24p or 25p for film transfer? at DVinfo.net

Michael Chen · July 5th, 2005, 05:39 AM

Hi guys,

I have been getting contrasting view on this.
I have been adviced by the HD users in my country, which uses PAL, that we should shoot on 25p especially when working on a low budget due to the cost effectiveness during post.

On the other hand, i've been getting advice that I should go for 24p for a smooth film transfer.

I'm confused. Which is the better way assuming that we're working on a very tight budget?
Also, from researching the net, it has been stated that it will not be a problem transferring 25p to film as the movie will only be slowed down by 4%. Will it cause any noticeable difference with the 4% decrease in speed?

Hope that some advice can be given. Thanks.

Mathieu Ghekiere · July 5th, 2005, 05:45 AM

It won't be a noticable difference you just have to watch your sound.

Patrick Jenkins · July 5th, 2005, 12:56 PM

Either one is good. Get whichever fits your budget best!

Jon Fordham · July 5th, 2005, 06:11 PM

It's true that both frame rates will transfer to film just as easy as the other.

However, there are other issues to consider. My advice would be to use whatever standard your country uses. 24P if it's NTSC and 25P if it's PAL. If PAL is the standard used in your area, then I strongly suggest you use PAL. For two reasons... One, it will be ALOT easier to work with when it comes to integration of existing gear. And two, PAL has significantly higher vertical reason than NTSC. With 25P PAL you'll acheive 576 lines of vertical resolution compared to 480 lines of vertical resolution in NTSC.

Michael Chen · July 5th, 2005, 07:00 PM

Thanks for the feedback.
Guess I will go with 25p as adviced by most.

by the way, for transfer to film purpose, I read that the only thing we need to do when doing the transfer is to adjust the audio pitch, and slow down the whole movie by 4%... can anyone kind enough to explain how's the process like or where I can get a better description on what needs to be done?

One last question is, i read from DVfilm regarding the 20 minutes interval that we have to take note as the projector has to change the film reel every 20 minutes or so... what is the issue that we've to take note? i'm not so sure if I understand the no music/fade every 20 minutes part....

and thank you for helping me out. the first time is always the hardest.
but it's all getting clearer thanks to this forum.

Dominic Jones · July 11th, 2005, 10:19 AM

Hi Michael,

You don't need to slow the movie down by 4%, that is the effect of transferring 25p PAL source footage onto film, which runs at 24p.

You can think about it this way:
When projected on film, in one second 24 frames are shown. When it was shot, 25 fps were captured, so on playback after one second there is still a frame left over to be shown
This 25th frame will then get shown at the start of the next second of projection, followed by another 23 frames, leaving 2 frames left over from the original source material after 2 seconds, and so on for every second of the film...

So essentially the film will naturally run 1/25 (= 4%) slower than it will on a PAL TV set.

This is why you need to correct your audio pitch, as the slightly slower projection will cause the sound to have a lower pitch than intended.

To sum it up: All you need to do is pitch up your audio by 4% to maintain correct pitch for 24p playback, and you're good to go...

Kyle Ringin · July 11th, 2005, 05:02 PM

Before you go to too much effort to do this yourself, give the film transfer house a call as I think a lot of them like to do this themselves.

Stephen Duke · July 23rd, 2005, 09:07 AM

Doing a transfer for 25p will slow your movie done by a little over 4%, and your sound will drop close to a semi tone.

If you choose to shoot in 24p the be aware of your local electricity supply as it is known to cause a strobing / flicker effect on your video.

steve

Michael Chen · July 27th, 2005, 10:46 PM

thanks for the feedback so far. i've a clearer view now.

Will check them out with the transfer house.

Andrew Paul · September 5th, 2005, 11:52 PM

A lot of software will let you change audio duration and keep the pitch the same. I use Adobe Premiere and that will let you change the duration by % or time and gives you the option to maintain the pitch. A few mouse clicks, sit and wait and few seconds (minutes if its a big file) and your done.

July 5th, 2005, 05:39 AM	#1
Michael Chen Regular Crew Join Date: Apr 2002 Location: Singapore Posts: 163	24p or 25p for film transfer? Hi guys, I have been getting contrasting view on this. I have been adviced by the HD users in my country, which uses PAL, that we should shoot on 25p especially when working on a low budget due to the cost effectiveness during post. On the other hand, i've been getting advice that I should go for 24p for a smooth film transfer. I'm confused. Which is the better way assuming that we're working on a very tight budget? Also, from researching the net, it has been stated that it will not be a problem transferring 25p to film as the movie will only be slowed down by 4%. Will it cause any noticeable difference with the 4% decrease in speed? Hope that some advice can be given. Thanks.

