, but that kind of software is pretty expensive. I'd just leave it alone unless you're outputting to film, very few will be able to tell the difference.

I see a big difference between 30p & 24p footage from the
HD100U. It is a very different look from 30p to 24p.

What editing software are you using? We are using FCP 5.1
and conform 30p to 24p using Cinema Tools. Most legacy stock footage is plain vanilla 29.97. Many clients are requesting some 30p to 23.976 conversions.

Not saying you are wrong, but we know 25p doesn't look different than 24p. So when you say you see a BIG difference, that big difference would have to occur at 26, 27, 28, 29, or 30p. Hard to believe it would be 26. So that means something dramatic must occur at 27, 28, 29, or 30p.

Given equal 180 degree shutters, I can image a tiny difference -- but a big difference -- I'm not convinced. In fact, film for commercials has been shot at 30p to avoid pull-down.

So, I suspect what the difference is -- is that when you watch 24p on a video monitor you are seeing 2:3 pulldown. That is the BIG difference. BUT YOU DO NOT SEE PULLDOWN WHEN YOU WATCH FILM IN A THEATER.

Therefore, you should be able to get a TRUE film look using 30p. In fact, a more true film look than shooting 24p!

Unless you really go to film, shooting 30p -- with each frame presented twice upon video viewing -- is very much like film where each frame is flashed twice by the spinning shutter. You get the SAME strobing artifacts.

You get nearly the same shutter speed and nearly the same frame rate.

That's the virtue of 30p -- plus no editing issues.

why does 30p look more like film than 24p? cuz of the "strobing artifact"? why is getting "nearly the same frame rate" better than getter the actual frame rate of film?

Steve's point is that there is no way to actually view true 24p. Almost any way you view it comes out as a 3:2 pulldown, which has a jerky feel to it.

Exactly! Amazing that folks think by shooting 24p they will be able to view 24p. They can only see 24p if they convert to film.

If you are not going to film -- you'll see 60p or 60i with 2:3 pulldown when you watch on ANY video screen. The 2:3 "judder" look is NOT the same as the "strobing" that comes from 24p film or 30p video. Completely different!

Which means if you really want a TRUE "film look" -- shoot at 25p or 30p.

Which is why the HD1/HD10 works fine for a film look even though it doesn't have 24p.

Hi Steve,

What if you shoot 30p and you end up going to film?

Maybe that's a good question for Andrew Young?

(I would love to shoot 30p because FCP does it natively now)

Thanks,

Tom Chaney

(and for those of us that have already started shooting in 24p, can we mix footage?)

Andew Young shot at 30p and when output to film let is play frame for frame, meaning that it was 30p but projected at 24p giving you a very slight slow mo effect. Obviously if there was sound this would cause a problem but his footage did not have it and he mentioned he liked that look for his nature footage.

If you think you might go to film then shoot 24p. If not, use 30p, the progressive at 30p will give you a good look. If you only believe that you can get the real film look by doing 24p then shoot it but what I realy suggest is that you shoot the same thing at 24p and 30p, then burn a DVD and watch it on your tv. See what you think and make your own artistic decision.

If going to DVD..
If you like the look of 24P movies when viewing DVDs, than capturing 24P with the HD100 and transfering to DVD should yield the same look.

This is a correct statement, right?

I believe the original question was "Can 720 30p be CONVERTED to look like 24p?" I assume that Rob is asking this question because the footage is already in the can, and we're not talking about what he _should_ have done...(?)

Rob: It is much easier to convert 60i to 24p than 30p to 24p. Film houses that transfer video to film generally don't accept 30p source material, whereas they will gladly accept 60i source material. The reason for this is that interlaced video has greater 'temporal' resolution, whereas progressive video arguably has greater spacial resolution. When you convert from 60i to 24p you have at your disposal a set of snapshots at every 60th of a second which can be matched convincingly (for some) to 24 fps with a 3:2 pulldown.

If you have started with 30p, you could convert it to 60i, then down to 24p again. When you do this, however, you will still discover that the 2:3 pulldown produces a move-jerk-move-jerk kind of feeling, because wheras 24p has captured 1/48th of a second of motion at intervals of 1/24th of a second, 30p has captured 1/60th of a second of motion at intervals of 1/30th of a second. Frame number one will be identical, frame number two will be out by .008 seconds, frame number three will be out by .016 seconds, frame number four will be out by .025 seconds, and so on.

