Oxalis leaf-opening time-lapse

I decided to take a time lapse video of my Oxalis plant's leaves unfurling in the morning. This was a good decision! Let's see if the video (30 MB) shows up properly here:

If you have a big monitor, I recommend full-screening. It's 1920x1080 pixels.

This is probably Oxalis triangularis; the seeds or roots happened to be present in the dirt I was using to pot up another plant. The leaves perform this unfurling every morning (I think triggered by both light and schedule) and then close back up after the lights are out. The flash of light you see in the beginning of the video is me turning on the lights and opening the curtains. There's a delay before the plant responds, and after all the leaves are open you can see some of the stalks jockeying around to get a sunnier spot. Plants are doing this sort of movement all the time. It's hard to notice because of the timescales.

I had meant to take a series of time lapse photos, but accidentally took a 2 hour 18 minute video. The following was supposed to speed up the video by 400x, but instead is about 160x. I don't really know how to adjust frame dropping in ffmpeg, so I just fiddled until I got something I liked:

#!/bin/bash

# The video was in 2 GB chunks in the `raw/` subdirectory, so I first had to
# put the filenames in order, then make a "join-file" for concatenation:
ls -1 raw | sed 's/^/file raw\//' > join.txt
# The audio was pointless noise, so I stripped it out:
ffmpeg -f concat -i join.txt -c copy -an joined-quiet.mp4
# Time lapse, with incorrect output filename:
ffmpeg -r:v 4800/1 -i joined-quiet.mp4 -r:v 12/1 sped-up-400x.mp4

What I ended up with is a 30 MB H264 video, 1920x1080 (pretty big). I could have smashed it down farther (got it down to 10 MB in one trial with HEVC), but I don't know much about browser support for various video formats, so I left it alone. Much better than the 16 GB source video in any event!


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