ISO/IEC 14496-30:2018 This document describes the carriage of some forms of timed text and subtitle streams in files based on ISO/IEC 14496-12 (the ISO base media file format). The documentation of these forms does not preclude other definition of carriage of timed text or subtitles, see, for example, 3GPP Timed Text (3GPP TS 26.245), or the carriage of captioning information embedded in a media stream of another type (see Annex A).