These may seem like small differences, but the eye will detect it, even if your motion-interpolation software is excellent.

Short answer: I'd leave the footage the way it is, at 30p.

I'll throw my hat into the ring on this one...

When shooting film for broadcast and a monitor is visible in the shot, there are two typical ways to avoid a roll bar in the screen; have the playback video converted to 24 fps (with a capable monitor) or shoot the film at 30 fps which will sync with video.

If the latter process is chosen (not very often these days), there may be a single shot of 30 fps transferred at 30 cut in with 24 fps transferred at 24 fps footage (I make the transfer distinction because, as being discussed above with Andrew's footage, transferring at a different frame rate results in an undercranked or overcranked appearance). The result of this is a cadence that looks very different than that of the surrounding shots, enough so that I used to say to myself "here comes the pan to the TV" when such a shot would appear. It's pretty obvious. Not huge, life-changing or radical, but if one's eyes are attuned to 24 fps, it's apparent.

Now, I've also sat in a dailies projection room and seen film footage projected at 24 and then occasionally sped up to 30 (in an effort to plow through hours of dailies). There is definitely a difference in appearance with 24 and 30 fps projection. It's quite similar to viewing 24p vs 30p originated footage on a monitor, regardless of pulldown or no pulldown being in the mix. It has something of a "video" look to it, in fact.

Steve, while it's agreeable that the difference between 24 and 25p is hard to detect, I think it's not too hard to imagine that the CUMULATIVE effect of the incremental alteration of information between 24 and 30 can result in a visual change. Much in the same way that Andrew's footage shot at 30p had a noticeable slowdown when transferred frame to frame onto 24 fps film, yet films shot at 25p and transferred to 24 do not.

I don't disagree that the move from 25p to 30p will be visible to some. My original point was that the BIG difference someone saw was more likely the 2:3 pulldown ON vs OFF -- than the change in rate.

My second point, when questions were asked, was that we really should differentiate between a "Telecine-look" verses a "Film-look." I'm not saying one is good and the other is bad. I simply realized that a whole bunch of new folks are shooting 24p without an understanding of what they were really getting.

My third point, is the vast majority of low-temporal rate video will NEVER go to film. And, given the hasstle of capture, mixing with deinterlaced 60i, and export -- there is an advantage to shooting 30p.

When you say you can see the difference of a 30p shot within 24p, I'm not sure this can be generalized. First, you know the shot is coming. Second, it is a switch from one rate to another. Third, I'm not sure if the scene were lit as though it were film, the typical audience could see much of a difference.

Now, if you really want to create a "look less like video" at 30p -- turn-on the Motion Filter. This adds a judder to pans that will likely trick most of the audience.

And, that's what "film look" is about. It's only a trick to fool the audience into believing either that video wasn't used or that film was used.

I'm watching a lot of films from the `70s and `80s on INHD. These film have wonderful grain. There is no way IMHO that any video camera is going to give a result that looks as good as these films. To me, film has a texture that 24p video does not. (I love the grain in my old 16mm film.)

So when you say that 30p has a bit of a video look -- I feel modern film stocks have already moved film toward looking like video. No wonder Lucas can make the switch to all electronic motion pictures.

Just a question, if you shoot 30p and end up going to film, why not just project the film at 30 fps in the theater? I recall that movie studios stick with 24 fps despite TV's use of 60i because going up to 30 fps would increase their film costs 25%. If you're willing to pay for the extra film in the end, though, why not just avoid 24p altogether and project at 30?

Besides film doesn't 24p have an advantage over 30p on DVD's as well?

I thought 30p DVD's only worked as 30p put into a 60i mpeg2 stream. When this is watched on a progressive display the 30p frames would get bob and weave thinking that it was 60i. This means highly reduced vertical resolution with no framerate gain since there is no second field of data.

I thought progressive DVD players only looked for the 24p. I thought I read somewhere that 30p with true progressive frames and progressive flags wasn't in the DVD spec. I could be wrong here though. Maybe I should try burning a 30p DVD tonight and see what happens.

