1. A New Coding Mode for Error Resilient Video EE368C Final Presentation Stanford University Sangoh Jeong Mar.8, 2001

2. Outline  Use of Leaky Prediction + RD theory for Improved Error Resiliency  General Hybrid Video Codec  Proposed New Coding Mode  RD-Based Mode Selection  Experimental Environment  Results

3. Data Units  GOB(Group Of Block)s, MB(Macroblock)s and Blocks - Example : For QCIF(9GOBs), 176 (11MBs) 144 (9GOBs) QCIF picture 0 1 7 8 16 8 8 MBs Y Cr Cb GOB # 1 2 3 4 56 Block

4. General Hybrid Video Codec DCT IQ MC + Q IDCT ME Frame Memory Current MB Search Area MV Input Video Intra Inter MCed MB Pe Compressed Bitsteam Encoder IQ MC IDCT Frame Memory MV Inter Decoded Video Compressed Bitsteam Intra Decoder

5. The Leaky-Inter Mode  Prediction Error  Leaky Prediction Attenuates the energy of the prediction signal Superimposed errors decay over time Encoding of : Intra, Inter Reconstructed FrameOriginal Frame MB1MB2

6. RD-Based Mode Decision  Cost Function & Decision Process Intra Mode : Inter Mode : Leaky-Inter Mode : Value of : Find the Reconstructed Frame Compute the Distortion Compute the Rate Involved Compute the Cost Choose the Mode with the Minimum Cost

7. Encoder Setup DCT IQ MC + Q IDCT ME Frame Memory 1 Current MB Search Area MV Input Video Intra Inter RD-Based Coding Control MCed MB1 Pe IQ IDCT Frame Memory 2 GOBs loss and concealment Feedback No Feedback MCed MB2

8. Encoder and Experiment  Encoder Software Used H.263 Encoder V2.0 (TMN-8) RD-Based Mode Decision Realized for Experiment  Error Resiliency Experiment Effect of Leaky-Inter Mode - Case1 : Operation Without Errors, regarding values - Case2 : Operation With Errors, regarding values Effect of Leaky-Inter Mode with Assumed Feedback - 3-Mode Operation with Errors, regarding an

9. Conditions on Experiment  The Pattern of Errors GOB Loss rate : 6.67% : Random Burst Loss of 3 GOBs / 5(average) decoded frames. Same positions of errors applied to all experiments For Comparison  Assumption Encoder knows the state of the decoder accurately  Error Concealment GOB Concealment from Previous Frame for Errors

10. L-Inter & Intra Result

11. L-Inter & Intra Result (Error case)

12. Resiliency in case of Feedback Resiliency in case of Feedback

13. Conclusion & Future Work  Improved resiliency  Less coding efficiency  Not so helpful with accurate feedback  Further Experiment Encoder knows only the region of errors of the decoded video as feedback information Encode the region of errors with the Leaky-Inter Mode  Future work Find the leaky-coefficient( ) methodically Experiment with realistic transmission channels