Subtitles, Captions, WebVTT, HLS, and those magic flags 🤔

The article discusses subtitles and captions in streaming video, their differences, types of captions, and how they work in Mux Video. It explains that there are two ways to carry captions - in-band and out-of-band. In-band captions are contained within the video stream while out-of-band captions are delivered separately from the video stream. The article also talks about various formats for delivering closed captions and subtitles files on the internet, such as SRT, TTML, and WebVTT. It mentions that Mux Video currently delivers all its video over Apple HTTP Live Streaming protocol (HLS) and supports WebVTT format. The article concludes by discussing the mysterious three flags - AUTOSELECT, DEFAULT, and FORCED - used in HLS manifests for captions and subtitles.