Information technology -- Coding of audio-visual objects -- Part 17: Streaming text format

ISO/IEC 14496-17:2006 was developed in response to the need for a generic method for coding of text at very low bitrate as one of the multimedia components within an audiovisual presentation. ISO/IEC 14496-17:2006 allows for example subtitles and Karaoke song texts to be coded and transported as separate text streams at bitrates that are sufficently low for use in mobile services over IP. Target applications are in particular found in areas with severe transmission bandwidth constraints, such as mobile services over IP. However, services over broadband IP, over broadcast channels and over optical media may also benefit from the low bandwidth of ISO/IEC 14496-17:2006 text streams.

ISO/IEC 14496-17:2006 specifies a text stream as a concatenation of text access units. A text access unit contains text information of a specific format. For each text stream, the format of the text information within the text access units is signalled. Each text access unit within a text stream is intended to be displayed at a specific instance in time. Note that ISO/IEC 14496-17:2006 signals the format of the text contained in text access units, but that it does not contain any text format specification