In fact, a lot of 16mm/35mm projects that I've been involved with was shot with a cinemacontroller running at 29.97 and transferred via Rank or Datacine to DigiBeta
(w DiaVinci Color Correction) at 29.97, so we would get a sharper look. Like stated earlier it is more expensive)

I've noticed that 24p looks softer than 30p.

But so far as going 30p back to 24p, I don't know if a transfer house can do that with progressive yet.

Several claims made in this thread are ... well... just not right.

First: 30p doesn't look more like 24fps film than 24p does. The assertion is simply nonsense. 30P never looks like film. It looks like a halfway hybrid of film/video. 30P may look like film that's been shot at 30fps, but that's a very rare case, as Charles pointed out.

Second, yes 24p DVDs have a definite advantage over 30p on DVD. DVD players have been designed from the beginning to work with 24p footage; it's one of the requirements Hollywood insisted on. So you can author a 24P DVD from 24P footage and it will play back at 24fps on a progressive monitor, or with 2:3 pulldown on an interlaced monitor. You can store more footage in 24p on a DVD, or use lower compression to get better quality out of the same amount of runtime. And the compression is cleaner and more efficient than the 60i compression.

Third, the assertion that you never see 24p outside of a movie theater is just wrong. If you've ever watched a DVD on your computer, or played a DVD on a progressive DVD player to a plasma, LCD, or other progressive monitor, or watched a movie trailer on the web, or... well, basically watched on anything other than a CRT, you've watched 24fps with no pulldown and no interlacing.

Fourth, we're extraordinarily accustomed to watching 24fps footage with pulldown. Every network drama, every sitcom, every movie-on-TV, every VHS hollywood movie, every DVD we've ever watched on a regular CRT television for the last 50 years has been 24fps with 2:3 pulldown. And that's the look that 24p cameras deliver. To argue that 30p footage looks more like film on our televisions than what actual film looks like on our televisions is... well, it's just wrong.

24P gives you options. It looks like film. It can be authored to a 24P DVD. It can be transferred to film. It can be easily converted to PAL 25P. It's the "universal" format.

30P is basically an orphan format. Makes for a lousy conversion to PAL, can't be converted to film well at all, and looks like a hybrid cross between film and video, offering the worst of both worlds. It's a choice, it's an option, but there's a reason that it's a rarely-selected choice.

If you want your footage to look like film, shoot 24p (or, in EU, 25p).

30P is best reserved for either a) a mild overcranked slow-mo look when inserted into a 24p project, or b) a smoother-motion alternative to the strobier 24p, when shooting events that you don't want to have look like film.

Even if you are watching on a progressive scan monitor, you're not necessarily avoiding pulldown. Watching movie trailers on the internet, for example, unless your computer monitor is scanning at 72 or 96 Hz, there is definite pulldown, and possibly image tearing (when a frame advances in the middle of a scan) occurring.

Barry, thank you for taking the time to make things clear.
I think it is safe to say most people who bought
the HD-100U cameras are due its true
720 24p ability.

30p looks like home video compared to 24p.

I use FCP and have to do some twisted things
to edit the 24p footage. Apple & JVC have taken
so long to provide any real turnkey solutions.

NAB came and went, and nothing immediate....

Just trying to learn more "workarounds" to get
the best results until FCP supports our 24p format...

Well, image tearing, yes, but pulldown?

You're seeing 24 frames played per second. There's nothing added to round out that sequence (which is what pulldown is). 24 times per second you'll see a different frame displayed.

I mean, in the movie theater you also see a bit of an effect from the fact that the shutter closes, and not instantaneously -- it's a rotary disc, so it closes from the top to the bottom over the course of typically 1/48 or 1/72 of a second. But you're still seeing only 24 images per second. And that's what the computer monitor is giving you -- 24 discrete images per second, equally spaced in time at 24hz intervals.

Pulldown is a way to round out the sequence because 24 frames doesn't divide evenly into 60 fields on TV.

It would be correct to say that you're not seeing 24 full frames displayed for 1/24th of a second artifact-free and flicker-free, even in the movie theater, due to the way TV screens draw and due to the way film shutters close. But pulldown is a separate concept; pulldown is how the JVC embeds 24fps within its 60fps data stream on the analog outputs -- one duplicated frame out of each group of four. But that's not what happens when you watch a 24p DVD or 24fps film projected.

