Exporting video files from Steam Game Recording doesn't work for me, so I make clips and use this to get an mp4 file instead.
$ cargo install --git=https://github.com/darkwater/steam-clip-exporter- Run
steam-clip-exporter - Select clip to export
ffmpegis used to glue the chunks together in a fraction of a second, no re-encoding- Path of output file is printed to stdout
Suggestion:
cp $(steam-clip-exporter) ./output.mp4(Better UX may come later)