24P vs 25P

H

HaroonGhauree

Active member
NOTE: Following information is restricted to only my personal understanding. There is always a possibility of being wrong !!!

Hello,

I live in a PAL-oriented region so I have to buy DVX100BE/BEN instead of DVX100B.
My understanding about the difference b/w 24P and 25p is that they both have their native advantages and disadvantages as follow:

:Drogar-Thinking(DBG 24P is actually a pull-down version of native 30P captured video footage. This may introduce some artifacts (in other words quality loss) in the footage by the electronics of camcorder. :Drogar-Dum(DBG): But! 24P also eliminates the need of any major conversion before transferring to film.


:Drogar-Dum(DBG): 25P is native and captured by the camcorder electronics without any loss i.e. quality footage closer to 24P. :Drogar-Thinking(DBG But! 25P to 24P pull-down in post-production may introduce the artifacts which were otherwise introduced by the 24P camcorder electronics mentioned above.

:Drogar-Smoke(DBG): Making the whole story short DVX100B series is ideal for indies and 24P is the order of the day. Everyone either coming from 30P or 25P world wants to somehow transfer their masterpieces to 24P. Also, both types of people will face the similar kind of quality loss either before or afterwards in their production workflows. But I think the 30P/24P people are at low risk as the things are getting done and taken care by fine camcorder electronics while 25P people are a bit orphans as they are left with their technical skills and knowledge to convert their 25P quality footage to maybe a rather low quality 24P footage in post-production using possibly a Software. My point here is the same footage taken from the same camera may look different for different 24P pull-down schemes done by different variable skilled people.

:Drogar-BlackEye(DBG My questions to both the gentlemen and the whole DVX community:

Q1. How can one say there is no difference between 24P and 25P except the 4% speed slowdown without introducing unconscious-jerk to a viewer ?

Q2. How come Panasonic introduces a PAL version without a 24P native mode ?

Q3. Why Panasonic is misleading about the 24P/Advanced 24P (i don't know the difference) mode as it is infact a pulldown version of native 30P capturing ?

Q4. Why there in no such true, pure and native 24P specific camcorder mode ? ( i.e There must be camcorder electronics dedicated to native 24P capturing instead of any pull-down ! )

Thankyou.
 
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Sorry, you have it all wrong. 24p doesn't introduce any quality loss when shot 24pA. It's saved to tape in a 60i format, but the drop-frame gets dropped and the other frames suffer no quality loss.

25p doesn't suffer any quality loss when time-remapped to 24p, either. It's frame to frame, no loss.
 
24p is not ever "native 30p." The DVX shoots 24 progressive pictures per second (actually 23.976, but it's the same thing.)

When it shoots 30p, it's 29.97 progressive pictures per second.

One can say that there's no difference between the DVX's 24p and 25p except a 4% speed difference because other than that, there's no difference -- except differences between PAL and NTSC (resolution, color).

There is no DVX which records only 24p to tape because it must record to tape in DV, and DV doesn't support native 24p. This is why there's pulldown added when it's recorded.

There are HD camcorders which do record to tape as 24p, and the HVX records to the P2 card as pure 24p if you want it to.
 
Steps to get 24P out of 25P !!!

Steps to get 24P out of 25P !!!

Ok ... I got it all wrong first ... Thanks to you people correcting me ...

George Lucas upon shooting "Star Wars II: Attack of the Clones" in HD said that he would keep the captured pure 24P footage as his master-piece to output in various old and new distribution formats like broadcasting and optical disk formats. Now we see the old SD-broadcasting format and new HD-broadcasting formats beside old CD/DVD and new Blue-Ray and HD-DVD ...

Now I have a few more concerns of getting pure 24P out of 25P (50i in actual) ...

Goal: To get pure "24P Master" footage out of 25P ...

Scenario: I've recorded 25P footage. I want to capture it using Adobe Premiere Pro 1.5. I created a new project with default PAL 50i settings (since there is no 25P project). I got the footage in the form of clips. I edited it to get my final sequence. Now I will follow the steps below to get '24P Master'.

Steps:
1- I slowdown the speed to 4% on the same 50i time-line.
2- I export the footage as a PAL 50i movie (since there is no 25P export) without checking 'de-interlace' option. (I also want to know the function of 'optimized frame' ...)
3- I create another project of 24P time-line in Adobe Premiere Pro 1.5. (I need to know the nature of 24P project. Does it expect a 29.67 footage or pure 24P footage ...)
4- I import the 50i PAL 4% slowed-down movie i just created into the 24P time-line.
5- I saved the project to have '24P Master'.
6- Now from my 24P Master, I may export to any distribution format in the world ... :happy:

My Points:
Q1: Are the specified steps correct ?
Q2: Am I missing something in the '24P Master' work-flow ?
Q3: Will 4% speed cut-down to get '24P Master' give exactly the same 'psychological look n feel' as a 35mm film camera produces in terms of unconscious speed ?

Remember: Exactly same steps are needed for both SD and Wide-Screen projects ...

Any suggestions ...
 
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Technically speaking PAL standard is better than NTSC.

