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A Question of Frame-rate

roblewis56's picture
Last seen: 3 days 22 hours ago
Joined: 06/07/2009 - 11:59pm

Some like to shoot at a high frame-rate such as 60fps, others like to use 24fps to get the "cine effect". I suggest here to shoot at the highest rate you can then produce to get the effect you want. I shot this video using the 1080/60p mode in my Panasonic HDC-HS700, but produced it as MPEG files at 15, 24, 30, and 60fps then combined them and produced the final product at 60fps. Director Douglas Trumbull, known for the visual effects in "2001: A Space Odyssey" and winner this year of a lifetime achievement Oscar is a champion of high frame-rates. He said of his earlier frame-rate experiments "When we shot test films at 24, 36, 48, 60, 66 and 72 frames a second, we didn't have words in English that describe the phenomenon. We immediately saw a profoundly different kind of experience happening up around 60 frames: The surface of the screen became like a window into reality." Judge for yourself which rate gives the effect you like the best. The subject is the noon AIKIDO practice in the Faculty Glade at the UC Berkeley.

http://www.youtube.com/watch?v=LetrWaR8kQc


Ian Kirkpatrick's picture
Last seen: 4 weeks 27 min ago
Joined: 07/06/2008 - 1:38am

There are a few different factors in play here.

If you shoot and replay at the same fps rate and they are movie film celluloid frames or progressive video frames, (not to be confused with interlaced scan rate) then the higher the frame rate the better, (within persistence of vision limits), and the end result will be better for two reasons. 1. Motion will be smoother because there will be less movement between frames, but more importantly, 2. Perceived picture quality will be better, for the same native image quality, because of the cumulative effect of more information being presented to the brain within a persistence of vision period.

With film based movies there was no choice but to playback at the same rate as shooting otherwise motion speed changed, but with digital video using the firmware in cameras or editing software available for computers just about any replay standard can be applied for a given shoot standard and this is where it all goes wrong.

Apart from the transcoding losses when changing video standards, unless the display device matches the frame rate of the video, or is a multiple of it, the benefits of one standard over the another may be lost. If you shoot, edit and export in 24p and then display on a TV or projector that adjusts its frame rate to 24p the "cine effect" will be preserved but if presented to a computer monitor, even at full screen HD, it won't look as good.

I learnt some years ago when first acquiring my Flash skills and building animated Flash video for web sites that there are sweet spots when it comes to frame rates. Dissatisfied with the smoothness of the animation achieved, I tried various frame rates and found 30fps was better that 40 or 50fps and it did not get better again until nearly 60fps because most computer monitors are 60Hz frame rate or 60p. Admittedly at the time I was also fighting processor speeds etc. These days it is much less of a problem.

For delivery at full HD to the web or older NTSC TV receivers, 30p or 60p will be best. Only if you can display at 24p (or 25p) can the full "cine effect" benefits of 24p be appreciated. Fortunately here in PAL land our HDTV frame rate is 25fps, usually displayed at 50 or 100Hz and the great majority of the receivers in the market are multi standard.


roblewis56's picture
Last seen: 3 days 22 hours ago
Joined: 06/07/2009 - 11:59pm

Thank you for your addition. As for 24p and the "cine effect" I think if your TV is 120Hz or higher it will display OK because 24 is a divisor of 120.

Robert