Effect of Saturation Arithmetic on Sum of Absolute Difference (SAD) Computation in H.264Motion EstimationMotion Estimation – SADSaturation ArithmeticSaturation Arithmetic – SAD [1]Saturation Arithmetic – SAD [2]Project WorkQuestions?Effect of Saturation Arithmetic on Sum of Absolute Difference (SAD) Computation in H.264Venkata Suman SanikommuECE 734 Project PresentationMotion EstimationBlock matching between successive frames – video compressionFind the best matching block (Motion Vector)Motion vector will be used to reproduce the reference frameMotion vectors are found by calculating minimum SADMotion Estimation – SADSAD ComputationCompute (Ai – Bi) for all 16 x 16 pixels in the two blocks A and BDetermine which Ai – Bi is less than zero and produce the absolute value in that case, else produce Ai – BiPerform accumulate operation to all 16x16 absolute values.Saturation ArithmeticOverflowed values will be represented as maximum valuesUnsigned: 00…0h, FF…FhExample:6234h + E123h => FFFFh (saturated)Saturation Arithmetic – SAD [1]Use saturation arithmetic and limit the number of bits used to represent SAD valuesReduced computation complexityReduced bits for SADMight affect the quality of block matching and thus motion estimationSaturation Arithmetic – SAD [2]If min{SAD} is less than FF…FhDoes not affect motion estimationIf min{SAD} is greater than FF…FhAffects motion estimationSubset size for block matching increasesIncreased encoded file sizeWe have to randomly select one for motion estimationRandomly selected block might not be a best matchProject Work1) Modify H.264 SAD computation code for saturation arithmetic2) Compare the performance of H.264 video coding for modular arithmetic and Saturation arithmetic for different number of bits.3) What is the minimum number of bits required to successfully use saturation arithmetic?4) How frequently does the SAD value saturate for a given number of bits to represent?5) What is the effect of saturation on encoded file
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