Low Power Compression for Mobile Video Recording Using a Combination of H'264 and WynerZiv Coding - PowerPoint PPT Presentation

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Low Power Compression for Mobile Video Recording Using a Combination of H'264 and WynerZiv Coding

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Title: Low Power Compression for Mobile Video Recording Using a Combination of H'264 and WynerZiv Coding


1
Low Power Compression for Mobile Video Recording
Using a Combination of H.264 and Wyner-Ziv Coding
2
Outline
  • Introduction- MORE DESCRITPITON
  • Combination of H264 and Wyner-Ziv
  • Simulation Result
  • Future Work

3
Application Scenario
4
Introduction
  • Conventional Codec
  • High complexity encoding
  • Low complexity decoding
  • Wyner-Ziv Codec
  • Low complexity encoding
  • High complexity decoding
  • Combined Scheme
  • Base Layer
  • Coding low resolution conventionally
  • Enhancement Layer
  • Coding high resolution in Wyner-Ziv scheme

5
Goal
  • Lower overall complexity than conventional codec
  • Power saving in encoding
  • Real-Time demonstration
  • Realized in TriMedia Platform
  • Show the importance of temporal interpolation
  • Benefit from the Natural Motion in TV technique

6
Outline
  • Introduction
  • Combination of H264 and Wyner-Ziv
  • Simulation Results
  • Future Works

7
Coding Scheme
Bernd Girod, Low-Power Compression for Mobile
Video Recording Using a Combination of H.264 and
Wyner-Ziv Coding, June 2005
8
More des.
  • Rate control of WZ with BL Modes MVs
  • Bit allocation between BL and EL
  • Side information
  • Gain of using interpolation error
  • Rate distortion Performance
  • Complexity

9
change title
  • Set up simulation environment
  • Design interfaces
  • Integrate H.264 as a library
  • Investigation channel decoding implementation
  • We chose 6-bit quantization PLR (authors year)
  • Avoid floating point
  • Negligible rate loss
  • Represent in byte
  • Optimization on TriMedia platform
  • Rate-distortion improvement
  • Adopting Philips Natural Motion MCI
  • Using Decoded Enhancement Layer

10
Current Status
11
Current Status
  • Up/Down Sample ZOH, 6-tap FIR
  • H.264 codec TML 90 (Ported as a Library)
  • Interpolator
  • Temporal Philips Natural Motion
  • Spatial ZOH, 6-tap FIR
  • Wyner-Ziv
  • H264 Intra quantization, 4x4 Transform
  • LDPC channel coding

12
Wyner-Ziv Codec for Video Signal
13
Use of Enhancement Layer
14
Use of Enhancement Layer
Prediction only from base layer
Prediction with Enhancement Layer
15
LDPC Decoding Consideration
  • For Trimedia Platform
  • 5 issue slots
  • 2 load/store units
  • 16k Cache
  • SIMD instructions
  • Prefer
  • Fix points operation
  • lt8 bits for message
  • Use 6-bit quantization table lookup (4kbytes)
    2
  • Or
  • 1 load/store units
  • 128K Cache

16
Required Throughput
17
Throughputs of different Implementations
Src Architecture and Implementations of
Low-Density Parity Check Decoding Algorithms,
Midwest Symposium on Circuit and System, 2002 3
93kbps
46Mbps
1.1Mbps
18
Video Codec Speed
  • Coding 15 frames of Foreman CIF
  • B24, E12 (5 bit planes)
  • LDPC block size 6336 for Luma, 396 for Chroma
  • Without optimization on PC

Note H264 coding QCIF
19
Outline
  • Introduction
  • Combination of H264 and Wyner-Ziv
  • Simulation Results
  • Future Works

20
Simulation Results
  • Rate-Distortion Performance
  • Different Prediction Modes
  • (Symbols too small)

21
Compare with/ without FIR
foreman CIF 31 frms PSNR of Luma Rate
Entropy Quant Set 4,12, 18, 24, 28
22
Setup
  • Video Source CIF, 31 frames
  • Distortion PSNR of Luminance
  • Rate Entropy
  • Up-sample FIR
  • Temporal Interpolation SNM
  • Quantization Parameter
  • E,B 4,12,18,24,28

23
Prediction Modes
24
Notation
  • P picture
  • the picture has corresponding lower resolution
    picture
  • B picture
  • the picture has no corresponding lower resolution
    picture
  • Pred_XY
  • X the prediction mode of P picture
  • Y the prediction mode of B picture
  • 0 from base layer, 1 from enhancement layer
  • Pred_mv
  • Using Pred_11, but no residue coded at base
    layer, independent from base layer except using
    mv and modes.
  • Pred_1p
  • P means perfect for B picture

25
Side Information
(a) Up sampled base layer
Motion Compensated (b)
(c) MCI of EL
MCI of BL (d)
26
Coded Rate vs. Frame
27
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28
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29
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30
Summary
  • 3 dB gain with FIR spatial filter
  • 1 dB gain from NM-MCI of enhancement layer
  • 0.5 dB gain from MC at low bit rate base layer
  • 0.5 2 db by removing base layer redundancy
  • 4 dB Rate-Distortion gap from H264
  • 1dB gap from H264 in ideal case at high bit rate

31
Outline
  • Introduction
  • Combination of H264 and Wyner-Ziv
  • Simulation Results
  • Future Work

32
Future Work
  • Rate Distortion Optimization
  • Discover the correlation between BL mode, mv, and
    rate
  • Base Layer H264 CBP, skip modes
  • Adaptive spatial up-sample filter
  • Rate Control (Estimation) at Encoder

33
Rate Distortion Optimization
  • Using predicted signal (from side info b1bn-1)
  • Choose not to code if -?R/?D gt ?

34
Rate Distortion Optimization
35
Adaptive Up-Sample Filter
  • Learn the partitions from previous pairs
  • Adapt the coefficients of up-sample filter
  • Discover the correlation between base and
    enhancement layer at decoder
  • Make use of enhancement layer at spatial direction

36
Conclusion Discussion
  • Set up Initial Simulation Environment
  • Optimize Rate-Distortion Performance
  • Benefit from Natural Motion
  • Lower the complexity
  • Benefit from TriMedia Platform

37
Acknowledgement
  • Thanks Prof. Girod for this great idea
  • Thanks Erwin, Torsten, Mark, Maurice, and Ralf
    for helpful discussions and suggestions.

38
Reference
  • 1 Bernd Girod, Research Proposal Low Power
    Compression for Mobile Video Recording Using a
    Combination of H.264 and Wyner-Ziv Coding, June
    2005
  • 2 L. Ping and W.K. Leung, Decoding Low Density
    Parity Check Codes with Finit Quantization Bits,
    IEEE Communication Letters, Vol. 4 No. 2, Feb
    2000
  • 3 E. Yeo, B. Nikolic, and V. Anatharam,
    Architectures and Implementations of Low-Density
    Parity Check Decoding Algorithm, Midwest
    Symposium on Circuit and System, 2002
  • 4 W. E. Ryan, "An Introduction to LDPC Codes,"
    in CRC Handbook for Coding and Signal Processing
    for Recording Systems (B. Vasic, ed.) CRC Press,
    2004

39
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