Chapter 1: Frame Rate

All videos are made up from a sequence of still images - like photos - played very quickly. Your brain is fooled into filling in the gaps and thinks it is seeing real movement.

If we show 15 still pictures per second, we call that 15 Frames per Second (fps). That's actually about the rate that our brain works, so a video has to be at least 15fps in order to fool your brain into thinking it is real movement. Anything filmed below that (like some mobile phone footage) looks choppy and rubbish because it can be as low as 8fps.

Interestingly, pigeons see the world at 250 frames per second - which is why they are so quick at dodging cars!

TVs and DVDs in the UK normally use the PAL format, which displays video at 25fps. In the US, however, NTSC is used instead. This format displays video at 30fps (actually 29.97, but most people refer to it as 30). Both of these formats are thought of as Standard Definition TeleVision (SDTV).

High Definition TeleVision (HDTV) is a much newer format that is used in both the US and the UK. HDTV videos can be set at 25fps or 30fps as well as 50fps or 60fps - depending on what is needed.

Finally, cinemas use a different frame rate, just to keep things complicated. The actual frame rate is 23.976fps - but people quite sensibly call it 24fps most of the time.

If you film your video at 25fps, but play it at 30fps then either your video will speed up or you will have to play some of your frames twice in order to make it fit!

Reproduced with kind permission from Mark Clarkson, from the originial source

Photo: CC Suren