New Low Complexity DCT Based Video Compression Method

New low complexity DCT based video compression method

International Conference on Telecommunications, 2009. ICT '09.

Tarek OuniWalid AyediMohamed Abid

National ENGineering school of sfaxNew Low Complexity DCT Based Video Compression MethodOutlineIntroductionDCT based coding methodProposed methodExperimentsConclusionIntroductionVideo signal has high temporal redundancies due to the high correlation between successive frames.

Current video compression technics are not suitable for exploiting this redundancy.

This paper presents a new video compression approach exploiting the temporal redundancy in the video frames. improve compression efficiencywith minimum processing complexityIntroductionThis paper consists on a 3D to 2D transformation of the video frames that allows exploring the temporal redundancy.avoiding the computational MC step.

The transformation turns the spatial-temporal correlation into high spatial correlation.e.g, transforms each group of pictures to one picture

Decorrelation of the resulting pictures by the DCT energy compactionhigh video compression ratioIntroductionThe proposed method is efficient especially in high bit rate and with slow motion video.

The proposed method is suitable for video surveillance applicationsembedded video compression systemsProblemMotion estimation process is computationally intensive.stored video applications.off-line on powerful computers.

Not appropriate to be implemented as a real-time forvideo surveillance camerafully digital video cameraSolutionImprove compression efficiencyTemporal redundancies are more relevant than spatial one.Exploiting more redundancies in the temporal domain can achieve more efficient compression.

Minimize processing complexity3D transform produces video compression ratio close to the motion estimation based.less complex processing.exploit temporal redundancy.OutlineIntroductionDCT based coding methodProposed methodExperimentsConclusionDCT based coding methodCompressionenergy compaction

DCT based coding methodUndesirable effectsgraininessblurringblocking artifacts

3D-DCT coding methodThe 2D-DCT has the potential of easy extension into the third dimension.e.g, 3D-DCT

3D-DCT includes the time as third dimension into the transformation and energy compaction process.

113D-DCT coding methodIn 3-D transform coding based on the DCT, the video is first divided into blocks of M N K pixels.M : horizontal dimensionN : vertical dimensionK : temporal dimension

Treat video as a succession of 3D blocks or video cubes.

3D-DCT coding method3-D transform coding methodAdvantage : do not require the computationally intensive process of motion estimation.

Disadvantage : requires K frame memories both at the encoder and decoder to buffer the frames.

3D-DCT coding method3-D based coder v.s Motion compensated coder 3-D based coder : high compression ratiolower complexity

The proposed method puts in priority the exploitation of temporal redundancy.temporal is more important than spatial.

OutlineIntroductionDCT based coding methodProposed methodExperimentsConclusionProposed methodBasic idea is to represent video data with high correlated form.projecting temporal redundancy of each group of pictures into spatial domain.

Combining them with spatial redundancy in one representation with high spatial correlation.

The obtained representation will be compressed as still image with JPEG coder.

Proposed methodThe proposed method step : input the video cube.decompose into temporal frames.gather into one big frame.coding the obtained big frame.

Proposed methodHypothesismany experiences had proved that the variation is much less in the temporal dimension than the spatial one.

pixels, in 3D video signal, are more correlated in temporal domain than in spatial one.

Expression :

Proposed method

spatialtemporalProposed methodAccordion based representationtemporal and spatial decomposition of video cube.

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Proposed method

Proposed methodAccordion analytic representationinput the GOP frames and output the resulting frame IACC

inverse process :

Proposed methodCoding ACC-JPEGdecompose the "IACC" frame into 8x8 blocks.

for each 8x8 block : Discrete cosine Transformation (DCT).Quantification of the obtained coefficients.Course in Zigzag of the quantized coefficients.Entropic Coding of the coefficients (RLE, Huffman).

OutlineIntroductionDCT based coding methodProposed methodExperimentsConclusionExperimentsParameters of the representation

ExperimentsCompression performance

ExperimentsACC-JPEG artifacts

ExperimentsCompare to MPEG-4

OutlineIntroductionDCT based coding methodProposed methodExperimentsConclusionConclusionFeature analysisSymmetrySimplicityObjectivityFlexibilityExploits temporal redundancy with the minimum of processing complexity is suitable in video embedded systems or video surveillance.Worst compression performance with non-uniform and fast motion sequence.