I had the impression the HD100 records a true 24fps, something like the hvx's 24pN. But now you're saying it capturing 30 and flagging six frames?

No, the HD100 scans a true 24fps signal. But HDV 720p doesn't provide a recording format for 24fps, its only options are 25, 30, 50 or 60. So in 25p mode, yes it's just 25 frames and only those 25 frames (AFAIK). But in 24p mode, it's 24 frames carried within a 60p data stream. Sort of like the HVX does in its "over 60" mode, but much more efficiently, because the "pulldown" frames aren't actual recorded frames that take up bandwidth; instead they're just "repeat flags".

So almost all the available bandwidth is used to record only the 24 frames, but it's not transporting a 24p stream, it's a 60p stream. Some editors recognize the files as a 24p stream and know to ignore the pulldown/repeat flags, other editors or programs recognize it as a 60p data stream.

For all practical purposes it is indeed using its bandwidth to only record the 24 frames, as the pulldown flags don't really change anything.

At the risk of Thread-jacking, I must admit that I'm confused here. I may have missed something, but the way I'm reading the 24p/30p DVD thing is that a progressive player, hooked to a plasma/LCD/other progressive display will display 24p. But 30p footage HAS to be converted to 60i? Or am I just completely off base here?

I know there are numerous displays out there that can handle 30p, but it seems to be a bit of a moot point if the only way to actually get 30p into them is via the camera or a computer.

If you watch a film broadcast over NTSC you're seeing 24 frames played per second as well. It's just pulled down. Your monitor, regardless of whether it's CRT, LCD, Plasma, whatever, scans at a fixed rate per second just like a regular television. Unless your monitor is refreshing at an exact multiple of the source framerate (i.e. 72 Hz for 24p content), your video card has to either pull it down or simply put up a new frame every time it gets one regardless of where the monitor is in its refresh cycle, resulting in tearing.

You can set the refresh rate of most CRT monitors to avoid this. I'm not sure about LCDs, having never owned one (I don't trust their color). Monitors made for modern home theater setups can generally change their scan rate depending on what kind of content they're trying to display.

Non-CRT displays are 60p. 24p must have 2:3 pulldown added to get to 60p. 30p must have 1:2 pulldown added to get to 60p.

High-rez. computer LCDs, in fact all LCDs, plus plasmas and DLP run at 60p.

Which means only a few LCD computer monitors and CRT monitors run faster than 60Hz. Everything is converted to 60Hz.

The ideal would be 72Hz since 24Hz could simply be repeated 3X. But, technology isn't quite able to do 72Hz yet at a reasonable price.

Interesting. Neither Sony or Panasonic even make CRT monitors for video so the color issues are really gone. Black level is the remaining problem.

DVD players can encode two types of footage streams: 24p, or 60i. So if you shoot 30p, you'll be using the 60i file encoding method. And your footage will be displayed as sequential fields, not as whole progressive frames.

So even when I watch a 24P Quicktime file, a pulldown is being used?

I'm no longer certain after reading this when one should employ 24p. Is it for filmout only?

1) The 30p will be carried within 60i -- but 30p does not become 60i.

2) It will NOT be displayed as sequential fields because a non-CRT can't display fields!

So the odd and even lines (not fields) will be reassembled back into a frame. The frame will be repeated twice. Just like 25p becomes 50p or 100p for display. No 2:3 pulldown judder at all. Only the natural strobing which is an eye tracking artifact from 24p converted to film, or from 25p, or from 30p.

Film, 24p, and 25p are identical except for the rate the frames are presented. The difference in rates may or may not be significant. But that's an issue of what look you want. And, how much work you want to go to edit your video. For example, some programs will incorporate 60i video -- it's a lot simpler to deinterlace 60i to 30p. Others may need to incorporate film. In which case 24p will be more compatible.

It's still a matter of taste. And, a matter of effort.

