Unclear on 29.97 and 30 Frames Per Second

CLINT-DANBURY wrote on 9/20/2021, 6:11 PM

What do I need to know about ?...

29.97 Frames per second
(And)
30 Frames per second

I searched this forum for info on those two numbers and found a bunch of posts about Apple iPhones.

Duh

I hope I'm not junking up the forums with clueless newbee ignorance; it's just that you guys actually help the brain cells work.

My questions on this are all about screen capture and importing.

To the clueless newbee (i.e., me) these two options look like a ridiculous set of choices.

(e.g., Why not also have a choice for 14.985 Frames per second ?)

Can somebody tell me what gives with these two just barely different speeds ?

More to the point, which one do I choose under what circumstances ?

===================

Using...

Movie Studio 18 Platinum

Version: 18.1.0.24

Comments

ericlnz wrote on 9/20/2021, 6:41 PM

The answer is basically historical. 29.97 is the NTSC TV system framerate for the USA and countries that use NTSC. The UK and many other countries use the PAL system which is 25 fps.

Then along came digital and phones that take video. The phone manufacturers aren't involved with TV production so use a sensible framerate, usually 30.

Often 29.97 is referred to as 30 and most of the time when editing the numbers are interchangeable. As to which to use it depends on your final output. If you are burning a DVD or Blu-ray usually 29.97 as this framerate fits the relevant disc specifications. But if it's just a file to play on your PC, or TV from a usb drive use 30.

As to why no 14.985? It's because such a framerate has never been a standard for anything.

CubeAce wrote on 9/20/2021, 7:05 PM

@CLINT-DANBURY

Hi Clint.

In the early days of analog TV it was easiest to sync frame rate to the mains frequency, so in a few countries that was 60fps and the rest of the world it was 50fps. Film through projectors at the cinema has always remained 24 fps.

When Colour was first introduced, few people had colour sets and were still viewing on black and white receivers.

Saturated colour on a black and white set made for crawling dots of pure white on such sets and it was found that if the recording was made at 0.1% slower than the broadcast frame rate that the unwanted effect on the B&W TVs was reduced even though the frames were still broadcast at the full frame rate. the lower 29.97 frame rate was put on video tape cameras for interlacing of the 59.49 frame rate which was basically a mistake as the interlacing depended on having 60 frames per second.

Either way the broadcasts were always at the full frame rate of the local mains frequency and a 59.49 frame rate video will (or should) be played back at 60fps. Higher frame rates are meant for smoother playback of slow motion sequences.

People who game play like to record at the frame rate they see their game played at, so such screen recorders vary their frame rate, sometimes many times higher than intended for broadcast or normal internet playback via a web hosting platform, but such 'recordings' are not normally suitable for video editing production.

Ray.

CLINT-DANBURY wrote on 9/21/2021, 2:43 AM

@ericlnz, @CubeAce,

------------------------------

Thanks, both of you; once again, useful info for the brain.

This has been quite a lesson in scientific history; Wow; you'd think they were trying to create obfuscation on purpose.

Anyway, as to what yall mentioned, these "movies" will be clips of three to five minutes, and maybe a few ten minute clips.

They are going to be mostly - if - not - totally screen caps of software and how to use it, and will be distributed (hopefully totally) via the internet.

I guess I'll ask the intermediary kids what frame rate to use.

Thanks a ton.

CubeAce wrote on 9/21/2021, 4:38 AM

@CLINT-DANBURY

Hi Clint.

For that I would personally stick to average the screen refresh rate of 60fps. That should satisfy the majority as if you are capturing screen usage, there is no 'exposure time' as such for each frame, so in theory should provide smoother graphics for movement of the mouse etc. Going above that is not really an option for video editing even is some capture software can do more frames per second to keep up with higher refresh rate monitors.

Ray.

browj2 wrote on 9/21/2021, 7:34 AM

@CLINT-DANBURY

Hi Clint,

I use the easy method. In NTSC land, my project settings and export settings are the same - 29.97 fps. I know that the export will work everywhere.

In my tutorials, I use the same settings, but the screen captures are all at 30 fps. I use a separate screen capture program with 3 settings - 15, 25 and 30 fps. The clips get adjusted automatically by the program.

John CB

CLINT-DANBURY wrote on 9/22/2021, 12:14 AM

Hi guys, mucho thanks for the help. I just traded a "chat" session with the powers that be. They tell me...

Acceptable: 25 to 60 FPS
Then on their side, all outputs are resampled to 30 FPS
So, my best guess: Use 30

browj2 wrote on 9/22/2021, 9:02 AM

@CLINT-DANBURY

Hi Clint,

That removes any question. Always try to use the same project settings as the required output, so use 30.

John CB