Working on web standards often means thinking about tons of different edge cases of how a new feature might be used. Sometimes the only way to find them is to just start poking at the API yourself: trying weird inputs, seeing what happens, and paying attention when something doesn’t look quite right. Once in a while, that leads somewhere unexpected.

At Demuxed 2025, I presented streamrr, a small Rust tool that records an HLS stream (playlists, segments and all) and replays it later, exactly as it happened. Watch the talk below, or read on to find out how it works under the hood.

At Demuxed 2023, I came back with a sequel: I took baby’s first HTML5 <video> element and taught it to play video (and audio) backwards, frame by frame. Watch the talk below, or read on to find out how it works.