Advanced in recent years in memory management areas
include robust algorithms for reducing size of image, video, or audio data
and vlsi architectures for relatively low-cost but sophisticated compression
processes, thus spurring developments of codecs. [ref: Multimedia
Telecommunication News] A codec is a system that will encode
and decode multimedia information; generally as compressor and decompressor.
This implies that we may be able to treat multimedia information
as just another data type that can be manipulated, transformed, stored,
and transmitted as complete information; not as individual types cobbled
together. This presents the possibility of standardization across
different platforms and applications. Different standards for compression
methodologies will be presented from algorithmic and architectural viewpoints
for image and video data will be presented.
II. Background
The basic task of a codec is to compact a given signal
for efficient representation. Table 1 presents a list for applications
that can benefit for a standardized codec.
Application |
Data
Uncompressed |
Rate
Compressed |
Voice
8k samples/s, 8 bits/sample |
|
|
Slow-motion video (10 fps)
framesize 176x120, 8 bits/pixel |
|
|
Audio conference
8k samples/s, 8 bits/sample |
|
|
Video conference (15 fps)
framesize 352x240, 8 bits/pixel |
|
|
Digital audio (stereo)
44.1k samples/s, 16bits/sample |
|
0.128-1.5 Mbps |
Video file transfer (15 fps)
framesize 352x240, 8 bits/pixel |
|
|
Digital video on CD-ROM (30 fps)
framesize 352x240, 8 bits/pixel |
|
|
Broadcast video (30 fps)
framesize 720x480, 8 bits/pixel |
|
|
HDTV (59.94 fps)
framesize 1280 x 720, 8 bits/pixel |
|
|