1. download http://ffmpeg.zeranoe.com/builds/ (Static file, your bit)
2. go into the ffmpeg file folder (wherever you downloaded it) and load ff-prompt
3. right click and paste the following into the command window
ffmpeg -i [YOUR GIF NAME].gif -c:v libvpx -crf 32 -b:v [BITRATE] -an [OUTPUT FILE].webm

[YOUR GIF NAME] -> Gif location on your computer, best to put it at C:\. Example -> C:\GIF
[BITRATE] -> Bitrate of the recording, I keep at at 300k. Example -> 300k
[OUTPUT FILE] -> What the file will be saved as, saved to (Download Location)\bin. Example -> WebmGif

Example -> ffmpeg -i c:\GIF.gif -c:v libvpx -crf 32 -b:v 300k -an webmgif.webm