Gordon Monro - "Rainbow Snake Dry River"

"Rainbow Snake Dry River"

Video transferred to DVD, with stereo sound, duration 12 mins (video 1998, audio 1995)

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Australia Licence.

Program note

The sound track

The sound track for Rainbow Snake Dry River is a piece of music called Dry Rivers, which is a computer-generated work consisting of fractal waveforms.

Dry Rivers was inspired by a trip the composer took through the Western part of New South Wales, Australia. The country is semi-arid rather than desert, being covered by low scrub. It is very flat, and changes imperceptibly over hundreds of kilometres. Every river we came to, except the Darling, was dry.

There are nine parallel lines of sound in Dry Rivers, each with a different sub-audio frequency (the slowest repeating every 6 seconds). However, the fractal waveforms are sufficiently complex to allow each cycle to be heard as a distinct sound. The timbres of the waveforms change slowly throughout the piece.

The nine lines consist of "phrases" arranged in a simple fractal-like manner. The dual use of fractals at the waveform level and at the phrasal level helps to give the impression of something that is always the same, yet always changing.

The visual part

The visual part for Rainbow Snake Dry River was derived from the soundfile of Dry Rivers. A three-dimensional image can be obtained from a sound, as follows. Take the x coordinate to be the value of the sound at a particular time, the y coordinate the value 1/100 of a second later, and the z coordinate the value 1/100 of a second later still. As we move through the sound file, this process builds up a complex three-dimensional image. If we add in time as a fourth dimension, we obtain a long "snake" in four dimensions.

The "snake" was given colours according to a process derived from the phrases in the sound track; the result is a Rainbow Snake in four dimensions. The video consists of various three-dimensional views of the Rainbow Snake, proceeding roughly in parallel with the sound, but sometimes slowing down to look at detail, and sometimes speeding to catch up.

Some images from the video

Please click on the small images below for enlarged versions.

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Performances, etc

Historical note

I had thought that this piece was irrecoverable, but in April 2005 I managed to get it onto DVD. The video was originally only 320 x 240, and was made in MPEG-1 format (the only codec I had in 1998). I had to generate and compress the frames in batches, as they would not all fit in the available hard drive space. My computer could only play MPEG-1 video at half-speed, which made it difficult to get an idea of the final result. (It was assembled on someone else's machine.) Since 1998, I have acquired a much more powerful computer, and spent a lot more money on software.

Looking back, the technical issues are not the problem with this piece. The original idea did not work as well as it might have, so I made up various ways of playing with the video. But these don't relate to the structure of the piece.