What is the difference between 24f and 24p?

In a nutshell, 24F is virtual 1080 24p.

In a nutshell, 24F is virtual 1080 24p.

24F has nothing to do with image size. 24 Frame mode is basically when a non-progressive imaging chip achieves 24P to tape, usually by means of frame blending of some sort.

-pasty

I was also wondering this, thanks for the answers. Is there one that's considered better than the other? I think I've heard that 24p is better, but is that true?

Ugh... this again. I can't believe these threads still pop up. 'sigh'...

Better is subjective. You can extract 24 progressive frames from 24f. The resolution is just as good (if not better) as any of the other HDV based 24p cameras.

...yes, and as someone said above, 24F is an simulation of 24P.

Short answer -- 24P is better. There might be some great looking 24F out there, but there's no subtitute for the real thing IMO.

Not so short answer -- neither is "better."

24F is a term Canon uses for its method of creating 23.976fps video using interlaced CCDs. F-mode processes the image (by means as yet undisclosed) from an interlaced CCD to produce a progessive-frame video file. For HDV, it lays the image to the tape as a true 23.976fps file, not 60i pull-down as is done in most "affordable" 24p cameras. So editing software that handles 24F puts it on a 24fps timeline without having to do pulldown processing, but otherwise exactly like typical 24p-from-60i video. If you use HD-SDI to get full raster 4:2:2 video or use composite-out, the 24F will leave the camera as 60i 3:2 pull-down.

So 24F and 24p are just two flavors of 24fps video. One's not a substitute for the other, and neither is inherently "better." They are just two different means of creating a 23.976fps video file. That's all. The resolution, image detail, latitude, color space, color rendition/depth, etc are dependent on the hardware and software used. The 24F from the XL H1 has as good or better image detail as any currently competing camera, but each camera has it's own particular strengths and each shooter has his/her own particular likes, so I think "better" is a rather meaningless word in the endless 24F vs 24p measurebation.

measurebation
That's an interesting word. Sometimes we are too focused on insignificant details.... seeing the trees instead of the forest.

Great word!

So, from Pete's post, I think my question I was gonna ask is answered: the 24f mode of the Canon is true 24fps, not the pulldown. So if I set an in and out point a second apart and count the frames, there will be 24, not 30 with 6 of them blurred, right? And if that's so, can we assume the new A1/G1 will do the same thing?

24P in HDV is done differently than in any other video format (I'll leave 24F out of this discussion because 24F is just a Canon name for how 24P on tape is created).

Since HDV is more or less a computer file streamed to page (an MPEG file), there's more flexibility in what data is written. Or put another way, MPEG2 had a history of multiple framerates and frame sizes long before somebody had the idea of streaming it to tape.

Ok, so a 24p MPEG stream doesn't use pulldown. That's the news. None of the 24p HDV cameras use pulldown ON TAPE. On tape is the qualifier here. The data stream is 24 discrete frames. That's it.

But, within that stream, are hints for the MPEG decoder device as to how to display that 24fps info for 29.97 devices. The hints are called repeat flags. So one frame will have an instruction tagging along with it to display for say, 2 fields. Another will have an instruction for displaying over 3 fields. You know the rest...it's instructions for the DECODER device to create the pulldown ON THE FLY. Decoder in this context means hardware decoder in a tape deck, or something of the sort.

So anyway, what this means is that some software will read the stream verbatim and tell you the footage is 29.97 interlaced, and it'll display it in this manner. Other software will be smarter and read it all as just 24 discrete frames.

There's so much confusion on the boards about this, I just had to shout it out. I'll credit David Newman of Cineform for explaining this to me once in the HD100 forum.

Excellent explanation. So I can shoot 24f with the new Canon A1, should I get one when it comes out, load it into a 24f (23.97etc) timeline in FCP (when the upgrade comes out in a couple of weeks) and I'll have real 24fps. This is good and makes me more prone to liking this camera when it gets here. I guess my confusion came from the 2 different 24p modes that the XL2 does, and the DVX100 and the HVX200 for that matter, ie., the 24p and 24pn or 24 advanced, or whatever they all call it. My understanding there is that if you shoot the "PN" or "advanced" mode, you get the "real" 24fps but you get the pulldown with the other modes. Since the XL2 and DVX aren't HDV and neither is the HVX, I guess things are different there.

