F4M

F4M is a designation used in multiple contexts, but most commonly it refers to the file extension .f4m used for Adobe HTTP Dynamic Streaming manifests. A .f4m file contains a manifest that lists available video renditions, their bitrates, and the URLs of media segments. The manifest is consumed by players to perform adaptive streaming by selecting and requesting the appropriate segments based on network conditions. The F4M/HDS ecosystem was introduced by Adobe and was used with Flash-based delivery. As Flash declined, HDS and the use of .f4m manifests contracted in favor of HLS and MPEG-DASH. Nevertheless, some legacy systems, streaming servers, and certain players may still serve or require .f4m manifests, especially for backward-compatible content.

Other uses: In unrelated contexts, F4M can be an acronym or code within project names or databases. It is not associated with a single standardized definition beyond the HDS manifest usage, and the intended meaning is typically determined by surrounding documentation or context.

See also: Adobe HTTP Dynamic Streaming, Flash Media Server, HLS, MPEG-DASH.