Extended GK-2A Animations
The current videos on the GK-2A Latest Videos page are generated once every ten minutes as each new full disc infra red image has been received.
There is just under ten minutes which is enough, just, on a Raspberry Pi to perform the Sanchez processing create the false colour images and then to generate the animations for raw and Sanchez processed images over the last 24 hours and the last 5 days.
Having now captured data over 43 days, I wanted to see a full animation of the full data set, but trying to create this on a Raspberry Pi is not a great idea as whilst it is amazing for doing small processing tasks it really doesn’t match the processing power of a desktop PC.
There are some frames which show a bit of flicker with these being where only a partial frame has been downloaded or there are some missing frames which did not get downloaded correctly. Plus every so often GK-2A will split a full frame over two frames, which is an issue at the satellite end.
So to generate the full data set video, I first copied over all the image data from the Raspberry Pi, which is about 600MB of data per day (I’d been doing this every few days).
Since I’m running Windows 10 as my main desktop OS, I thought I’d experiment using the Windows Subsystem for Linux 2 which allows you to run Linux within Windows, utilizing a real Linux kernel. This meant that I could do the video generation with a slightly modified version of the code that I was using on the Pi which is a Python script, using ffmpeg.
Whilst ffmpeg does have a Windows version, the Linux one has the ability to take as a parameter a text file which contains a list of all the frames that the video is to be built from. This is straightforward to generate using Python using the glob library.
Having created the raw infra red version, I then kicked off the Sanchez processed version to show the processed version where the image is in full colour using an underlay.
This one doesn’t look, yet, quite as good with a degree of flicker. I’m still working to understand quite where this is coming in.
