HTTP Live Streaming - Wikipedia
Fleeting- External reference: https://en.wikipedia.org/wiki/HTTP_Live_Streaming
The playlist is important. Only fething the .ts segment files and concatenating them will result in a glitchy video. The playlist say when to play what segment.
To convert this format to a webm, you first need to download all the ts files, then edit the playlist to point to them locally and then ffmpeg will be able to deal with it.
ffmpeg -i “playlist.m3u8” -c copy “new_file.mp4”