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New Low Complexity DCT Based Video Compression Method. International Conference on Telecommunications, 2009. ICT '09 . Tarek Ouni Walid Ayedi Mohamed Abid National ENGineering school of sfax. Outline. Introduction DCT based coding method Proposed method Experiments Conclusion. - PowerPoint PPT Presentation
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IN TER N ATIO N A L C O N F ER EN C E O N TELEC O M M U N IC AT IO N S, 2 00 9 . IC T ' 09 .
TA R EK O U N IWA L ID AY ED I
M O H A M ED A BID
N ATIO N A L EN G IN EER IN G SC H OO L O F S FA X
New Low Complexity DCT Based Video Compression Method
Outline
IntroductionDCT based coding methodProposed methodExperimentsConclusion
Introduction
Video 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 efficiency with minimum processing complexity
Introduction
This 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 compaction high video compression ratio
Introduction
The proposed method is efficient especially in high bit rate and with slow motion video.
The proposed method is suitable for video surveillance applications embedded video compression systems
Problem
Motion estimation process is computationally intensive. stored video applications. off-line on powerful computers.
Not appropriate to be implemented as a real-time for video surveillance camera fully digital video camera
Solution
Improve compression efficiency Temporal redundancies are more relevant than spatial one. Exploiting more redundancies in the temporal domain can achieve
more efficient compression.
Minimize processing complexity 3D transform produces video compression ratio
close to the motion estimation based. less complex processing. exploit temporal redundancy.
Outline
IntroductionDCT based coding methodProposed methodExperimentsConclusion
DCT based coding method
Compression energy compaction
DCT based coding method
Undesirable effects1. graininess2. blurring3. blocking artifacts
3D-DCT coding method
The 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.
3D-DCT coding method
In 3-D transform coding based on the DCT, the video is first divided into blocks of M N K pixels. M : horizontal dimension N : vertical dimension K : temporal dimension
Treat video as a succession of 3D blocks or video cubes.
3D-DCT coding method
3-D transform coding method Advantage :
1. do not require the computationally intensive process of motion estimation.
Disadvantage : 1. requires K frame memories both at the encoder and decoder to
buffer the frames.
3D-DCT coding method
3-D based coder v.s Motion compensated coder 3-D based coder :
high compression ratio lower complexity
The proposed method puts in priority the exploitation of temporal redundancy. temporal is more important than spatial.
Outline
IntroductionDCT based coding methodProposed methodExperimentsConclusion
Proposed method
Basic 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 method
The proposed method step : input the video cube. decompose into temporal frames. gather into one big frame. coding the obtained big frame.
Proposed method
A. Hypothesis many 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
spatial
temporal
Proposed method
B. Accordion based representation temporal and spatial decomposition of video cube.
1
32
4
43 2
1
Proposed method
Proposed method
C. Accordion analytic representation input the GOP frames and output the resulting frame IACC
inverse process :
Proposed method
D. Coding ACC-JPEG decompose 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).
Outline
IntroductionDCT based coding methodProposed methodExperimentsConclusion
Experiments
A. Parameters of the representation
Experiments
B. Compression performance
Experiments
C. ACC-JPEG artifacts
Experiments
Compare to MPEG-4
Outline
IntroductionDCT based coding methodProposed methodExperimentsConclusion
Conclusion
Feature analysis Symmetry Simplicity Objectivity Flexibility
Exploits 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.