Low-power Wireless Video System
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Transcript Low-power Wireless Video System
Low-Power Wireless
Video System
Advisor: Professor Alex Doboli
Students: Christian Austin
Artur Kasperek
Edward Safo
Objective
Ÿ Streams
MPEG4
video from server
through wireless
communication to
the Laptop/PDA
am
tre
Ÿ Running
Video Server
Ÿ Maintains
database
of MPEG4
files
Access Point
ys
Use MPEG-4 video
standard.
Hardware software codesign for low-power
video decoder
implementation.
Server
r
nta
me
ele
802.11B
11Mbit
4
EG
MP
Establish a low-power
wireless client/server
streaming video
system.
Ÿ Running
MPEG-4
Client
Software
Ÿ Running
MPEG-4 Client
Software
PDA
What is MPEG-4 and Why Use It?
What is MPEG-4?
Object based video compression and decoding
standard.
Builds on previous MPEG and H.263 standards.
Why use MPEG-4?
High compression makes streaming over low
bandwidth network practical (e.g. wireless).
Adjustable resolution coding allows for video
continuity/quality trade off.
High bit-rate yields better quality video at the expense of
lost frames…
MPEG-4 Framework
Multimedia
Content
Monitor
Scene Compositor
Audio
Objects
MPEG-4
Client
Framework
Scene
Description
Information
Video
Objects
Audio
decoder
Audio
Streams
Video
Decoder
Scene
Description
Streams
Video
Streams
Sync Layer
Protocol
Independent
Streams
DMIF Layer
Local
Streams
MPEG-4
Data
Streams
Network
Streams
Hardware/Software Co-Design
Design methodology that splits a
computer system’s design between
hardware and software in an effort to
improve some feature of the system.
Partitioning targets low power consumption
in this design.
Achieved by relocating the functionality of
high power sections of code to specialized
hardware.
Power Intensive Software
Locating code.
Hardware power profiling.
Software profiling (e.g. GPROF,
VS).
Power estimation software (e.g.
SimplePower).
Inverse Discrete Cosine Transform
(IDCT).
Computational intensive.
High frequency of memory
accesses.
IDCT
Hardware Implementation
Determine functional units needed to
implement the IDCT.
Multipliers and adders.
Map functional units into hardware to
realize the IDCT.
VHDL description of functional units,
Xilinx FPGA based PCI board.
Hardware Power measurements.
Optimize Hardware for low power.
Add power control logic.
Restructure combinational logic to reduce
glitching.
Increase pipelining.
Goals and Applications
Demonstrate that a low-power wireless video
system is practical.
Design for a power constrained, low bandwidth
PDA.
Applications:
Interactive shopping.
Request video of product information while shopping.
Multimedia preview.
Preview movie before buying or renting; watch music
video while previewing new album.