H.324
Encyclopedia
H.324 is an ITU-T
recommendation for voice
, video
and data
transmission over regular analog phone
lines. It uses a regular 33,600 bit/s modem
for transmission, the H.263
codec for video encoding
and G.723.1
for audio.
H.324 standard is formally known as Terminal for low bit-rate multimedia communication. H.324 covers the technical requirements for very low bit-rate multimedia telephone terminals operating over the General Switched Telephone Network (GSTN). H.324 terminals provide real-time video, audio, or data, or any combination, between two multimedia telephone terminals over a GSTN voice band network connection.
H.324 terminals offering audio communication shall support the G.723.1 audio codec. H.324 terminals offering video communication shall support the H.263 and H.261
video codecs.
G.722.1
may be used for wideband audio applications.
Annex G of H.324 specification defines usage of ISO/IEC 14496-1 (MPEG-4
Systems) generic capabilities in H.324 terminals. H.324/I terminals shall support interoperation with voice telephones using G.711
speech coding, if the connected network supports transmission and reception of G.711. Other modes such as G.722
audio may optionally be supported as well.
H.324 was adapted by 3GPP
to form 3G-324M
.
It is for example used in the Vialta Beamer BM-80 Phone Video Station, the MINX system from Datapoint Corporation, and in several other videophones.
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
recommendation for voice
Voice message
Voice message refers to a message that could be sent to a destination using voice media. Voice itself could be 'packaged' and sent through the IP backbone so that it reaches its marked 'address'. In a technical sense, the process of sending 'voice packets' is a semi passive way of communication...
, video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
and data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
transmission over regular analog phone
Phone
Within phonetics, a phone is:* a speech sound or gesture considered a physical event without regard to its place in the phonology of a language* a speech segment that possesses distinct physical or perceptual properties...
lines. It uses a regular 33,600 bit/s modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
for transmission, the H.263
H.263
H.263 is a video compression standard originally designed as a low-bitrate compressed format for videoconferencing. It was developed by the ITU-T Video Coding Experts Group in a project ending in 1995/1996 as one member of the H.26x family of video coding standards in the domain of the ITU-T.H.263...
codec for video encoding
Code
A code is a rule for converting a piece of information into another form or representation , not necessarily of the same type....
and G.723.1
G.723.1
G.723.1 is an audio codec for voice that compresses voice audio in 30 ms frames. An algorithmic look-ahead of 7.5 ms duration means that total algorithmic delay is 37.5 ms...
for audio.
H.324 standard is formally known as Terminal for low bit-rate multimedia communication. H.324 covers the technical requirements for very low bit-rate multimedia telephone terminals operating over the General Switched Telephone Network (GSTN). H.324 terminals provide real-time video, audio, or data, or any combination, between two multimedia telephone terminals over a GSTN voice band network connection.
H.324 terminals offering audio communication shall support the G.723.1 audio codec. H.324 terminals offering video communication shall support the H.263 and H.261
H.261
H.261 is a ITU-T video coding standard, ratified in November 1988. It is the first member of the H.26x family of video coding standards in the domain of the ITU-T Video Coding Experts Group , and was the first video codec that was useful in practical terms.H.261 was originally designed for...
video codecs.
G.722.1
G.722.1
G.722.1 is a licensed royalty-free ITU-T standard audio codec providing high quality, moderate bit rate wideband G.722.1 is a licensed royalty-free ITU-T standard audio codec providing high quality, moderate bit rate (24 and 32 kbit/s) wideband G.722.1 is a licensed royalty-free ITU-T standard...
may be used for wideband audio applications.
Annex G of H.324 specification defines usage of ISO/IEC 14496-1 (MPEG-4
MPEG-4
MPEG-4 is a method of defining compression of audio and visual digital data. It was introduced in late 1998 and designated a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group under the formal standard ISO/IEC...
Systems) generic capabilities in H.324 terminals. H.324/I terminals shall support interoperation with voice telephones using G.711
G.711
G.711 is an ITU-T standard for audio companding. It is primarily used in telephony. The standard was released for usage in 1972. Its formal name is Pulse code modulation of voice frequencies. It is required standard in many technologies, for example in H.320 and H.323 specifications. It can also...
speech coding, if the connected network supports transmission and reception of G.711. Other modes such as G.722
G.722
G.722 is a ITU-T standard 7 kHz wideband speech codec operating at 48, 56 and 64 kbit/s. It was approved by ITU-T in November 1988. Technology of the codec is based on sub-band ADPCM ....
audio may optionally be supported as well.
H.324 was adapted by 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...
to form 3G-324M
3G-324M
3G-324M is the 3GPP umbrella protocol for video telephony in 3G mobile networks.The 3G-324M protocol operates over an established circuit switched connection between two...
.
It is for example used in the Vialta Beamer BM-80 Phone Video Station, the MINX system from Datapoint Corporation, and in several other videophones.