Image Processing Reference
A single picture within a video sequence.
An audio codec supporting 3.4-KHz speech at 56 and 64 Kbps.
An audio codec supporting 7-KHz speech at 48, 56, and 64
An audio codec supporting 3.4-KHz speech at 16 Kbps.
Generator locking describes the technique of synchronizing the
film shutter in a camera with an external electronic source. This
generator locking is also used to sync any two arbitrary video
systems together. Studio and production environments typically
provide genlock signals via a distribution amplifier so that all
the equipment can be synchronized to the same timing.
A spatial transform applied to the whole picture in order to
reduce the residual motion vectors required in each macroblock.
A standard that describes the transmission frame structure. This
is based on frame multiplexing for a 64- to 1920-Kbps ISDN
Describes a Multipoint Control Unit (MCU) for video-
conferencing systems with more than 2 end-points.
A system for establishing communication between three or more
terminals with circuits that have a capacity of up to 2 Mbps.
This is sometimes called multi-point conferencing.
An ITU standard codec for video-conferencing video streams.
H.261 uses the Discrete Cosine Transform (DCT) algorithm to
compress video so it can be accommodated within a bandwidth
of 64 Kbps to 2 Mbps. This standard also defines the CIF and
QCIF image formats. This is a legacy codec.
Another ITU video-conferencing standard codec; offers better
compression than H.261. This is particularly well suited to
compression down to the low bit rate available through dial-up
modems. Probably not an optimal choice these days. Used to be
a good codec for use on low-powered playback hardware.
The newest and most advanced codec. This is the one codec to
rule them all. It is a modern codec developed for consumer
applications at much better bit rate/performance trade-offs than
MPEG-2. Although not technically a video-conferencing
standard, some telecommunications companies are looking at
deploying this for delivery of video content to mobile phones.
Early trials of the H.264 standard were tested under the H.26L