How can I make long timelapses?

As EO Browser timelapse functionality has a limit of processing up to 300 images at once, we need to do some post-processing, to be able to create longer timelapses. This can be especially useful with data collections like MODIS, with data available all the way back to the year 2000. Take a look at this MODIS timelapse of the Aral sea, dating from 2002 to 2019.

First, use command prompt to convert .gif timelapses from EO Browser into .mp4 files and then merge them together. For example, if we want to create an 18 years long timelapse, six timelapses, each three years long, are required. You should first download your smaller timelapses from EO Browser.

After downloading the gifs from EO Browser, we should transform them into .mp4 files. To do so, we first need to download and install ffmpeg program for making videos. Follow this tutorial to install ffmpeg.

To test if ffmpeg is installed, go to CMD and type: ffmpeg -version.

To transform a gif into mp4, first navigate to the folder where your gif files are stored, then open your command prompt and write in the following code:

ffmpeg -i GIF1.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" GIF1vid.mp4

The only part of the code you need to change is the name of your gif at the start and the name of the output .mp4 video at the end.

You need to transform all your .gif timelapses into separate .mp4 files:

ffmpeg -i GIF1.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" GIF1vid.mp4<br>
ffmpeg -i GIF2.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" GIF2vid.mp4<br>
ffmpeg -i GIF3.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" GIF3vid.mp4

Finally, merge all the .mp4 files into a final .mp4 file with the following code:

ffmpeg -i GIF1vid.mp4 -i GIF2vid.mp4 -i GIF3vid.mp4 -filter_complex "[0:0] [1:0] [2:0] concat=n=3:v=1:a=0" FinalVideo.mp4

In this code, we specify the output name of the final .mp4 timelapse and list the .mp4 files we want to merge. We preface the .mp4 files with -i. Then we need to add as many arrays, as there are input .mp4 videos; [0:0] for the first one, [0:1] for the second one, [0:3] for the third one and so on. The n=3 indicates how many input .mp4 files there are.

For 6 input .mp4 files, the code would look like this:

ffmpeg -i GIF1vid.mp4 -i GIF2vid.mp4 -i GIF3vid.mp4 -i GIF4vid.mp4 -i GIF5vid.mp4 -i GIF6vid.mp4 - filter_complex "[0:0][1:0][2:0][3:0][4:0][5:0] concat=n=6:v=1:a=0" FinalVideo.mp4