Visual Data Compression for Multimedia Applications

1
Visual Data Compression for Multimedia
Applications

• Touradj Ebrahimi and Murat Kunt
• Proceedings of The IEEE, Vol. 86, No. 6,
• June 1998, pp. 11091125

2
Introduction

• A tutorial on major visual data-compression
  techniques.
• A list of references for further information on
  the details of each method.

3
Outline

• Compression scheme
• Still-Image Coding
• Video Coding
• Pre- And Postprocessing
• Standard
• Dynamic Coding of Visual Information
• Conclusions

4
Outline

• Compression scheme
• Still-Image Coding
• Video Coding
• Pre- And Postprocessing
• Standard
• Dynamic Coding of Visual Information
• Conclusions

5
Compression scheme

• Extracting most relevant features from the origin
  data
• Assigning bit words to every extracted message

6
Still-Image Coding

• Classification
• Waveform-Based
• A certain model on the statistics of pixels in an
  image.
• Second-Generation
• Attempt to decompose the data into visual
  primitives.
• Such as textures and contours
• Fractal-Based

7
Video Coding

• Classification
• Waveform-Based
• Object-Based
• Model-Based
• Fractal-Based

8
Video Coding

• Object-Based
• Three parameter
• Shape
• Textural content
• motion

9
Video Coding

• Object-Based
• Example MPEG 4, H.263 uses this principle with
  block based counter parts to increase
  interactivity

10
Video Coding

• Model-Based
• Seeking to represent the projected 2-D image of a
  3-D scene by a 2-D or 3-D model

11
Video Coding

• Modeling a persons face
• Adjust the 3-D model to the persons face image.
• Texture-map the face image into the wireframe
  model.

12
Outline

• Compression scheme
• Still-Image Coding
• Video Coding
• Pre- And Postprocessing
• Standard
• Dynamic Coding of Visual Information
• Conclusions

13
Pre- And Postprocessing

• Enhance the quality and remove the various noise.
• Blocking effect
• Ringing
• Blurring.
• Other application

14
Pre- And Postprocessing

15
Pre- And Postprocessing
Another example
16
Outline

• Compression scheme
• Still-Image Coding
• Video Coding
• Pre- And Postprocessing
• Standard
• Dynamic Coding of Visual Information
• Conclusions

17
Standard

• ISO and CCITT (now the ITU-T)
• For still image
• JPEG, JPEG2000
• For video
• MPEG, MPEG2, MPEG4, MPEG7
• For teleconferencing and video-telephony
• H.261, H.263, H.264

18
Standard

• JPEG

19
Standard

• MPEG-1
• I-frame (Intra frame)
• Coded method is similar to that of JPEG.
• P-frame (Predicted frame)
• B-frame (Bidirectional frame)

20
Standard

• Motion compensation
• Predictive

21
Standard

• Motion compensation
• Bidirectional
• IBBPBBPBBPBBIBBP

22
Standard

• MPEG-1

23
Standard

• MPEG-2

24
Standard

• MPEG-4
• object-base

25
Standard

• MPEG-4

26
Standard
27
Outline

• Compression scheme
• Still-Image Coding
• Video Coding
• Pre- And Postprocessing
• Standard
• Dynamic Coding of Visual Information
• Conclusions

28
Dynamic Coding of Visual Information

• Each application is characterized by
• The type of data to be processd
• Still image, video, stereo image, etc
• Nature of visual data
• Natural, synthetic, text, medical, graphic, etc.
• Targeted bit rate
• Low, medium, high
• Maximum admissible delay
• Ranging from real time to off-line
• The type of communication
• Point-to-point, point-to-multipoint,
  multipoint-to-multipoint
• A set of functionalities
• Scalability, object manipulation, progressive,
  etc.

29
Dynamic Coding of Visual Information

• No universal coding technique exist.
• Example
• Wavelet/subband textures
• Morphological method edges and
  contours
• Dynamic combination of multiple compression
  techniques within the same framework.

30
Dynamic Coding of Visual Information

• A scene description is made up of three
  components
• Specification of the scene segmentation
• Specification of the representation model
  associated to each region (this consists of a
  flag that informs the decoder with coding tools
  have been selected for a given region)
• The coding parameters associated to each region
  with respect to the selected representation model.

31
Dynamic Coding of Visual Information
32
Dynamic Coding of Visual Information
33
Outline

• Compression scheme
• Still-Image Coding
• Video Coding
• Pre- And Postprocessing
• Standard
• Dynamic Coding of Visual Information
• Conclusions

34
Conclusions

• The best compression scheme would strongly depend
  on the application requirements.
• To make the appropriate choice after identifying
  the needs of the applications.