But if the DVD specs do not allow a 30p format will a digital display know how to convert 30p to 60p by duplicating the frames? The question here isn't if 30p in general will display but if 30p on a DVD will work correctly. As far as I know you cannot do a 30p DVD where the flags will be set so the DVD player will add a 2:1 pulldown to duplicate the frames and turn it into a 60p stream. I thought DVD pulldown only worked on a 60i sequence. Again I could be wrong here so hopefully you can clear this up.

If you can do a true repeat flag 30p DVD then what steps should be made in order to do this? I'm sure most people just assume to make a DVD as normal without setting the correct progressive flags. If you make a normal DVD from 30p it in the end wouldn't be much different than a 60i DVD.

Finally do most encoders know to treat 30p video as 30p with the flags? I would think that if this is a valid DVD spec some encoders might be dumbed down since it isn't a very common spec.

30p on a 60i screen should show up as proper 30p without artifacts. When the monitor scans two fields that are really part of the same frame, the effect in the end is that it has really scanned one complete frame because there is no temporal difference between the fields.

It's exactly the same which is why you do not need to do anything special. No worries about encoding. No worries about decoding. (Which dosen't mean that some software can't do 30p.)

But, that does not mean it isn't a 30p DVD! That's because what makes video progressive is the CCD and the process of encoding and the process of display. It is not the means of recording to tape or to DVD.

Specifically, when 30p is ENCODED the progressive video is far more efficiently compressed than interlaced video. That's the virture of 30p vs 60i. That is the DIFFERENCE.

Once encoded, remember that 60i is 30 FRAMES/S exactly as is 30p.

To display, the 30fps is doubled to 60Hz for display.

And by the way I have shot nature footage at 30fps even though it was not 24fps I personal think you can get a film look to it by tweeking the settings in the camera. Some of the footage I have shot at 30fps I personaly think and others have said that looks like film, they actualy thought I shot the footage at 24fps. No one has ever said they thought it looked like video nor do I think 30fps looks like video at all and I also do not think 24fps looks allot better than 30fps. If your not going to convert your project to film I think 30fps is just fine and looks great and is easy to edit. I think that is pretty much what Steve was saying earlier, but if Im wrong Im sure Steve will correct me.

As you can tel I think allot.

Gary, do you use Final Cut Pro?
Is there a special/optimal formula using Cinema Tools
to convert 30p to 24p and get that further film look?

Does anyone have any results or side by side comparrisons
for the related topic?

You and I are thinking alike on this matter. I've not mentioned this option for several reasons:

1) I expected full 24p support from everyone by NAB.

2) I had not focused on incorporating legacy material into HD.

3) I was expecting a very harsh counter attack.

My version of history is that the desire for 24p came from those who wanted to make films. When Panasonic released the DVX100 it gave folks the chance to shoot real 24p. Filmmakers were overjoyed. The correct mode for going to film was 24PA. But, lots of folks shot 24P and liked the look -- even when they weren't going to film. Suddenly, everybody wanted 24p "video."

Since many of these folks had no technical background, they really never worried about "pulldown." They liked the "look."

During this period the world transitioned from SD to HD and from interlace to progressive displays. I think it's fair to say that many of those buying 24p HD cameras have zero experience with HD and many may not have big-screen HDTVs or huge-screen projectors.

With neither a technical understanding nor experience, they have no choice but to follow the trend and listen to "experts." Shooting 24p is a "faith-based" effort.

I suspect that a large proportion of those shooting 24p would be far better off shooting 30p. This is particularly true if interlaced material needs to be incorporated in your production. Likewise, it you are going to export to HDCAM or DVCPRO HD, your 30p timeline moves to 60i with no issues. Likewise DVDs are easily made.

Folk's should understand that carrying 30p within 60i does NOT change the nature of 30p. The display will make a frame and display it twice -- just like a film projector does. In short, 30p is automatically handled in a 60i world. Just as 25p is handled in a 50i world.

If you use a 1280x720 display, you will have a pixel-for-pixel transfer from the CCD to the display. (This is also true of 24p.)

If there is ANY chance you'll be going to film -- then obviously you should shoot 24p. Or, if you incorporate telecined film (which has 2:3 pulldown) you want to remove the pulldown and place in a 24p timeline.


