How do I install FFMPEG inside Heroku?
Self answering as I had this problem and wish to share what I found:
Heroku supports ffmpeg as a buildpack to your app. Simply open you app settings at https://dashboard.heroku.com/apps/[app-name]/settings and scroll down to Buildpacks, where you should add https://github.com/jonathanong/heroku-buildpack-ffmpeg-latest.git to it.
Alternatively you can also run the CLI command:
$ heroku buildpacks:add https://github.com/jonathanong/heroku-buildpack-ffmpeg-latest.gitSource:
https://elements.heroku.com/buildpacks/jonathanong/heroku-buildpack-ffmpeg-latest