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Institut für Informationsverarbeitung Two-dimensional Non-separable Adaptive Wiener Interpolation Filter for H.264/AVC Yuri Vatis Institut für Informationsverarbeitung,

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Presentation on theme: "Institut für Informationsverarbeitung Two-dimensional Non-separable Adaptive Wiener Interpolation Filter for H.264/AVC Yuri Vatis Institut für Informationsverarbeitung,"— Presentation transcript:

1 Institut für Informationsverarbeitung Two-dimensional Non-separable Adaptive Wiener Interpolation Filter for H.264/AVC Yuri Vatis Institut für Informationsverarbeitung, Universität Hannover ITG-FA 3.2, 23.06.2005

2 Institut für Informationsverarbeitung 2 Outline Introduction Motion Compensated Prediction Adaptive Interpolation Filter Experimental Results Conclusion

3 Institut für Informationsverarbeitung 3 Introduction Hybrid Video Encoder: + - + + MCPz -1 T -1 Quant T ME EC Video inputBitstream s(t) s(t-1) d(t) e(t)

4 Institut für Informationsverarbeitung 4 Motion Compensated Prediction (MCP) s(t-1) block to code s(t) reference block d(t)

5 Institut für Informationsverarbeitung 5 Motion Compensated Prediction (MCP) image signal on sub-pel positions has to be generated by interpolation s(t-1) block to code s(t) reference block j i Prediction is distorted by: 1. Aliasing in s(t) and s(t-1) 2. Displacement estimation errors of d(t) 3. Quantisation errors in s(t-1) 4. etc. The distortions depend on the motion and content of the video signal MCP with fractional-pel Motion Vector Resolution d(t)

6 Institut für Informationsverarbeitung 6 2D non-separable Adaptive Interpolation Filter Analytical design of a non-separable adaptive 2D interpolation filter. Goal: –Prediction (and not just interpolation) of picture elements by minimising prediction error energy. –Reduction of aliasing and blurring effects, motion estimation errors. Properties: –Symmetric, non-separable 6x6-tap filter. –Filter coefficients are calculated analytically once per frame with respect to all reference frames.

7 Institut für Informationsverarbeitung 7 Adaptive Interpolation Filter Value ( ) to be interpolated: where is an integer sample value ( ) and are filter coefficients for sub-pel position SP

8 Institut für Informationsverarbeitung 8 Analytical Calculation of Filter Coefficients The calculation of coefficients and the motion compensation are performed in the following 3 steps: 1)Displacement vectors are estimated for every image to be coded (standard interpolation filter is used). 2)Independent calculation of 2D filter coefficients for each sub-pel position by minimisation of the prediction error energy: with

9 Institut für Informationsverarbeitung 9 Analytical Calculation of Filter Coefficients 3)Estimation of new displacement vectors (applying the adaptive interpolation filter computed in 2). Reducing motion estimation errors, caused by aliasing, camera noise etc. Treating the problem in the rate-distortion sense. The software was declared as a VCEG KTA- Software

10 Institut für Informationsverarbeitung 10 Quantisation and Coding of Filter Coefficients Quantisation with 8 bits (magnitude). Required side information for filter coefficients @30 fps ( [VCIP05] ): PCMVCIP05 14.6 kbit/s3-10 kbit/s

11 Institut für Informationsverarbeitung 11 Results CIF ( HDTV) ProfileIDC100 QPISlice23, 27, 31, 35 IntraPeriod0 QPPSlice24, 28, 32, 36 NumberBFrames3 QPBSlice25, 29, 33, 37 BReferencePictures1 PyramidCoding1 PyramidLevelQPEnable1 SearchRange32 (64) NumberReferenceFrames5 (3) SymbolMode1 AdaptiveRounding1 Transform8x81

12 Institut für Informationsverarbeitung 12 Concrete, CIF, 400 Frames @ 30 fps

13 Institut für Informationsverarbeitung 13 Crew, HDTV(720p), 20 Frames @ 60 fps

14 Institut für Informationsverarbeitung 14 Raven, HDTV(720p), 40 Frames @ 60 fps

15 Institut für Informationsverarbeitung 15 Sunflower, HDTV(1080p), 100 Frames @ 25 fps

16 Institut für Informationsverarbeitung 16 Conclusions Average of 12% bit rate savings compared to the standard H.264/AVC Slightly increased decoder complexity Number of operations needed for interpolation is increased Suitable for 24-bit arithmetic


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