Lastly, for those too young to remember:

In 1955 the Todd-AO 70mm film system used a 65mm negative running at 30fps. The first major film shot in Todd-AO was Oklahoma!. This print was shown in big theaters in major citites. (The second film was Around the World in Eighty Days.) For general release, they also shot Oklahoma! in 24fps Cinemascope on 35mm stock.

Here's a comment on how 30fps looked: "The difference does not seem great, but the sensitivity of the human eye to flickering declines steeply with frame rate and the small adjustment made the film appear noticeably less flickery, steadier, and smoother than standard 24fps." Does seem anyone thought it looked like "video." :)

Now, can you imagine if the 30fps were compared to 24p WITH pulldown. If real 24fps appears less stready than 30fps, image how much less stready 24fps with judder will look.

But, if you want that judder look, fine. But please don't call it "film look." It is Telecined look." Film does NOT have judder.

Want to see 30p?

The Oklahoma! DVD features a transfer from the 30fps Todd-AO print. The DVD material is decoded as interlaced fields, but unlike video, pairs of fields do belong together. Therefore the DVD player uses 2-2 pulldown where pairs of fields are woven together and each displayed twice (2-2-2-2).

Yes Final Cut Pro is my choice for editing but I do not convert to 24p I shoot and edit at 30p State Park and nature videos stuff like that. I like the look I get with the settings I have in my camera for those particular types of shoots, plus you can always make adjustments in post if you want to tweek your look a little more. I dont shoot in 24p and I will probably never use 24p I like a film look or flaver to my video and I think I have achieved that just fine at 30p friends who have seen my work say the same thing. So if I like it and they like it then that soots me just fine. If I ever want to shoot a documantary or something I know I will bump up to film then I always have the option to shoot at 24p but I dont think I need to shoot 24p to get a film flavor to my outdoor work.

I think you've got the answer -- there is no need to convert 30p to 24p to have a film look. And, you can't do it even if you wanted to.

24 & 30 - viva la difference!
 

There has been a lot said on this topic already, so forgive me for adding a little more hot air to an already wilting subject, but here goes…

For me, 24 & 30 definitely have their aesthetic differences, and each also has their useful applications. On a number of occasions I have shot film at 29.97 because it was going to be telecined and we did not want pulldown artifacts. The transfers looked great. Nobody said the stuff looked like video, but the material did feel more "real" than 24.

Obviously, there are a number of factors both artistic and technical that contribute to a "film look," but on the digital camera side I believe it has at least as much to do with progressive capture as it does frame rate. For me, there's a bigger difference between 60i and 30p than between 24p and 30p. Of course, at very high frame rates progressive capture can start to mimic the temporal sampling of interlaced video. I have seen this when I shot something at 100 to 200 fps (on film) and then sped it up in post to bring it back closer to real time (oops, I shouldn't have over-cranked when that bear was yawning). Believe it or not, the stuff starts to look like video. Very weird, indeed. Obviously, temporal sampling and shutter speed play a huge role in the "look."

Anyway, since the reasons for not shooting 24p have been eloquently stated above, let me stand up for the beleaguered frame rate and state a few reasons why I often choose to shoot 24p (besides the filmout argument):

1) to me 24 fps feels more like an abstraction of reality than 30p or 60i and in that sense it feels more like storytelling than say, reporting. It goes back to the whole temporal sampling thing. Like using diffusion, or playing with shadows, I find temporal under-sampling to be more conducive to story telling. It takes me on a journey more readily than the faster, more reality-like rates.

2) when 24 fps is the time-base of your project you can do more with slow motion. All of a sudden, 30p is a nice mild slowdown and 60p (I'm holding my breath for the HD250) is a really nice 2.5x slowdown. Not everybody cares about this, but if you do, basing your project in 24p really helps.

3) 24p is more bandwidth efficient, offers more bits per frame, takes up less hard drive space, renders in less time, is less processor intensive (yielding better realtime performance) and produces better encodes per unit of storage. - Of course, if you can't edit it without transcoding to another format, you can toss the storage part of this argument out the window:).

4) And of course, there's the filmout argument. No progressive rate other than 24 or 25 should ever be used when going to film. Period.

Yes, 30p may be a better aesthetic or practical choice for many kinds of projects and I do often use it. But 24p is alive and well in my tool kit. Isn't it great to have choices?!