You got it right. There's two reasons for the extra fancy pulldown in HDV. One is the reason I gave above, which could be distilled into "because they can".

The other reason is because imagine if 24p was inserted into a 29.97 1080i stream the way the DVX has been doing it for years. If that was the case, you'd have to recompress ALL your footage to remove the extra fields, and we all know how painful that would be in HDV. It'd take forever, and your HDV would look worse for it...more so than if you did the same with DV codec material.

The way 24p HDV is done now, no bandwidth is being wasted on repeat fields (unlike 24P DV, or even Varicam/DVCPRO HD). It really truly is clever as hell.

What's more, is that the XDCAM HD cams, Canon XLH, XHA1, G1 are all codec compatible, meaning at the NLE level, they're all equals. I suspect the new Sony V1 (or whatever it's called, I'm losing track) will do its 24p mode the same also.

The odd man out (as always) is JVC :-P

i'm missing something here ?? f , P , Cf etc

i notice the Texas shoot put list some resolution #'s for the camera's ..

canon 24f as stated in some of the post is "progressive" ( when all is said and done) i don't quite understand why the resolution is lower then interlace ? the shootout gives 800/700 for H/V resolution - and then states in frame mode 800x540?? i was always under impression that progressive has more res then interlace ?? ( or is that only on moving or shots with motion in them)

and why is the sony 350 camera 800x800 in 24p mode and then 800x540 with shutter on ? how can it drop 20% .. where'd the resolution go ??

Hey Don,

The Canon is a problem of semantics. Canon doesn't want to call it 24P, because technically, that is reserved for CCDs that are progressively scanned (and purpose built for that, which is technically more difficult and more expensive). So, they take a 1440x1080 interlaced chip, and do signal processing voodoo between the field scans off the chip, and end up with 24 discrete, full, frames per second.

Of course there's no free lunches, so the downside of this is that because they're doing weird things with fields, vertical resolution takes a little bit of hit. In the end, the signal processing outputs 24 full frames per second which is then passed along to the MPEG encoder, yadda yadda yadda.

So the Canon is not true progressive, but it does possess the most important part of a true 24p camera, which is 24 separate images per second, captured with an even interval between each image (Something the Sony Z1, with it's "Cineframe24" mode, doesn't manage to do)

The amount of vertical resolution compromised is up for grabs. A 1080 line system, with Kell factor accounted for, is only good for about 750-950 lines vertically, depending on who you ask. Worst case scenario for straight-up field blending on the XL-H1 would be 540 lines vertically. Canon's special secret-sauce DSP is somehow doing a bit better than that, but still south of what it could do in interlaced mode.

The Sony XDCAM is doing the same thing, but in the end comes out a tiny bit better (and probably only because of better glass). While lens shopping or my own 350, I put on a lot of lenses and the best I saw was a little better than 800 lines H, and little less than 800 lines V. The only difference is that Sony's 24p DSP trick somehow retains the interlace resolution but only when the shutter is off. Think of the CCD being scanned at 48 hertz interlaced, and all this starts to make more sense.

ohhhhhhhhhhh

23.976 / 29.97 / 24f / 24p / 24pn / 30i / 60 !!!!!!!


God I love PAL !

Just straight up, honest to god, 25 frames per second.

The only pulldown I do is in the toilet.

23.976 / 29.97 / 24f / 24p / 24pn / 30i / 60 !!!!!!!


God I love PAL !

Just straight up, honest to god, 25 frames per second.

The only pulldown I do is in the toilet.To be fair, the pulldown stuff really isn't anywhere near as difficult to grasp as most people seem to think it is. And we NTSC shooters have more frame rate options than you do. :)

And for the record, there's no such thing as 30i. :)

Life would have been much better had we simply given up NTSC and gone PAL and to hell with all the different HD formats. The first time I saw a PAL broadcast (when I was in Greece) I was blown away by the quality.

