M3U8 is a plain text playlist file format used by Apple's HTTP Live Streaming (HLS) protocol. It contains an ordered list of media segments (typically .ts files) that a media player can download and play sequentially to stream audio and video over the internet. The M3U8 file itself doesn't contain the actual media data; instead, it acts as an index or table of contents, pointing to the locations of the media segments. It can also include metadata such as stream information, encryption keys, and alternative streams with different bitrates, allowing for adaptive bitrate streaming. This enables the player to dynamically switch between different quality levels based on the user's network conditions, providing a smoother viewing experience. M3U8 files are widely used for streaming video content on various platforms, including websites, mobile apps, and smart TVs. They are essential for HLS, which is a dominant streaming protocol.