Mac – how to convert mp4 to webm

Command line utility ffmpeg can be used to convert mp4 video to webm format on Mac or Linux. Here are quick steps for Mac.

1. First we need to install ffmpeg with libvpx, libvorbis and fdk-aacc.

   $ brew install ffmpeg --with-libvpx --with-libvorbis --with-fdk-aacc
   

2. In case ffmpeg already installed without required libraries, you will have to unlink it and install it again

   $ brew unlink ffmpeg
   $ brew install ffmpeg --with-libvpx --with-libvorbis --with-fdk-aacc
   

3. Run ffmpeg on input-file.mp4 as shown below

   $ ffmpeg -i input-file.mp4 -c:v libvpx -crf 10 -b:v 1M -c:a libvorbis output-file.webm
   

   Note that this command may take a while. Once done, you should be able to see output-file.webm in current directory.