Life would have been much better had we simply given up NTSC and gone PAL and to hell with all the different HD formats. The first time I saw a PAL broadcast (when I was in Greece) I was blown away by the quality.

Plus you'd not have to spend the money to make the extra masters...

23.976 / 29.97 / 24f / 24p / 24pn / 30i / 60 !!!!!!!


God I love PAL !

Just straight up, honest to god, 25 frames per second.

The only pulldown I do is in the toilet.

LOL

I have to agree here. We NTSC users keep making excuses for NTSC and why we think it is good but really we have had to deal with some pretty odd crap over the years. Forget about pulldown, what about 29.97 instead of 30? How about 720x486 for uncompressed but 720x480 for DV and mpeg2? Then there is the drop frame vs. non drop frame timecode. Sometimes I really do think NTSC was thought up to be a really really sick joke. Us NTSC users spend so much time learning how to deal with all of this crap while PAL users just get to what they want to do with the video.

By the way I do know why all of the stuff above had to happen the way it did. I'm just making fun of our format.

In addition to PAL being a better format than NTSC, the broadcast TV spots in European countries are usually better and more creative than ours. They don't have to worry about prudery so much.

To be fair, the pulldown stuff really isn't anywhere near as difficult to grasp as most people seem to think it is. And we NTSC shooters have more frame rate options than you do. :)


And for the record, there's no such thing as 30i. :)[/QUOTE]

Give it a year or two and I am sure it will pop up as a new 'standard' to add to your list.

;)

okay... let me see if I got this right...

24F and 24P are just different way methods of making 24fps video... neither is "better" or "worse" than the other one.

Is it like having two cars that can both do 0 to 60mph in 5 seconds flat One is a front-wheel-dirve and the other one is a rear-wheel-drive. They are are equally fast going down a straight line.

Forgive me for hijacking but - I am about to buy the FX1, that does the Cineframe 24, correct? Would it be better to shoot 24cf and then slap it on a 23.976 timeline OR shoot 60i and convert it to 24p with a 3rd party conversion app???

Forgive me for hijacking but - I am about to buy the FX1, that does the Cineframe 24, correct? Would it be better to shoot 24cf and then slap it on a 23.976 timeline OR shoot 60i and convert it to 24p with a 3rd party conversion app???There's already a thread that might help:
http://www.dvinfo.net/conf/showthread.php?t=79589

Much appreciated.

@Nate, If Canon is calling it 24f because they are using interlace CCD's then why is the Sonys' V1 calling it 24p even though they're using interlaced CMOS? XDCAM HD is also calling it 24p. Is it because they don't lost horizontal resolution?

@Nate, If Canon is calling it 24f because they are using interlace CCD's then why is the Sonys' V1 calling it 24p even though they're using interlaced CMOS? XDCAM HD is also calling it 24p. Is it because they don't lost horizontal resolution?

Because Sony apparently doesn't feel uncomfortable stretching the truth.

To me personally, it doesn't matter. My personal definition of 24p is 24 discrete frames, each taken 1/24th of a second apart and lasting an identical length of time. I don't care how they get there, as long as it looks like what I'd get with a film camera/telecine.

The Canons, the XCDAMs, and the V1 all look fine to me.

Hey Nate,

This might be abit off topic but I wanna ask anyway lol....

The mechanics of a film camera 25fps (PAL) is achieved with the shutter going at 1/25th sec which I'm sure alot of people already knows. But for video cameras, DV or HDV, why is it that some sources recommend shooting at 1/50th sec to achieve 25fps?

The mechanics of a film camera 25fps (PAL) is achieved with the shutter going at 1/25th sec which I'm sure alot of people already knows. But for video cameras, DV or HDV, why is it that some sources recommend shooting at 1/50th sec to achieve 25fps?

You're confusing frame rate with shutter speed.

You're right, the shutter "goes off" every 1/25th of a second in a film camera (in Europe), but the same film camera will NOT have a shutter speed of 1/25th. Shutter speed is defined by how long the light strikes the film (or CCD).

So imagine in a film camera, 25 times a second a picture is taken. Each time, after each is taken, the film is advanced to the next frame. While this happens, the film has to be protected from light (shutter closed). The shutter in a motion picture camera is usually a spinning disc with a portion removed, typically 180 degrees worth.

