mdk

Life is analog (is it?)

30 Jun 2005 » permalink

Today I started by making myself some test video material for furter timeline implementation testing. I was particularly interested if the sound doesn’t go out of sync with the audio, and if the timeline “cuts” at the excatly right moments. So I did what the old motion editors did with a felt pen:

I used Transcode to unpack the camcorder-captured AVI into individual frames and seperate audio. Than I used GIMP to actually draw the dot over the frames and Audacity to edit the sound. Than I packed it back to AVI with transcode again.

The blue bar below the frames is a small piece of sine wave that generates a nice beep for 1/25 of a second (yes, it’s PAL tv here). This way it lasts for excatly one frame. During the playback, if something is out of sync you can clearly see that the “beep” doesn’t sync with the dot flash.

The problem with all timelined video editing is, that there is no “smallest unit” thing. As long as you think about picture everything is fine — the basic unit is one single frame (be it 1/25th of a second or 1/30 of a second). You can’t cut in the middle of a frame.

But there is audio as well. Audio can start in the middle of a frame and can stop in the middle of a frame. Assuming the audio comes in a CD-quality, you get a basic unit of 1/44100th of a second (a single sample). That’s clearly not trackable so you do buffering. And once you do buffering things get compilcated.

That lead me to a thought how “analog” life actually is. In the digital world everything is a question of “sampling”. If you have audio sampled at 44100 samples per second you get a nice, smooth sound. If it’s only 11000 samples per sec, you can hear it’s “digital”, “jerky”, “not smooth”, “not fluent”. That applies to everything (video framerate, CRT displays refresh rate, CPU cycles…). On the other hand, we have the life itself, which seems to be “analog”. But is it?

When I move my hand,it seems there are no “samples” in the movement. It just moves smothly from one position to the other. Theoretically speaking, there is an infinite number of “points” where my hand can be on it’s (linear) way from one point to the other.

But if you think about atoms (or even smaller elements) that the hand is composed from… atoms can’t be just anywhere. They stick to a “grid” which is of a close-to-infinity resolution. But it surely isn’t infite. If you measure a linear distance between to arbitrary points in space, there is a finite number of positions where a single atom can exist. It’s all a matter of sampling, again.

Everything is digital. I might be wrong in this point though.