24p vs 25p

E

etrust

Well-known member
Hi,

im using a Sony HDR-XR500. This cam is recording 25 frames per second.

I heard that to get really film look a cam should record 24.

Im able to convert 25p to 24p using premiere, vegas or after effects.

My question is:

Is there a diference if a cam is recording 24p or 25p and convert to 24p?

Can't wait for coments!!!
 
etrust said:
Hi, im using a Sony HDR-XR500. This cam is recording 25 frames per second. I heard that to get really film look a cam should record 24. Im able to convert 25p to 24p using premiere, vegas or after effects.
Click to expand...
The XR500 shoots 25 frames per second interlaced, it does not shoot 25p.

etrust said:
My question is: Is there a diference if a cam is recording 24p or 25p and convert to 24p?
Click to expand...
Is this a theoretical question? Because your camera does not shoot 25p. Visually, 24p and 25p look pretty much the same.

etrust said:
Can't wait for coments!!!
Click to expand...
Try google.
 
Hi,

oh sorry. yes my cam is capturing 25 frames per second interlaced. Good cams are recording 24p right?

my question is there a big diference betwenn 25 frames per second interlaced and 24p?

I heard that 24p are more film look style.

Please help me
 
I personally would always shoot in p (progressive) rather than i (interlaced) because progressive is the most similar way to the way in which film-stock captures light.

Progressive captures the whole image on the sensor for 1/50th of a second, whereas interlaced takes information from every even line of pixels, then goes back to the top and takes the information from the odd lines. This is all done at an extremely fast rate, so it still gives the same illusion of movement, though when placed side by side, progressive will be clearer and interlaced may appear to "flicker" on close examination.

24 fps will appear more film-like as this is the frame rate at which the film is passed through the gate, for 1/50th of a second. p is also closest to the way light exposes the film, as the entire "gate" (chip) receives all the light, records the entire image, then closes the shutter and moves on to the next frame. (In the case of digital the "shutter" is usually simulated, simply a case of not receiving the information sent by the chip)

As to whether slowing 25 fps to 24 fps in post makes a difference or makes it more film-like, I don't know, if anyone has tested this I would like to find out.
 
Hi,

thanks for all coments.

Could somebody answer this question:

If my cam record 25 frames per interlace and i convert with premiere to 24p.

Can i see a diference when somebody will make shots direct with 24p?

My sony hdr-xr500 is only possible to shot 25 :(

thank you
 
Just forget the difference between 24 and 25, OK? For most purposes, they are simply the same. Many PAL camcorders do not even have the 24p option and use 25p. The transfer between 24 film and 25 video is usually also done 1:1 (since most people will not notice the difference in speed).

What is important for the "movie look" is the "P" as in "reading the whole frame at once and not creating it from two interlaced fields". If your camera does not offer native progressive scan (and this is the case), you can try to fake it in post, but my opinion is that it will never be the same. This also applies to "frame mode" of some camcorders (like DVC30).

bottom line: Forget the difference between 24 and 25, focus on deinterlacing in post, do not expect miracles.
 
25 frames interlaced=50i.

50i looks nothing like 25p, it's motion is very smooth. Thankfully because 50 is a multiple of 25, simply discarding half the fields and doubling the rest will create 25 frames progressive which should give an identical look to 25p except there's a 50% vertical resolution loss. The tricky part is when you're trying to convert 60i to 24p.
 
Hi everybody,

very intresting..

How to fake it in post? suggestion from Warthog

Huy Vu where can i found a video to see the diference? Is there really a big deference?

So if i want the real film look i need a cam that shot 24p. Because it's not the same if i covert in a video editor tool from 1080i to 1080p right? :embarasse
 
etrust said:
How to fake it in post? suggestion from Warthog
Click to expand...
By de-interlacing 50i footage. You can just throw away odd or even fields and then stretch the result vertically (or shrink horizontally depending on your desired target size), or you can use one of the more advanced methods that might (or might not) give you better results for certain types of scene/motion.

http://www.100fps.com/

So if i want the real film look i need a cam that shot 24p. Because it's not the same if i covert in a video editor tool from 1080i to 1080p right? :embarasse
Click to expand...
Yes, but you can get decent 540p footage from 1080i :)
 
Hi,

Warthog, thank you for this great link, i will read everything at night!

Sorry for asking, but which way (tools and process) you exactly personaly use here:

"you can get decent 540p footage from 1080i :) "
 
etrust said:
Sorry for asking, but which way (tools and process) you exactly personaly use here:

"you can get decent 540p footage from 1080i :) "
Click to expand...

None. I work with progressive footage most of the time. When I have to deinterlace, it is ussually a piece of 1080i footage to be used in SD NTSC sequence. Then I simply use the built-in De-interlace filter in FCP/FCE. This filter does discard one field, but at the same time it scales the image up to keep the original size - it will not allow you to just drop one field.

I believe that ffmpeg suite contains a tool which can do deinterlacing by simply dropping one field. The resulting clip can then be resized in any NLE. Simple resize, while not very correct technically, can also give you reasonable results. It all depends on what quality you need.
 
hi everybody..

ok after reading and testing a lot here my reply. please correct me if im saying something wrong..

fact is: my cam is shoting 1080i.

1) i could deinterlace my footage using the default settings by using the tool virtualdub.

with this solution the movie seems to be smoother without these horrible lines.

Is my footage now 1080p?

Is there a difference if i deinterlace a footage using virtualdub or interpreting the footage on vegas or after effects as "upper field first" ? I could not see a diference.

2) I can read allways that for the cinema look the footage should be 24p.
I choose the option "frame rate conversion"convert to fps: 23.976 in virtualdub + deinterlace option.

After doing 2) wich format exactly i get?
Please tell me if I'm doing right.

Thank you
 
etrust said:
Hi,

Could somebody answer this question:

If my cam record 25 frames per interlace and i convert with premiere to 24p.

Can i see a diference when somebody will make shots direct with 24p?

My sony hdr-xr500 is only possible to shot 25 :(

thank you
Click to expand...

Yes there is huge difference,you will get twice amount of motion blur in frames because of 2 fields combined into one frame.So you have shutter 50 but it looks more like 25 with interlaced frames blended together.Too smooth and videoish.
I checked that with my camera,I only came close when capturing one field of interlaced footage but even then there was too much motion blur so you would need shutter 75 or higher.This cam is geting dust now anyway,i bought myself 24p cam.
 
Last edited:
You must log in or register to reply here.
Back
Top