MPEG-4 Part 17, or MPEG-4 Timed Text (MP4TT), or MPEG-4 Streaming text format is the text-based

subtitle Subtitles are texts representing the contents of the audio in a film, television show, opera or other audiovisual media. Subtitles might provide a transcription or translation of spoken dialogue. Although naming conventions can vary, caption ...

format for

MPEG-4 MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related ...

, published as

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

IEC The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronic and related technologies. IEC standards cover a vast range of ...

14496-17 in 2006. It was developed in response to the need for a generic method for coding of text as one of the multimedia components within audiovisual presentations. It is also streamable, which was one of the main aspects when creating the format. It is mainly aimed for use in the .mp4 container, but can also be used in the .3gp container as 3GPP Timed Text (TTXT), which is technically almost identical with .mp4 but more used in

cell phone A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This radio ...

s. 3GPP Timed Text is exactly the same as MPEG-4 Timed Text when used in the .mp4 container. It can be also used in other file formats based on the

ISO base media file format The ISO base media file format (ISOBMFF) is a container file format that defines a general structure for files that contain time-based multimedia data such as video and audio. It is standardized in ISO/ IEC 14496-12, a.k.a. MPEG-4 Part 12, and w ...

3GPP The 3rd Generation Partnership Project (3GPP) is an umbrella term for a number of standards organizations which develop protocols for mobile telecommunications. Its best known work is the development and maintenance of: * GSM and related 2G and ...

approved the Timed text format for 3G multimedia services in 3GPP TS 26.245 in 2004. MPEG-4 Part 17 (ISO/IEC 14496-17:2006) defined ''Text Streams'' that are capable of carrying 3GPP Timed Text. For 3GPP text streams, ISO/IEC 14496-17:2006 defined a generic framing structure suitable for transport of 3GPP text streams across a variety of networks ( RTP and

MPEG transport stream MPEG transport stream (MPEG-TS, MTS) or simply transport stream (TS) is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol (PSIP) data. It is used in broadcast syst ...

and

MPEG program stream Program stream (PS or MPEG-PS) is a container format (digital), container format for multiplexing digital audio, video and more. The PS format is specified in MPEG-1 Part 1 (ISO/IEC 11172-1) and MPEG-2 Part 1, Systems (ISO/IEC standard 13818-1/ITU ...

). The framing structure for text streams consists of so-called Timed Text Units (TTU).

Supporting implementations

QuickTime Pro and MP4Box can create or produce these subtitle streams out of various subtitle input formats. MP4Box uses the

FourCC A FourCC ("four-character code") is a sequence of four bytes (typically ASCII) used to uniquely identify data formats. It originated from the OSType or ResType metadata system used in classic Mac OS and was adopted for the Amiga/Electronic Arts ...

tx3g for MPEG-4 Timed Text because of its inherently higher compatibility. MPEG-4 Timed Text is heavily based on

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing data. It defines a set of rules for encoding electronic document, documents in a format that is both human-readable and Machine-r ...

semantics. On October 7, 2005,

VideoLAN VideoLAN is a Nonprofit organization, non-profit organization which software development, develops software for playing video and other media formats. It originally developed two computer program, programs for media streaming media, streaming, ...

added decoding support for MPEG-4 Timed Text subtitles in

VLC VLC may refer to: * Variable-length code, a code which maps source symbols to a variable number of bits * The Very Light Car, prototype vehicle * Visible light communication, a communications medium using fluorescent bulbs or LEDs * Victorian Landc ...

. On October 30, 2005,

Gabest Media Player Classic (MPC), Media Player Classic - Home Cinema (MPC-HC), and Media Player Classic - Black Edition (MPC-BE) are a family of free and open-source, compact, lightweight, and customizable media players for 32- and 64-bit Microsoft Win ...

added decoding support for MPEG-4 Timed Text subtitles in

MPC MPC, Mpc or mpc may refer to: Astronomy * Megaparsec (Mpc), unit of length used in astronomy * Minor Planet Center, Smithsonian Astrophysical Observatory ** ''Minor Planet Circulars'' (MPC, M.P.C. or MPCs), astronomical publication from the Minor ...

References

External links

GPAC MP4Box explanation of 3GPP Timed TextOfficial MPEG web site
XML-based standards Markup languages Text codecs Subtitle file formats MPEG-4 {{standard-stub

Supporting implementations

See also

References

External links