Thursday 11 July 2013


Things must be improving as I've set and reset the course record on a Strava segment through the wood this week. I admit that it was very slow and is still rather slow, but any hint of speed is progress.

A very fashionable zoom lens effect in the 1970's recreated to show just how fast I was going!
The photograph here was a little experiment to see if the 'zoom' effect could be recreated successfully from an mp4 movie. It seems it can. A movie was taken with a compact digital camera held firmly and the zoom moved from wide to tele. The movie was cropped to remove static frames and then each frame was extracted using FFMPEG. The 150 frames were recombined as layers in GIMP. The key thing was the order of layering. Neither wide-first nor tele-first worked. The optimum was to layer alternate frames in opposite directions, like so with the tele image as the 100% base layer (9 in this example):

1 8 3 6 5 4 7 2 9

Note how odd frames run one way and even the opposite. The transparency of each layer was set to 10%. I had to do the build-up manually as I couldn't find a package to do it.

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