(registered 2019-10-14, last updated 2019-10-14) Type name: text Subtype name: vtt Required parameters: N/A Optional parameters: N/A Encoding considerations: 8bit (always UTF-8) Security considerations: Text track files themselves pose no immediate risk unless sensitive information is included within the data. Implementations, however, are required to follow specific rules when processing text tracks, to ensure that certain origin-based restrictions are honored. Failure to correctly implement these rules can result in information leakage, cross-site scripting attacks, and the like. Interoperability considerations: Rules for processing both conforming and non-conforming content are defined in this specification. Published specification: This document is the relevant specification. Applications that use this media type: Web browsers and other video players. Additional information: Magic number(s): WebVTT files all begin with one of the following byte sequences (where "EOF" means the end of the file): EF BB BF 57 45 42 56 54 54 0A EF BB BF 57 45 42 56 54 54 0D EF BB BF 57 45 42 56 54 54 20 EF BB BF 57 45 42 56 54 54 09 EF BB BF 57 45 42 56 54 54 EOF 57 45 42 56 54 54 0A 57 45 42 56 54 54 0D 57 45 42 56 54 54 20 57 45 42 56 54 54 09 57 45 42 56 54 54 EOF (An optional UTF-8 BOM, the ASCII string "WEBVTT", and finally a space, tab, line break, or the end of the file.) File extension(s): "vtt" Macintosh file type code(s): No specific Macintosh file type codes are recommended for this type. Person & email address to contact for further information: Silvia Pfeiffer Intended usage: Common Restrictions on usage: No restrictions apply. Authors: Silvia Pfeiffer , Simon Pieters , Philip Jägenstedt , Ian Hickson Change controller: W3C