Video Coding
for the TMS320C5x
by Signals and Software Limited

Software Overview

A proprietary implementation of a very-low data-rate video-coding system. The decoder complies with 
the ITU H.261 structure. Two types of coding may be used: QCIF, which codes at 10 frames per second 
(fps), and subQCIF, which codes at 15 fps.

Features and Benefits

Format QCIF (144¥176 Pixels)
Luminance	Y - 144¥176
Chrominance	U - 72¥88
		V - 72¥88
Sub-QCIF (128¥96)
Luminance	Y - 128¥96
Chrominance	U - 64¥48
		V - 64¥48
Main components of the coder include:
•	Motion compensation
•	Transform (DCT)
•	Quantizer
•	2D VLC coding
•	Entropy coding

Main classes of operation:
•	Intra frame
•	Inter frame
–	Motion compensated (filtered or non-filtered)
–	Non-motion compensated
•	Coded
•	Non-coded

Processor and System Requirements

Video Coder
Program Memory
(Words)
Data Memory
(Words)
Processing Load (MIPS)
Code
Data Tables
Internal
Frame
Sub-QCIF
Encoder + decoder
9971
441
1219
24576
~62
Decoder only
3250
202
754
QCIF
Encoder + decoder
9971
565
1086
46464
~83
Decoder only
3250
231
465

Usage Limitations or Performance Considerations

Applications include 
•	Low-cost PSTN videophones as stand-alone units or PC cards
•	Remote monitoring
•	Home shopping
•	Security

Availability

An Application Note is available. Support consultancy for code integration is also available.

Company Background and Contact Information

Signals and Software Limited (SASL), based in Harrow, Middlesex, UK is a design consultancy 
specializing in the area of Digital Signal Processing (DSP). From concept and algorithm design 
through to real-time DSP implementation, SASL is able to offer its clients fast and cost-effective 
solutions to their DSP needs. Services include: feasibility studies, DSP software to order, DSP 
research and algorithm design, computer simulations (C or PASCAL), and hardware design. In support 
of these services, SASL offers a range of "off-the-shelf" software that includes audio/speech 
coding, modems, acoustic echo cancellation, video coding, and general telecommunications functions. 
Key technology areas include: GSM/PCN Mobile Comms, VideoConferencing, VideoTelephony, and 
PSTN/ISDN Voice and Data Transmission.
Contact:	David Morley
		3 Jardine House
		Bessborough Road
		Harrovian Business Village
		Harrow, Middlesex, HA1 3EX
		United Kingdom
		+44 (0) 181 426 9533
		Fax: +44 (0) 181 869 1182
		e-mail: davem@sasl.demon.co.uk