Resolution: PAL-720x576; NTSC-720x480
FPS: PAL-25FPS; NTSC-30FPS

But, I must say that progressive NTSC-Camcorders like DVX100 support true 24P natively in addition to 30P and 60i modes. While progressive PAL-Camcorders usually support 25P and 50i.

Also, popular NLEs do provide 24P timeline from these NTSC-camcorders, hence making the whole 24P-Master almost seamless. Creating PAL-50i for 25P footage looks pretty normal but not seamless. I must say they should also include a 25P timeline project settings for non-technical guys like me. Also, the progressive camcorder manufacturers do provide 24P mode in there PAL version. Same goes with NLEs vendors. They should provide dome kind of filter to transform 25P to 24P rather than technical know-how about 4% speed cut down etc.

Since, I'm not sure about the purity of my acquired 24P-Master after conversion from 25P by slowing down my timeline by 4%. I still can't comment on this now. I'll also keep my 25P-Master rather than 24P-Master until then :embarasse

Note: If there is a separate circuitry involved in 24P then it should also be included in PAL-version. If the same NTSC circuitry involved in getting 24P via an additional circuitry it should also be included in PAL-version. I wonder why PAL-version is left out of 24P native mode and considered 24P done by the PAL-filmmaker in post where NLEs don't support 25P-timeline and 25P-to- 24P transformation filter. I'm talking about 'Usability' and '25P-to-24P Seamless Process' and I know it will be incorporated sooner or later in both camcorders and NLEs.
 
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If you want to output your master to film be happy you have a 25p (PAL) master as it has more resolution. The process of outputting to film is not 'seamless' anyway, so not an issue at all.

If you're outputting for TV, DVD or the internet you won't need a 24p master either.

By the way there is no special image/resolution loss because your outputting from 25p to film. The 25 frames you have recorded per second are just played back at 24fps. And the eye doesn't see the difference. The only real change is to the sound that is made to sync-up to the new frame-rate.

In Europe tons of films are shot in 25p and are shown in the cinemas at 24fps, no biggy. As long as 24p isn't needed your time is probably better spent on something else than converting the master you already have.
 
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David Jimerson said:
24p is not ever "native 30p." The DVX shoots 24 progressive pictures per second (actually 23.976, but it's the same thing.)

When it shoots 30p, it's 29.97 progressive pictures per second.

QUOTE]

Actually - just to make it more confusing. When in 30p or 24p or 24pa mode the camera is always shooting in a 29.97 progressive stream and adding pulldown flags to the 24p/pa modes.
Click to expand...
 
..and to correct ncje slightly .. the camera is always RECORDING a 29.97fps (60i) datastream. It SHOOTS at 60i, 30p, or 24p, but it has to do the "pulldown" to record it as a 60i stream .. which of course is then returned ot the shootign format in the editing software using "reverse pulldown".

:)

- Mikko
 
Haroon, I don't see why it is so important that you go 24p. 25p is soo close that many, many would be hard pressed to tell the difference.

I believe part of the reason for the lack of 24p in the PAL DVX is how to get recorded in a 50i transport stream. The pull down is where you run into problems.
 
doncamillo said:
If you want to output your master to film be happy you have a 25p (PAL) master as it has more resolution. The process of outputting to film is not 'seamless' anyway, so not an issue at all.

If you're outputting for TV, DVD or the internet you won't need a 24p master either.

By the way there is no special image/resolution loss because your outputting from 25p to film. The 25 frames you have recorded per second are just played back at 24fps. And the eye doesn't see the difference. The only real change is to the sound that is made to sync-up to the new frame-rate.

In Europe tons of films are shot in 25p and are shown in the cinemas at 24fps, no biggy. As long as 24p isn't needed your time is probably better spent on something else than converting the master you already have.
Click to expand...

At last the solution to my problems ... Actually I'm still a bit confused about the unconscious mind picking up the 1 additional frame going in every 1 sec. i.e. instead of 24fps its 25fps. Also, slowing down the sound to sync. with video changes the natural sound attributes e.g. pitch; hence causing bits and pieces of mind tension throughout the 24P (25P converted) footage.

Anyway I think I have to stick with this audience-psychological glitch as a curse of 25P which is affectively nullified by pull-down-less pure 25fps 720x576 higher quality SD footage :D
 
ncje said:
David Jimerson said:
24p is not ever "native 30p." The DVX shoots 24 progressive pictures per second (actually 23.976, but it's the same thing.)

When it shoots 30p, it's 29.97 progressive pictures per second.
Click to expand...

Actually - just to make it more confusing. When in 30p or 24p or 24pa mode the camera is always shooting in a 29.97 progressive stream and adding pulldown flags to the 24p/pa modes.
Click to expand...

No, that would indicate that the CCDs are being read at a rate of 29.97, progressive, and that's not the case except in 30p. In 60i, they're being read as 59.94 interlaced, and in 24p, they're being read at 23.976, progressive.

It's only the recording stream, as mikko says, which is 29.97 -- and it's actually 59.94 interlaced.
 
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