Image Processing Reference
The modem equipment at each end of a telephone line is used to
create a data connection between two systems. The word is
contracted from modulator-demodulator.
Modulator-demodulators are used to transfer digital signals
over analog telephone lines.
The use of motion vectors to improve the compression of
macroblocks by recycling previously decoded blocks and
applying a move to them before adding residual data.
The process of generating motion-compensating vectors during
the encoding process. Technically, this is the most difficult part
of the algorithm to understand.
A means of creating moving-image files by storing a series of
still images that are individually coded with the JPEG standard
protocol. This is a key frame-only format but now that the JPEG
standard has been revised to the wavelet-based JPEG 2000
version, this is a somewhat dated codec. Motion JPEG is still
widely used since it is embedded in a lot of studio-quality video
servers but it is a legacy format when choosing codecs for new
This is used to compensate for motion when constructing one
macroblock from another. These vectors can be forward- or
backward-referencing and are specified in two dimensions.
MPEG-1 Audio Layer 3.
Motion Picture Experts Group. A working group within the
ISO/IEC standards body. This group is concerned with the
standardization of moving-picture representations in the digital
The original MPEG video standard designed for CD-ROM
applications and other similar levels of compression. This is a
legacy format. Still useful for some solutions but new projects
should use a later codec.
Widely used for digital TV and DVD products. A much-
improved codec that supersedes MPEG-1 in many respects. It
has been popularized by DVD content encoding and DVB
This was cancelled because the proposed work was included in
MPEG-2 with a small enhancement.
A huge leap forward in the description of multimedia content.
MPEG-4 is the essence container.