July 5th, 2005, 12:56 PM	#3
Patrick Jenkins Major Player Join Date: Sep 2004 Location: Maryland, USA Posts: 382	Either one is good. Get whichever fits your budget best! __________________ PAL shooter in NTSC territory

July 5th, 2005, 06:11 PM	#4
Jon Fordham Major Player Join Date: Sep 2003 Location: New York, NY Posts: 242	It's true that both frame rates will transfer to film just as easy as the other. However, there are other issues to consider. My advice would be to use whatever standard your country uses. 24P if it's NTSC and 25P if it's PAL. If PAL is the standard used in your area, then I strongly suggest you use PAL. For two reasons... One, it will be ALOT easier to work with when it comes to integration of existing gear. And two, PAL has significantly higher vertical reason than NTSC. With 25P PAL you'll acheive 576 lines of vertical resolution compared to 480 lines of vertical resolution in NTSC. __________________ Jon Fordham Director of Photography www.jonfordham.com

July 5th, 2005, 05:45 AM	#2
Mathieu Ghekiere Inner Circle Join Date: Jun 2004 Location: Belgium Posts: 2,195	It won't be a noticable difference you just have to watch your sound.

July 5th, 2005, 07:00 PM	#5
Michael Chen Regular Crew Join Date: Apr 2002 Location: Singapore Posts: 163	Thanks for the feedback. Guess I will go with 25p as adviced by most. by the way, for transfer to film purpose, I read that the only thing we need to do when doing the transfer is to adjust the audio pitch, and slow down the whole movie by 4%... can anyone kind enough to explain how's the process like or where I can get a better description on what needs to be done? One last question is, i read from DVfilm regarding the 20 minutes interval that we have to take note as the projector has to change the film reel every 20 minutes or so... what is the issue that we've to take note? i'm not so sure if I understand the no music/fade every 20 minutes part.... and thank you for helping me out. the first time is always the hardest. but it's all getting clearer thanks to this forum.

July 11th, 2005, 10:19 AM	#6
Dominic Jones Major Player Join Date: Mar 2005 Location: Brighton, England Posts: 225	Hi Michael, You don't need to slow the movie down by 4%, that is the effect of transferring 25p PAL source footage onto film, which runs at 24p. You can think about it this way: When projected on film, in one second 24 frames are shown. When it was shot, 25 fps were captured, so on playback after one second there is still a frame left over to be shown This 25th frame will then get shown at the start of the next second of projection, followed by another 23 frames, leaving 2 frames left over from the original source material after 2 seconds, and so on for every second of the film... So essentially the film will naturally run 1/25 (= 4%) slower than it will on a PAL TV set. This is why you need to correct your audio pitch, as the slightly slower projection will cause the sound to have a lower pitch than intended. To sum it up: All you need to do is pitch up your audio by 4% to maintain correct pitch for 24p playback, and you're good to go...

July 11th, 2005, 05:02 PM	#7
Kyle Ringin Major Player Join Date: Oct 2004 Location: Melbourne, Australia Posts: 241	Before you go to too much effort to do this yourself, give the film transfer house a call as I think a lot of them like to do this themselves.

July 23rd, 2005, 09:07 AM	#8
Stephen Duke Booth Monkey Join Date: Jan 2004 Location: New York Posts: 30	Doing a transfer for 25p will slow your movie done by a little over 4%, and your sound will drop close to a semi tone. If you choose to shoot in 24p the be aware of your local electricity supply as it is known to cause a strobing / flicker effect on your video. steve

July 27th, 2005, 10:46 PM	#9
Michael Chen Regular Crew Join Date: Apr 2002 Location: Singapore Posts: 163	thanks for the feedback so far. i've a clearer view now. Will check them out with the transfer house.

September 5th, 2005, 11:52 PM	#10
Andrew Paul Regular Crew Join Date: May 2004 Location: UK Posts: 130	A lot of software will let you change audio duration and keep the pitch the same. I use Adobe Premiere and that will let you change the duration by % or time and gives you the option to maintain the pitch. A few mouse clicks, sit and wait and few seconds (minutes if its a big file) and your done.