I have previously written about using FFmpeg to convert H264 into MP4, running in a Docker container.

Running desktop applications in Docker negates the need to install anything, and isolates processes more effectively than something like Brew would. I needed to use FFmpeg again this week, and so spent a little bit of time setting it up properly - using Docker. Jessie Frazelle wrote a post in 2015 named Containers on the Desktop that was the inspiration for doing this.

H264 is a codec. MP4 is a file container, which can contain H264. If you want to display H264 video on a web browser, it needs muxing into MP4 or another file container format.