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

subtitle Subtitles and captions are lines of dialogue or other text displayed at the bottom of the screen in films, television programs, video games or other visual media. They can be transcriptions of the screenplay, translations of it, or informati ...

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 tec ...

, published as ISO/ IEC 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 phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...

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. 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 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 systems ...

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

Supporting implementations

QuickTime Pro QuickTime is an extensible multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. Created in 1991, the latest Mac version, QuickTime X, is a ...

and MP4Box can create or produce these subtitle streams out of various subtitle input formats. MP4Box uses the fourcc tx3g for MPEG-4 Timed Text because of its inherently higher compatibility. MPEG-4 Timed Text is heavily based on XML semantics. On October 7, 2005, VideoLAN added decoding support for MPEG-4 Timed Text subtitles in VLC. On October 30, 2005, Gabest 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