So this means for half of the discs rotating travel the film is behind the solid part, actively being moved into position for the next frame. Then the film stops, the "open" part of the disc swings by for an exposure (180 degrees worth). As the shutter closes, the film advances again.

This means if the film is running at 25fps, it gets exposed for only 1/50th of a second (180 degrees of 25fps)

There are some film cameras that allow the shutter to be opened up to 200 degrees, as well as other cams that allow it to be closed down to 45 or 22 degrees (of which you can calculate the shutter speeds for at a given framerate). But the vast majority of film material shot is with a 180 degree shutter.

. . . why is the Sonys' V1 calling it 24p even though they're using interlaced CMOS?They are? My understanding is that to do 24p, the V1 CMOS chips scan progressively and then the camera splits each progressive frame into two fields, intersperses 12 synthetic judder frames, then lays it all out to tape at 60i.

Ah, yes. Thanks for clearing that up for me Nate. All along I keep thinking that framerate = speed of shutter, but now I know better.

They are? My understanding is that to do 24p, the V1 CMOS chips scan progressively and then the camera splits each progressive frame into two fields, intersperses 12 synthetic judder frames, then lays it all out to tape at 60i.

I've heard both. Regardless, it winds up with usable 24p however it does it.

The Canons, the XCDAMs, and the V1 all look fine to me.

Nate,

What are you thoughts on what JVC is calling the first true "completely progressive" HD image for their HD100-HD250 series?

My thought: Marketing hype.
Maybe Canon should say, "First true 24F full HD resolution progressive."

It is not marketing hype.

What they are talking about is that they finally have the true 60p broadcast format for HDV and not just limited to 30p which looks good but isn't what true 720p 60p should look like. In order to be a true progressive 720p camera it has to be able to record 60p for HD broadcast work.

If you only ever plan on shooting 24p well then it doesn't really matter. At the same time however the HD100 does not fit the full specs of 720p so it cannot be a true 720p progressive camera.


When compared to DVCPROHD, remember that DVCPROHD 720 actually only reocrds with 960x720 anamorphic pixels. This means even the 720p TV shows shot with the Varicam are not really 1280x720 pixels of resolution at 60 fps.

The JVC HD200/250 is the first 720p camera on the planet that not only shoots full framerate 60p but also records to tape the full 1280x720 pixel raster. This really is a first for 720p HD and is actually the first 720p camera to totally fill and conform to the 1280x720px60p specs.

Sweet...

So if I'm understanding what you're saying – that you can capture 60 full frames per second – then this is the first HDV camera, of its caliber and price range, to provide full progressive in-camera slow motion as well!

By this I mean recording at 60p, and then dropping it into a 30p or 24p timeline.

Is this an accurate statement?

So does 30f or 24f give you the same crystal clear still frames that 30p or 24p offer (as opposed to interlaced video)?

Is the pulldown-achieved 24p claimed by the Sony V1u really the same thing as Canon's 24f?

I'm curious about the benefits of 30f vs. 60i deinterlaced in post (besides the time benefit). Is there any difference between the two when shot with a 1/60sec shutter? That is, is the 30f image blended from two fields from the interlaced CCD, taken sequentially for 1/60sec each, just like the deinterlaced 60i?

And what happens with a faster shutter speed (other issues with faster shutter speeds aside), say 1/600sec (to keep the math simple)? In 30f, will it take one field at 1/600 and IMMEDIATELY take the second field at 1/600, make the frame, sit for 18/600, and then repeat the process? Or will it take one field at 1/600, sit for 9/600, take the second field at 1/600, sit for 9/600, just like 60i mode would? The first technique would exacerbate the stutter from the fast shutter but would maintain vertical resolution and make great stills. The later technique wouldn't offer any picture quality advantages over deinterlaced 60i (that I can see).

Of course, that's assuming your deinterlacing software is comparable to whatever voodoo Canon is doing on the camera. Has anyone made any comparisons of how well Canon's frame-mode deinterlacer compares to different deinterlacing programs you can run in post?

-Terence