VideoCompressionPInter-blockprediction:motionvectors
Inter-block prediction: motion vectors Video Compression
MPEG-4 Part 2, VisualPGlobal motion estimationNew The same set of parameters are used for the entire image Alternatively used with the local motion compensation in order tominimize the prediction error1to4MVs(andtheirpositions)perframetotransmitatdecoder,interpolationforeachMBVery useful for camera motion
Global motion estimation MPEG-4 Part 2, Visual Very useful for camera motion The same set of parameters are used for the entire image Alternatively used with the local motion compensation in order to minimize the prediction error 1 to 4 MVs (and their positions) per frame to transmit at decoder, interpolation for each MB New
MPEG-4Part2.VisualPDirect modeforbidirectional compensation葉 Withrespectto a pastreference(backwardMc) With respectto a futurereference (forwardMC) With respect to a reference given by the the average of a past and afutureone(bidirectionalMC)DirectmodeMV,=[(t.-t)/(t,-t)*MV+MV,MMVFBMVB=MV,-MVMVBPBP
Direct mode for bidirectional compensation MPEG-4 Part 2, Visual With respect to a past reference (backward MC) With respect to a future reference (forward MC) With respect to a reference given by the the average of a past and a future one (bidirectional MC) Direct mode New P P B B MV MV F MV B MV F=[(t c-t f)/(t b-t f)]*MV+MV D MV B=MV F-MV
MPEG-4Part2.VisualPPredictionmodule:block schemeCurrentframeMotionestimationMotionReferenceframe(s)compensationMotionvectors
Prediction module: block scheme MPEG-4 Part 2, Visual Current frame Reference frame(s) Motion estimation + - Motion vectorsMotion compensation
Signal CompressionGeneral Coding ArchitectureEncodingPredictionEntropyTransformyCodingQuantizationTECDecoding
General Coding Architecture Signal Compression Prediction Transform Quantization Entropy Coding