Study and Performance Comparison of H 264 AVC Dirac and AVS China Part 7 Project EE5359 Fall 2010 Khan Touseef 1000676051 General Video Coding and Decoding Process 1 An optional preprocessing step the sender might choose to preprocess the video using format conversion or enhancement techniques The encoder encodes the video and represents the video as a bit stream The decoder decodes the video which gets displayed after an optional post processing step which might include format conversion filtering to suppress coding artifacts error concealment or video enhancement H 264 AVC 1 H 264 MPEG 4 AVC is a block oriented motion compensationbased codec standard developed by the ITU T Video Coding Experts Group VCEG together with the ISO IEC Moving Picture Experts Group MPEG It was the product of a partnership effort known as the Joint Video Team JVT H 264 AVC provides gains in compression efficiency of up to 50 over a wide range of bit rates and video resolutions compared to previous standards Supports various applications such as video broadcasting video streaming and video conferencing over fixed and wireless networks and over different transport protocols and results better than MPEG 2 Dirac 24 Hybrid motion compensated video codec developed by BBC Research BBC Uses modern techniques discrete wavelet transforms arithmetic coding Dirac is a general purpose video compression family suitable for everything from internet streaming to HDTV and electronic cinema It offers good quality at low bit rates leading to lower costs It offers good quality with low delay ideal for live broadcast applications in studios and outside broadcasts AVS China Part 7 AVS Mobile 13 Audio video coding standard AVS is a working group of audio and video coding standard in China which was established in 2002 AVS is a set of integrity standard system system video audio and media copyright management AVS China has a coding efficiency similar to that of H 264 except that it has a lower computational complexity AVS M is the 7th part of the video coding standard developed by the AVS Workgroup of China which aims for mobile systems and devices In AVS M a Jiben Profile out of the 10 different profiles of AVS AVS follows a layered structure for the data and this representation is seen in the coded bit stream H 264 Layers 1 The video coding layer VCL defines the efficient representation of the video The network adaptation layer NAL converts the VCL representation into a format suitable for specific transport layers or storage media H 264 Encoder 3 H 264 Decoder 3 Dirac Encoder and Decoder 13 AVS M Encoder 18 AVS M Decoder 18 H 264 AVC introduces the following changes 1 In order to reduce the block artifacts an adaptive deblocking filter is used in the prediction loop The deblocked macroblock is stored in the memory and can be used to predict future macroblocks The memory contains one video frame in previous standards H 264 AVC allows storing multiple video frames in the memory In H 264 AVC a prediction scheme is used also in Intra mode that uses the image signal of already transmitted macroblocks of the same image in order to predict the block to code The discrete cosine transform DCT used in former standards is replaced by an integer transform H 264 Profiles 1 A profile is defined as a subset of the entire bit stream syntax or in other terms as a subset of the coding tools There are three profiles in the first version Baseline Main and Extended There are four High profiles defined in the fidelity range extensions AVS China Profiles 13 Dirac Wavelet Transforms 8 More efficient than block transforms with still images Operates on entire picture Logarithmic frequency decomposition into sub bands at each stage the filter produces for sub bands called Low Low LL Low High LH High Low HL and HighHigh HH The LL band is iteratively encoded to gain the required data Wavelet transforms have been proven to provide a more efficient technique than block transforms with still images and is currently used in JPEG2000 Horizontal and vertical filtering for 2D signals Parametric Comparison Algorithmic Element H 264 AVC 1 Dirac 9 AVS China Part 7 14 Intra Prediction 4x4spatial 16x16 spatial I PCM 4x4 spatial 9 modes simple 4x4 intra prediction and direct intra prediction Transform 4 4 integer DCT 8 8 integer DCT 4 4 wavelet transform 4x4 ICT without scaling in decoder In Loop Filters Deblocking None Deblocking Entropy Coding CAVLC Context Length CABAC Context Arithmetic VLC P Frame Type Adaptive Single reference Multiple references Adaptive Variable VLC 2D VLC E g Golomb code Binary Single reference Multiple references Motion compensation 16 16 16 8 8 16 8 8 8 4 4 8 4 4 block size 4 4 Single reference Multiple references maximum of 2 reference frames 16 16 16 8 8 16 8 8 CIF and QCIF formats 3 Fig a Common Intermediate Format CIF 4 2 0 chroma sampling Fig b Quadrature Common Intermediate Format QCIF 4 2 0 chroma sampling Performance Analysis of Dirac Video Codec Original File News yuv Format 4 2 0 DIRAC Codec QCIF sequence news qcif yuv Height 176 Width 144 Total no of frames 300 Frames used 100 Original File size 3713KB Frame Rate 25 fps Quality Factor QF Compresse d File Size KB Bit rate KBps YPSNR dB Y MSE Y SSIM Compressi on Ratio 0 18 4 58 23 0236 326 68 0 693 3 206 1 3 32 8 152 27 965 104 71 0 854 3 4 116 1 5 59 14 989 32 364 38 027 0 925 63 1 8 166 42 426 41 949 4 184 0 984 9 22 1 10 373 95 388 46 699 1 401 0 993 10 1 Video Quality at different values of Quality Factor QF QF 5 QF 0 DIRAC codec File news yuv Format QCIF QF 10 DIRAC Codec CIF sequence news cif yuv Height 352 Width 288 Total no of frames 300 Frames used 100 Original File size 14 850KB Frame Rate 25 fps Quality Factor QF Compresse d File Size KB Bit rate KBps YPSNR dB Y MSE Y SSIM Compressi on Ratio 0 38 9 473 25 383 189 73 0 78 390 1 3 81 20 66 30 675 56 104 0 8973 183 1 5 159 40 567 35 248 19 573 0 946 93 1 8 524 134 44 42 611 3 592 0 9802 28 1 10 1379 352 95 46 67 1 41 0 99 10 1 Video Quality at different values of Quality Factor QF QF 5 QF 0 DIRAC codec File news yuv Format CIF QF 10 DIRAC Codec File News yuv Format 4 2 0 DIRAC Codec File News yuv Format 4 2 0 Original File Foreman yuv Format 4 2 0 DIRAC Codec QCIF sequence foreman qcif yuv Height 176 Width 144 Total no of frames 300 Frames used 100 Original File size 3713KB Frame Rate 25 fps Quality Factor QF Compresse d File Size KB Bit rate KBps YPSNR dB Y MSE Y SSIM 0 24 6 1125 23 4 299 55 …
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