Glossary

T.120 is an ITU-T standard that was designed to create a self-sufficient set of data collaboration tools, which may be used either as standalone or in the content of a multipoint videoconference. T.120 protocol stack architecture While T.120 provides rather advanced features, it also comes with great complexity and found ...

"Talking heads" is a term usually used to define a point-to-point video calling scenario, where the video displayed shows both people on from the shoulders and up. At its core, it is the most basic layout for video telephony, often considered as not compelling enough for more advanced video calling ...

Temporal scalability is scalability in terms of frame rate, meaning that a given bit stream includes different sub-streams each with a different frame rate. For instance, an H.264 SVC bitstream with temporal scalability can have 3 layers: base layer of 15 frames per second, 1st enhancement layer of 30 frames ...

TLV (Type Length Value) encoding is a general technique of encoding messages to a network representation. In TLV, each field is designated a type, which gets encoded. Then the lengh of the value is added and after that the value of the field itself. TLV is used in Q.931 encoding.

Transcoding is the conversion of one transmission format into another using various algorithms to achieve wider support of formats at different quality levels.In the context of video communications, transcoding will usually take place between video codec formats and voice codec formats.The operation of transcoding brings with it several challenges:Transcoding increaes ...

Transrating means changing the bitrate (bandwidth) of a stream by means of processing. For instance, processing an input video stream of 1Mbps so that the output stream is 256Kbps only. Transrating can increase or decrease the bitrate, and usually involves changing the encoding parameters (usually quantization).See also: Transcoding