Study and Comparison of MPEG-2 and H.264 main profiles and available transcoding methodsIntroductionMPEG-2MPEG-2 ProfilesMPEG-2 Encoder [10]MPEG-2 Encoder (contd.)MPEG-2 Decoder [7]H.264H.264 Profiles – Comparison [11]H.264 Profiles – Coding parts [1]H.264 Encoder[9]H.264 EncoderH.264 Decoder [7]Comparison between H.264 and MPEG-2Comparison between H.264 and MPEG-2 (contd.)Performance comparison between H.264 and MPEG-2 – SimulationsPerformance comparison between H.264 and MPEG-2 –Simulation (Foreman)Performance comparison between H.264 and MPEG-2 –Simulation results (Foreman)Performance comparison between H.264 and MPEG-2 –Simulation (News)Performance comparison between H.264 and MPEG-2 –Simulation results (News)Performance comparison between H.264 and MPEG-2 –Simulation (Carphone)Performance comparison between H.264 and MPEG-2 –Simulation results (Carphone)Conclusions from simulationsTranscoding: IntroductionTranscoding: The criteriaTranscoding: Architectures [7,15] Open Loop TranscodingTranscoding: Architectures [7,15] Cascaded Pixel Domain TranscodingSlide 28Slide 29ReferencesReferences (contd.)Slide 32Study and Comparison of MPEG-2 and H.264 main profiles and available transcoding methodsEE 5359Priyanka Ankolekar1000 51 4497Introduction•Development of international video coding standards like MPEG-2 led to a boost in multimedia applications like digital video recording and teleconferencing.•On growing demand for better compression performance led to advanced video coding standards like H.264.•H.264 is superficially similar to MPEG-2•However, there are significant differences in the details.•This project aims to compare the MPEG-2 and H.264 main profiles and to discuss related transcoding methods.MPEG-2•Second of several standards developed by the moving pictures experts group [16].•Used as the format of digital TV signals and direct broadcast satellite TV systems.•MPEG-2 is not optimized for low bit rates like 1Mbps. But it outperforms MPEG-1 at 3Mbps and above.•It is used for higher data rates of 4Mbps (DVD) and 19Mbps (HDTV).•MPEG-2 devices are back compatible with MPEG-1.•MPEG-2/Video is formally known as ISO/IEC 13818-2 and as ITU-T Rec.H.262. [21].MPEG-2 ProfilesMPEG-2 Profiles[16]Abbr. NamePicture CodingTypesChromaFormatAspect Ratios Scalable modesSPSimpleprofileI, P 4:2:0square pixels, 4:3, or 16:9noneMP Main profile I, P, B 4:2:0square pixels, 4:3, or 16:9noneSNRSNRScalableprofileI, P, B 4:2:0square pixels, 4:3, or 16:9SNR (signal-to-noiseratio) scalableSpatialSpatiallyScalableprofileI, P, B 4:2:0square pixels, 4:3, or 16:9SNR- or spatialscalableHP High profile I, P, B4:2:2 or 4:2:0square pixels, 4:3, or 16:9SNR- or spatialscalableA profile is a collection of compression tools that together make up the coding system. A different profile means that a different set of compression tools is available. [22]There are five profiles in MPEG-2, as summarized below.MPEG-2 Encoder [10]MPEG-2 Encoder (contd.)•DCT: 2 dimensional 8x8 – for intra frames 8x8 pels – for inter frames 8x8 residual blocks•Quantizer: Quantizes DCT coefficients using a default or modified matrix.•Motion Estimation and Compensation:–In the motion estimation process, motion vectors for predicted and interpolated pictures are coded differentially between macroblocks. –For the motion compensation process integer and half pel resolution motion vectors are used to predict from previously decoded pictures. 8 16 19 22 26 27 29 3416 16 22 24 27 29 34 3719 22 26 27 29 34 34 3822 22 26 27 29 34 37 4022 26 27 29 32 35 40 4826 27 29 32 35 40 48 5826 27 29 34 38 46 56 6927 29 35 38 46 56 69 83MPEG-2 Decoder [7]H.264•Developed by the Joint Video Team (JVT).•Achieves MPEG-2 quality compression at almost half the bit rate [7].•Significant coding efficiency, simple syntax specifications, and seamless integration of video coding into all current protocols and multiplex architectures. •Supports various applications such as video broadcasting, video streaming, and video conferencing over fixed and wireless networks and over different transport protocols. [4]H.264 Profiles – Comparison [11]Baseline Extended Main HighI and P Slices Yes Yes Yes YesB Slices No Yes Yes YesSI and SP Slices No Yes No NoMultiple Reference Frames Yes Yes Yes YesIn-Loop Deblocking Filter Yes Yes Yes YesCAVLC Entropy Coding Yes Yes Yes YesCABAC Entropy Coding No No Yes YesFlexible Macroblock Ordering (FMO)Yes Yes No NoArbitrary Slice Ordering (ASO) Yes Yes No NoRedundant Slices (RS) Yes Yes No NoEach H.264 profile specifies a subset of entire bitstream of syntax and limits that shall be supported by all decoders conforming to that profile.There are three profiles in the first version: Baseline, Main and Extended. There are four High profiles defined in the fidelity range extensions [19].H.264 Profiles – Coding parts [1]H.264 Encoder[9]H.264 Encoder•4x4 integer DCT: Smaller blocksize leads to a significant reduction in ringing artifacts.•Quantization and scan: H.264 standard specifies the math formula for the quantization process.•Deblocking filter: To reduce the blocking artifacts in the block boundaries and to stop the propagation of accumulated coded noise. The filtered image is used in motion compensated prediction of future frames and helps achieve more compression. •Intra prediction: The encoder derives a predicted block based on its prediction with previously decoded samples (for I frames).•Inter prediction: –Performed on the basis of temporal correlation and consists of motion estimation and motion compensation. –Motion vector resolution is ¼ pel–Supports large number of block sizes –Multiple reference pictures (upto 32 previously coded frames).H.264 Decoder [7]Comparison between H.264 and MPEG-2Algorithm Characteristic MPEG-2 H.264General Motion compensated predictive, residual transformed, entropy codedSame basic structure as MPEGBlock size 8x816x16, 8x16, 16x8, 8x8, 4x8, 8x4, 4x4Macroblock size 16x16 (frame mode)16x8 (field mode)16x16Intra Prediction None Multi-direction, Multi-patternQuantizationScalar quantization with step size of constant incrementScalar quantization with step size of increase at the rate of 12.5%Entropy coding VLC CAVLC, CABACWeighted prediction No YesComparison between H.264 and MPEG-2 (contd.)Algorithm Characteristic MPEG-2 H.264Reference picture One picture Multiple picturesMotion Estimation Blocks
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