SystemonChip SoC Implementation of Multimedia Systems

1
System-on-Chip (SoC) Implementation of
Multimedia Systems

• Yu Hen Hu
• Univ. of Wisconsin Madison
• Dept. ECE
• Madison, WI 53706
• hu_at_engr.wisc.edu

Shen-Fu Hsiao National Sun Yat-Sen Univ. Dept.
CSE Kaohsiung, Taiwan sfhsiao_at_cse.nsysu.edu.tw
2
Observations

• Embedded, low power multimedia communication
  systems are emerging applications that demand a
  SoC platform based solution.
• The high-level of integration and complexity of
  SoC require close match between the algorithm and
  the architecture.
• Two issues will be addressed
• Communication
• Interface
• One should design MM/Comm algorithms such that it
  requires local communication and have flexible
  interface requirements.

3
The SoC Edge
Technology Demand and Supply

• Initially, the development of sustaining
  technology such as general purpose ?P focused on
  performance (thick line) improvement to meet
  demand (dashed line)
• After the performance surpassed the demand,
  disruptive technology such as SoC come in late in
  the game, focusing on
• Time-to-market
• Customization
• Price/performance ratio
• Power consumption

Computing power
Disruptive technology
performance
workstation
PC
embedded

• Time-to-market
• Customization
• Price
• Power consumption

Sustaining technology
time
M.J. Bass Clayton Christensen, the future of
the microprocessor business, IEEE Spectrum, April
2002, pp. 34-39.
4
Widening Hw/Sw Gap

• Hardware
• Performance improves according to Moores law
  (exponentially).
• Cost is lower and lower
• Manufacture
• Service
• Design cost increase!
• Verification
• Simulation
• ? New generation of CAD software is in desperate
  needs for SoC design.

• Software
• Relatively stable
• Unix 30 years!
• Mac OS 20 years!
• MS Window 20 years!
• High cost in developing software
• MS Office cost more than a low end PC!
• CAD software always lags behind hardware
  development!
• ? SoC application must address software
  compatibility issue.

5
SoC Platforms

• Platform
• A platform consists of compatible hardware Ips
  (processor, buses), software Ips (OS,
  application), design tools (CAD software,
  prototype system, etc) and technical support
  services to facilitate the development of SoC
  systems.
• Platform based design is to meet the software
  compatibility requirements

• SoC Platforms
• Processor centric
• use proven processor core, such as ARM
• Software compatible
• Communication centric
• use uniformed bus architecture
• Standardized communication interface
• Re-configurable
• use FPGA plus processor core
• More flexibility in ASIC IP design.

6
A Design Chain of MM SoC

• Electronic design chain is a supply chain
  management model to manage the complexity of SoC
  design.
• Each design chain is based on a particular
  platform including programmable ?P core, OS,
  ASIC module IPs, application softwares, APIs,
• Platform examples Philips Semiconductors
  Nexperia, Texas Instruments Open Multimedia
  Applications Platform (OMAP), ARMs PrimeXsys,
  Infineons MGold Platform, and Intels Xscale
  Architecture.

Embedded SoC provider-integrator design
chain Martin, G., and F. Schirrmeister, IEEE
Computer, March 2002
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Applications That Demand SoC

• Multimedia Applications
• Audio/Video/image codec
• Graphics, rendering, visualization, virtual
  environment
• Content analysis
• Properties of MM Apps
• Data intensive rather than control intensive
• Bit operations
• High-speed, real time operations
• Continuous rather than intermittent operations

• Communication applications
• Software defined radio
• Base station
• Wireless Lan (802.1x)
• Ad hoc network (Bluetooth)
• Properties of Comm. Apps
• Bit operations
• High speed
• Programmability
• Portability
• Low power

8
Multimedia SoC Design Issues

• Communication
• Cost of communication increases as feature size
  shrinking
• Relative delay
• Signal integrity
• Overhead in clock buffer, bus driver, insulation
  all increase
• Localized communication is more desirable than
  global communication (e.g. clock)
• Off-chip communication with external memory
  sub-system costs much higher

• Interface
• Due to proliferation of different platforms,
  there is no unique, prevailing standards to
  define the interaction between different IPs.
• Interface incompatibility requires custom design
  of interface modules
• to convert data format,
• to rearrange data movement patterns,
• sometimes, incompatible IPs can not be used in
  the same design.

9
Communication Issue

• Current communication methods
• Bus
• shared medium
• Time shared access
• Direct connection
• Switches
• Used mostly in FPGA or high performance PDSP (TI
  C80s, e.g.)
• Parallel access
• Direct connection
• Programmable
• Routers
• RAW architecture

• Network-on-chip
• Incorporating layered network strategy (e.g the
  7-layer model of OSI) to manage the complexity of
  communication.
• Similar to
• wide area network
• Parallel processor interconnection network
• SoC distinct characteristics
• On-chip communication,
• Delay sensitive, power, etc.

10
Interface Issues

• IP designer must make assumption on the data
  input output patterns and behaviors.
• Since there is no standard available, interface
  can be very challenging.
• Interface problems
• Incompatible data format
• Incompatible timing
• Incompatible data organization
• Etc.

• Possible solutions
• Standardization
• May limit innovation and performance
• Re-configurable interface
• Based on description of interface requirements of
  interfacing IPs, automated configuration of
  necessary interface.

11
MPEG Encoding
Buffer control
Current frame x(t)
r
Bit stream Buffer

VLC
DCT
Q
?
Q-1
This is a simplified block diagram where the
encoding of intra coded frames is not shown.
IDCT

r(t) reconstructed residue
Xp(t) predicted frame


x(t) reconstructed current frame
Motion Estimation Compensation

x(t)
x(t-1)
Frame Buffer
Motion vectors
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Software Defined Radio
A direct-conversion software-defined radio can
handle a wider range of frequencies and
bandwidths because it goes directly from RF to
base-band (or vice versa) without an I-F section
and its inflexible components.
Bing Jayant, IEEE Spectrum, May 2002.
13
Blue-tooth

• An Ad hoc LAN technology for short distance
  wireless communication between different
  bluetooth-enabled devices, called a pico-net.
• Low power, low cost is the main concern.

14
MP-III Audio Codec
Rate and distortion control lope
Scaler Quantizer
Mux
Hoffman Coding
Analysis Filterbank
MDCT w/ Dynamic Windowing
Digital Channel
Coding of Side Info
FFT
Masking Threshold
PCM input
De- mux
Dequan- tizer Descaler
Synthesis Filterbank
Hoffman Decoding
Inverse MDCT w/ Dynamic Windowing
PCM output
Decoding of Side Info
15
Data Movement Intensive Operations in MM
Applications

• Row-Column transpose memory
• Smaller size in 8x8 2D DCT/IDCT
• Larger size in 2D FFT/IFFT or WT
• Bit-plane coding
• Word-serial to bit-serial and vice versa
• Buffers between MEM and Functional units
• Zigzag Scan ordering
• Bit-reverse operation
• Data type conversion
• Word, half-word, byte, bit

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System Level Considerations in Implementing
MM/Comm SoCs

• Characteristics of Comm/MM applications
• Deterministic and relatively predictable control
  and data flow
• Intensive data input and output
• Data reformatting required
• Bit/word level
• Array level
• Parameters for system design
• Selection of algorithms
• Selection of IPs to implement a specific
  algorithm

• What are needed
• In depth analysis of existing MM/Comm algorithms
  regarding their requirement for data movement and
  communication requirements.
• A representation to describe the communication
  and interface requirements at system (behavioral)
  level
• A set of IPs that implement varying communication
  and interface solutions.