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Layered Coding

Layered Coding. Basic Overview. Outline. Pyramidal Coding Scalability in the Standard Codecs Layered Coding with Wavelets Conclusion. Laplacian w/ Gaussian Pyramids. Laplacian w/ DCT Coefficient Pyramids. DCT Pyramid Example. Figure 7.5. Reconstruction Data for Fig. 7.5.

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Layered Coding

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  1. Layered Coding Basic Overview

  2. Outline • Pyramidal Coding • Scalability in the Standard Codecs • Layered Coding with Wavelets • Conclusion

  3. Laplacian w/ Gaussian Pyramids

  4. Laplacian w/ DCT Coefficient Pyramids

  5. DCT Pyramid Example • Figure 7.5

  6. Reconstruction Data for Fig. 7.5

  7. Scalability in the Standard Codecs • Data Partitioning • Signal-to-Noise Ratio (SNR) • Spatial • Temporal

  8. Data Partitioning

  9. SNR Scalable Coder

  10. SNR Scalability – no drift

  11. Spatial Scalability

  12. Temporal Scalability

  13. Scalability Applications • Data Partitioning • Video of ATM networks • SNR • Transmission of video at different qualities • Video on demand, simultaneous TV and enhanced TV • Video over high packet loss networks (Internet) • Spatial Scalability • Internetworking between two different standards • Simulcasting of drift-free video (TV & HDTV)

  14. Scalability Applications • Spatial Scalability (continued) • Reception of low spatial resolution pictures over mobile networks • Temporal Scalability • Migration to HDTV from current interlaced • Internetworking between mobile and fixed networks

  15. Layered Coding with Wavelets • Growing interest due to new efficient coding techniques (Embedded Zero-tree Wavelets, or EZW) • Accepted for coding of still images • MPEG-4 and JPEG 2000 • Predicted to continues in growth

  16. Discrete Wavelet Transform • Split signal spectrum into several frequency bands analysis filters Figs. 7.27, 7.28, 7.29

  17. Distortions

  18. Filter Bank Solutions

  19. Higher Order Systems Multiple wavelet transform coding by means of repeated two-band splits

  20. Further Considerations • Wavelet Example – Fig. 7.32 • Zero-Tree Coding – Fig. 7.34 • Quad-Tree Representation • Bands look like scaled versions of each other • Lower bands have 0.25 dimension of higher

  21. Conclusion • Layered coding facilitates • Error protection • Efficient use of resources • Multiple services • Customer satisfaction

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