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

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

IEC The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...

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 MPEG-4 Part 14 or MP4 is a digital multimedia container format most commonly used to store video and audio, but it can also be used to store other data such as subtitles and still images. Like most modern container formats, it allows streami ...

container, but can also be used in the

.3gp 3GP (3GPP file format) is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services. It is used on 3G mobile phones but can also be played on some 2G and 4G phones. 3G2 (3GPP2 ...

container as 3GPP Timed Text (TTXT), which is technically almost identical with .mp4 but more used in cell phones. 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 wa ...

. 3GPP 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 and

MPEG program stream Program stream (PS or MPEG-PS) is a 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-T H.222.0). The MPEG-2 ...

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

Supporting implementations

QuickTime Pro and

MP4Box GPAC Project on Advanced Content (GPAC, a recursive acronym) is an implementation of the MPEG-4 Systems standard written in ANSI C. GPAC provides tools for media playback, vector graphics and 3D rendering, MPEG-4 authoring and distribution. GP ...

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 I ...

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 arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable ...

semantics. On October 7, 2005,

VideoLAN VideoLAN is a non-profit organization which develops software for playing video and other media formats. It originally developed two programs for media streaming, VideoLAN Client (VLC) and VideoLAN Server (VLS), but most of the features of VLS ...

added decoding support for MPEG-4 Timed Text subtitles in VLC. 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-bit and 64-bit Microsof ...

added decoding support for MPEG-4 Timed Text subtitles in MPC.

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