28 December 2006

Frame Rates

Let's hit the ground running, so to speak.

This afternoon I was hanging out with the Vasulkas and we were discussing video frame rates. Basically most of us have to choose between 24, 25, or 29.97 frames per second. While these frame rates allow us the persistence of vision necessary to perceive motion, it is interesting to think about the potential of high-speed video to produce other perceptual effects.

Steina said she believed that higher (read much higher) frame rates might actually trick the brain into forgetting that the images we see are video. Perhaps create an immersive cinematic image so realistic that the brain would no longer be able to discriminate between it and reality.

Yet naturally just as there is a low end on the perceptual threshold of movement in video (two frames) there is probably also a high end. Is it 50 fps (frames per second) 100 fps, or is it way up there in the tens of thousands like audio? My guess is its somewhere below 100 fps.

Economic forces have kept us from being able to experiment with high-speed video. High-speed film has the problem that just a couple seconds takes up valuable physical space and expensive resources (film stock). Yet in today's world of relatively affordable gigabyte harddrives, the prospect of storing high-speed video is not so intimidating. Perhaps the bottleneck today is the processors and video cards we would need to playback such higher frame rate material. Ideally we would have dedicated high-speed hardware and software.

Film sound is standardized at 48,000 Hz sample rate. This means that audio is sampled forty-eight thousand times per second! And yet for video we only "sample" our images at 25 frames per second (for the sake of simplicity I will assume the PAL frame rate). When you get down to 1/25 of a second there can still be an abundance of variation and movement in sound, yet you have only a still image.

Here we have the audio information from 1/25 of a second. Seems like a lot of variation right? At this duration we get a rumbling dirty wave pattern. If we go to the smallest grain of audio we end up with a pure high-pitched tone. These fluctuations in sound are interesting. So interesting, in fact, that granular synthesis is a very popular method of contemporary electronic music composition.

Think about what Martin Arnold might have done if he had had higher frame rates. While you are pondering this, enjoy this little clip of one of my favorite things he did, despite these arbitrary limitations:

5 comments:

Philipp said...

Well, concerning the framerate, I am not sure that it has such a big impact as there are/were experiments with high framerates. I think i remember that the Imax people had several nextgen cinema experiments running one of which used a higher framerate.
You could also compare that to computer games which are running at higher framerates most of the time.
Maybe computer games are not a bad place to start thinking about non-traditional not narrative ways of communicating.

Gabriel said...

I definitely want to learn more about what is already out there. I would like to know what the IMAX people concluded about higher frame rates. I am most interested in the prospect of movement during milisecond durations.

Video games are an excellent starting point for quantum narrative. Would you like to make a post about your thoughts on that?

Philipp said...

Sure. I'll have to do some research, but I think David Brabens 'Elite' would be a good starting point.

Gabriel said...

I looked up Elite and it seems pretty classic. Is the game engine the part which interests you? Do you think that Braben reached some kind of diversity threshold with 256 planets?

Philipp said...

Well, he reached the memory limitations of the time with his 256 planets. The sequel had another 256 Planets. ;-)

But seriously: There was no story - the audience made up theyre own adventure and the exitement came through exploring a coherent universe despite all the severe technical limitations on realism.
In other words you could say that Elite Provided a quantumspace of possible adventures, that although unpredictable formed a closed storyline formed in the minds of the audience.