Tuesday, May 24, 2011

67 Days of Spring

Earlier I used my Wingscapes PlantCam for several shorter time lapse projects. In this posting I present a two-month time lapse, from mid-March to mid-May, with the camera aimed into the woods in back of our house. You'll see daffodils bobbing up and down, a brief snowfall, and the greening of the woods from bottom to top (the forest floor always greens up first, and the tall trees leaf out last). When the weather switches from cloudy to sunny, there's a flash of light and moving shadows! Also, at around the 57 second mark, the invasive bush honeysuckle in the middle of the frame gets chopped down, giving you a better view into the woods beyond.

Now, some details. The camera took a picture every 30 minutes between 10AM and 3PM each day. Once I downloaded the photos and began constructing a video, I saw that the images whipped by much too fast; it would have been preferable to take a picture every 15 or even 10 minutes. Not willing to wait and try again in 2012, I used the interpolation techniques from the ZoomWalks to add intermediate frames. I also continued my research into encoding with ffmpeg, particularly with the complex (daunting) h264 encoder (the preferred format by most video hosting sites). After some Googling and experimentation, I created the video you saw with this command:
ffmpeg -f image2 -i ffr-%05d.jpg -vcodec libx264 -vpre hq -crf 24 -g 320 -threads 0 video-d.mp4

The file created this way was only 47MB, compared to 152MB using the original technique. It downloads much faster, but makes the computer CPU work a little harder to play the video. I hope I've achieved a good tradeoff. Note that you can always toggle between HD, high definition, and SD, standard definition, by clicking on the blue HD symbol on the playback bar. The default is HD playback.

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