Question about the 24p (60i) setting

[mpstjohn]

I'm confused about this setting on the HV20 and HV30...

How do you record 24p (24 frames per second-progressive) at 60i (60 frames interlaced)? Does the camcorder somehow convert the signal from interlaced to progressive and the frame rate after recording or during?

Canon touts the 24p recording mode on a 1080i camcorder (how does that work?). Progressive and interlaced are two very different things.

If it only emulates 24p (which is what it sounds like) can you really call it 24p Cinema mode? Wouldn't "faux 24p" or "pseudo 24p"? make more sense?

It seems the two pictures on the canon website (one 60i, the other 24p) that they use to demonstrate the difference is only the work of some color correction (I don't understand how you could judge frame rate from a still image anyway).

Wouldn't recording at 30p make more sense than this 24p Cinema mode, since, at the very least, you're actually recording progressively, and only 6 off on the frame rate?

I was thinking of buying a refurbished HV20 (since its basically the same features as the HV30) but the more I hear about the 24p cinema mode the more it seems it would be worth it to wait longer and buy the HV40, which has Native 24p (recorded at 24p).

[Rumpelgeist]

How do you record 24p (24 frames per second-progressive) at 60i (60 frames interlaced)?
http://en.wikipedia.org/wiki/Telecine#2:3_pulldown

Canon touts the 24p recording mode on a 1080i camcorder (how does that work?). Progressive and interlaced are two very different things.
http://en.wikipedia.org/wiki/Telecine#Video_cameras_that_produce_telecined_vide o.2C_and_.22film_look.22

Wouldn't recording at 30p make more sense than this 24p Cinema mode, since, at the very least, you're actually recording progressively, and only 6 off on the frame rate?
http://en.wikipedia.org/wiki/Telecine#2:2_pulldown
http://en.wikipedia.org/wiki/Progressive_segmented_Frame

I was thinking of buying a refurbished HV20 (since its basically the same features as the HV30) but the more I hear about the 24p cinema mode the more it seems it would be worth it to wait longer and buy the HV40, which has Native 24p (recorded at 24p).
http://en.wikipedia.org/wiki/HDV#HDV_1080i
http://en.wikipedia.org/wiki/HDV#HDV_1080p

Don't be shy, try using google or wikipedia yourself, it does not bite.

[Lunchbox]

Most of your questions are asked and answered many times in the forum. You might want to spend some time to read the forum and stickies, as well as the FAQ.

HV20 24p mode is called PF24 within the camera. It is a 24p video wrapped in 60i with pulldowns inserted. In that case, your video can be playback on NTSC TV directly (You can't view 24p video on TV without the telecine process).

HV20 equipted with progressive sensor.

You can obtained the 24 frames from PF24 video thorugh pulldown removal. Again, you can read about it in the FAQ on how to remove pulldown.

HV20 doesn't come with 30p.

Is there any particular reason you need to record in 24p? I do wedding videos. 60i and 30p works great for me.

[mpstjohn]

Is there any particular reason you need to record in 24p? I do wedding videos. 60i and 30p works great for me.

24fps has always been indicative of actual film for me. Whenever I spot a movie shot at 60fps (Star Wars prequels, Hatchet, movies on the scifi channel), its hard for me to take it as a film. It's looks like a home movie shot on an expensive camera, rather than an actual film. In the case of films with visual effects, it makes the effects seem faker (particularly with green screen effects) and screws with the depth of field for me.

I'd rather shoot something at 24p, with a 35mm adapter and putting it through FCP6, clip the aspect ratio to 2:35.1. If I have to settle for 30p it would come to that, but it looks like pulldown removal (I was under the impression until now this could convert interlaced to progressive, but not change the frame rate) could fix that.

Thanks for your help.

[Lunchbox]

no pulldown is inserted in 30p.

pulldown is also not to convert interlace to progressive. That process is called Deinterlacing.

[mpstjohn]

no pulldown is inserted in 30p.

pulldown is also not to convert interlace to progressive. That process is called Deinterlacing.

I was under the impression that deinterlacing wasn't "true progressive".

[Lunchbox]

That's correct. Deinterlace wasn't true progressive.

[Rumpelgeist]

I was under the impression that deinterlacing wasn't "true progressive".
Deinterlacing is an action. Progressive is an attribute, a property. So naturally, deinterlacing is not progressive.

After you deinterlace your video, it becomes progressive. Depending on how you shot it and how you deinterlaced it, it may bear different level or similarity to true progressive video, that is to video that was captured, processed and recorded progressively.

You may also want to google for "interlaced chroma" and "progressive chroma".

[mpstjohn]

Does the "native 24p" feature make the HV40 a 1080p camcorder, rather than a 1080i camcorder?

On these forums there seems to be some debate as to whether it makes much difference going from 24p (60i) to native 24p, but I'd think "native 24p" would mean true progressive (hence better quality), and pulldown would mean later deinterlacing, which would mean the quality of the picture would depend on what product (and maybe how expensive the product) you would deinterlace with.

[2Bdecided]

If you'd followed any of the links provided, you'd know pulldown itself is 100% perfectly reversible.

The issues with 24p-in-60i are :
1. the time taken to do the pulldown with free methods,
2. the interlaced chroma issue, and
3. the potential quality hit caused by MPEG encoding hard pulldown content

Cheers,
David.

[mpstjohn]

Lunchbox just said that pulldown did not deinterlace the footage. So there is no difference between "true progressive" and deinterlaced footage. Get a good enough deinterlacer and you can't tell the difference.

Going back to the links it seems the native 24p would actually be 24psf (since its interlaced equipment), the hv30 does a 2:3 pulldown inside the camera (or at least most of these sorts of cameras do), the hv40 is 24psf without the pulldown.

So the only difference between the hv30 and hv40 is the 2:3 pulldown. Got it. Thanks.

I might as well get a refurbished hv20 then I guess.

[Rumpelgeist]

Native 24p is native, not PsF. At least it is delivered as native over FireWire, I don't know for sure they way it is stored on tape.

[um3k]

I suspect the footage is stored on tape as 24p with repeat field flags, I.E. the same as a DVD.