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Encoding stored video for stremming applications ieee paper ppt

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Concepts of Computer Network, Digital Communication, Optimization Techniques are used.

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Encoding stored video for stremming applications ieee paper ppt

  1. 1. Outline  Introduction  Background Study  Problem Statement  Contribution of Paper  Sliding-Window Encoding Scheme  DCT Coefficient Selection  Simulation Result  Conclusion  References
  2. 2. Introduction Digital video applications have become increasingly popular. There are several video standards established for different purposes.  e.g, MPEG-1, MPEG-2, H.263… Delay is an important issue in real-time communication.
  3. 3. Background Study Streaming video applications  Video sequences are  Encoded off-line  Stored in a server  Pre-load before playback  E.g, VOD
  4. 4. Problem Statement  Bit allocation and video quality  Minimum distortion under the rate constraint
  5. 5. Sliding-Window Encoding Scheme Use future frames to improve video quality. Set window size W to encode video frame.  frames : i, i+1, …, i+W-1  let frame i be the current frame This proposed encoder better than real-time’s for the same bitrate.
  6. 6. Buffer-size and Pre-loading Time Requirement  Why need buffer?  Store the excess bit waiting to be decoded e.g, bits of future frames  Why need pre-loading time?  The delay before playback
  7. 7. DCT Coefficient Selection  Quantize the DCT coefficients  rate-distortion sense and macroblock level.  quantizer step-sizes(Q) largely determine the rate-distortion tradeoff.  There are not optimal for all video sequences by  limited quantizer selections and  predetermined run-length codeword.  The encoder can adjust the quantized coefficient’s level.  a marginal distortion increase but  a significant bit-rate reduction.
  8. 8. Simulation Result Different bitrates:  32, 64, and 128 kbits/s Different types of video sequences:  large facial movement  head and shoulder  camera panning Compare with TMN8
  9. 9. CONCLUSION Better video quality than TMN8 in high motion-activity frames and scene-change frames. Require more buffer size and pre-loading time than TMN8.
  10. 10. References[1] Coding of moving pictures and associated audio for digital storage media at up to about 1.5Mbit/s, ISO/IEC 11 172, Aug. 1993.[2] Generic coding of moving pictures and associated audio information, ISO/IEC 13 818, 1995.[3] Video coding for low bit rate communication, ITU-T Recommendation H.263, March 1996.[4] G. Cote, B. Erol, M. Gallant, and F. Kossentini, “H.263+: Video coding at low bit rates,” IEEE Trans.Circuits Syst. Video Technol., vol. 8, pp. 849–866, Nov. 1998.[5] Test model 5, JTC1/SC29/WG11 coding of moving pictures and associated audio MPEG96/1260, ISO-IEC/JTC1/SC29/WG11, Mar. 1996.[6] Video codec test model, TMN8, ITU-T/SG15, Jun. 1997.[7] Encoding Stored Video For Stremming Applications, IEEE Transactions On Circuits And Systems ForVideo Technology, Vol. 11, No. 2, February 2001

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