How to convert Webm to Gif in Linux and resize the gif in Linux

how to

I use debian as my daily driver. Its a rock solid linux distribution. In the course of writing articles and howtos, I have had the need to record videos of my phone and post them. A video goes a long way to show and explain how a app works. Its better than writing a 1000 words. The videos that I record in my phone or emulator gets saved as a .webm file. These files are sometimes quite large and I wanted to

  • convert them to gif
  • scale them down to 50% of their original size. This also reduce their size.

I use two little nifty programs to do this - ffmpeg and gifsicle.

Installation

For debian based systems:

$ sudo apt intall ffmpeg gifsicle

Usage

Step 1 - convert the .webm file to .gif.

$ ffmpeg -y -i rec.webm -vf palettegen palette.png
$ ffmpeg -y -i rec.webm -i palette.png -filter_complex paletteus -r 10 out.gif

Here rec.webm is the recorded video. The first command creates a palette out of the webm file. The second command converts the webm file to gif using the created palette.

Step 2 - now that we have the gif, we will now scale it down to say 25%. This is how its done.

$ gifsicle --scale 0.25 out.gif -o scaled25.gif

Here out.gif is the output from the step 1. scaled25.gif is the final output.