Framerate

Why is it important to know what frame rate you are working at?

It is important to know what frame rate you are working at as you need to know what platform you will be displaying it on such as TV and cinema. Along with this other countries use different standard frame rates for the TV. This means that the footage will need to be created to be able to be displayed on there standard TV.

Platform that it is playable on TV

  • UK – Pal (25fps)
  • USA – NTSC (30fps) – (29.97fps)
  • Film – everywhere use (24fps or 48fps)
  • Animation (24fps)
  • Games (60fps)

The more frames used per second used will allow for a smoother feel to the motion.

As defined by Wikipedia “Frame rate, also known as frame frequency, is the frequency (rate) at which an imaging device displays consecutive images called frames. The term applies equally to film and video cameras, computer graphics, and motion capture systems. Frame rate is usually expressed in frames per second (FPS)”. Information from https://en.wikipedia.org/wiki/Frame_rate

What are the benefits and drawbacks of having a really high frame rate?

A good example of Frame rate is slow motion, to get this they would have had to increase the fps to 250 when making the footage. Then in the post production stage they could play the video back at a lower frame rate achieving a slow motion effect. This works by playing the same number of frames back over a longer period of time:

e.g. 250 fps  = 250 images per second

Played back at 25fps = 250 images / 25 = 10 seconds

l0112_framerates

If the footage was filmed at 25fps to achieve this they would insert new frames as you are trying to stretch the existing number of frames over a longer time period. This is known as time-stretching or digital slow motion.

Time stretching

As defined by wikipedia “The second type of slow motion is achieved during post production. This is known as time-stretching or digital slow motion. This type of slow motion is achieved by inserting new frames in between frames that have actually been photographed. The effect is similar to overcranking as the actual motion occurs over a longer time.

Since the necessary frames were never photographed, new frames must be fabricated. Sometimes the new frames are simply repeats of the preceding frames but more often they are created by interpolating between frames. (Often this interpolation is effectively a short dissolve between still frames). Many complicated algorithms exist that can track motion between frames and generate intermediate frames that scene. It is similar to half-speed, and is not true slow-motion, but merely longer display of each frame”. Information from https://en.wikipedia.org/wiki/Slow_motion

The drawbacks of having a really high frame rate is will also have an effect on the file size, the more images used need to have more file space to be save on.

 

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