1. Case Study ARM Platform-based JPEG Codec HW/SW Co-design
Teaching Assistant : Yu-Ju Cho
Advisor : Prof. An-Yeu Wu

2. Outline
Introduction to JPEG Codec
Lab ─ Case study
Reference

3. ISO/IEC 10918-1 JPEG JPEG: Joint Photographic Experts Group
JPEG voted as international standard in 1994
JPEG standard has four compression method
Baseline sequential DCT-based coding
Progressive DCT-based coding
Lossless coding method
Sampling and Quantization are not considered at loss-less coding scheme
Hierarchical coding method

4. Baseline sequential V.S. Progressive DCT-based coding
Compression Method T I S O 7 3 - 9 / d
Baseline sequential V.S. Progressive DCT-based coding

5. Block Diagram of JPEG Encoder
R G B
Y Cb Cr …
DPCM: Differential Pulse Code
Modulation
RLC: Run-Length Code

6. Color Model in Video ─ YCrCb
Y: Luminance
Cb,Cr: Chrominance
YCbCr color model is used in JPEG and MPEG

7. Color Model in Video ─ YCrCb
CCIR-601 transform formula
Color space transform is loss-less

8. Chroma Sub-sampling
4:1:1 and 4:2:0 are mostly used in JPEG and MPEG

9. Block Diagram of JPEG Encoder
R G B
Y Cb Cr …
DPCM: Differential Pulse Code
Modulation
RLC: Run-Length Code

10. 2-D DCT (Discrete Cosine Transform)
Frequency domain
Space domain

11. Basis Image of 2-D DCT Horizontal Frequency Vertical Frequency Low
High
Vertical
Frequency
High

12. Frequency Distribution of 2-D DCT
By frequency:
By direction:

13. 8 point 1-D DCT Algorithm (1/2)
Better for VLSI design implementation!

14. 8 point 1-D DCT Algorithm (2/2)

15. Implementation 2-D DCT Example: row-column decomposition
Separable, row-column decomposition X
Transport
Memory
(Y) Z
1D DCT
Unit
1D DCT
Unit
Y=AX
Z=YAT

16. Block Diagram of JPEG Encoder
R G B
Y Cb Cr …
DPCM: Differential Pulse Code
Modulation
RLC: Run-Length Code

17. Quantization Table for Luminance16 11 10 24 40 51 61 12 14 19 26 58 60 55 13 67 69 56 17 22 29 87 80 62 18 37 68
109
103 77 35 64 81
104
113 92 49 78
121
120
101 72 95 98
112
100 99

18. Quantization Table for Chrominance17 18 24 47 99 21 26 66 56

19. Block Diagram of JPEG Encoder
R G B
Y Cb Cr …
DPCM: Differential Pulse Code
Modulation
RLC: Run-Length Code

20. Predictive Coding of DC Coefficients
Differential Pulse Code Modulation (DPCM)
To Store the differential value is better than the exact value.

21. Zig-zag Scan (AC Coefficients)

22. Run-Length Coding(RLC)DC
(R,L) => (0,-3)(0,-2)(0,-1)(0,-2)(0,-1)(2,-1)(EOB)

23. Huffman Coding for DC and AC Coefficient
(R,L) => (0,-3)(0,-2)(0,-1)(0,-2)(0,-1)(2,-1)(EOB)
Category
AC Coefficient Range 1
-1,1 2
-3,-2,2,3 3
-7,…,-4,4,…,7 4
-15,…,-8,8,…,15 5
-31,…,-16,16,…,31 6
-63,…,-32,32,…,63 7
-127,…,-64,64,…,127 8
-255,…,-128,128,…,255 9
-511,…,-256,256,…,511 10
-1023,…,-512,512,…,1023 11
-2047,…,-1024,1024,…,2047
(0,2)(-3),(0,2)(-2),(0,1)(-1),(0,2)(-2),…(0,0)
(Run,SSSS/Catagory)
Huffman Table

24. Huffman Coding for DC and AC Coefficient
Run/Size
Code length
Code word
0/0 (EOB) 14
1010
0/1 12 00
0/2 01
0/3 13
100
0/4
1011
0/5 15
11010
0/6 17
0/7 18
0/8 10
0/9 16
0/A
1/1
1100
1/2
11011
1/3
1/4 19
Category
Code length
Code word 10 2
000 11 3
010 12
011 13
100 14
101 15
110 16 4
1110 17 5
11110 18 6
111110 19 7 8 9
Table for luminance DC coefficient differences
Table for luminance AC coefficients
(0,2)(3),(0,2)(-2),(0,1)(-1),(0,2)(-2),…(0,0)
=>(01) (11) (01) (01) ……(1010)

25. An Example of Baseline DCT-based Coding
For Y, (8*8 pixels *8 bits/pixel = 512 bits)
FDCT
-128 Q
(6)(61),(0,2)(-3), (0,3)(4),(0,1)(-1), (0,3)(-4),(0,2)(2), (1,2)(2),(0,2)(-2), (0,2)(-2),(5,2)(2), (3,1)(1),(6,1)(-1), (2,1)(-1),(4,1)(-1), (7,1)(-1),(0,0)
Zig-Zag
(1110)(111101)(01)(00)(100)
(100)(00)(0)(100)(001)(01)
(10)(11011)(10)(01)(01)(01)
(01)( )(10)(111010)(1)( )(0)(11100)(0)
(111011)(0)( )(0)(1010)
Huffman
Run-length
total 102 bits
Q Table

26. Block Diagram of JPEG Encoder
R G B
Y Cb Cr …
DPCM: Differential Pulse Code
Modulation
RLC: Run-Length Code

27. Block Diagram of JPEG Decoder…

28. JPEG Bitstream

29. Outline
Introduction to JPEG Codec
Lab ─ Case study
Reference

30. File Structure

31. Read & Write Address FDCT IDCT Write_head 0xcc000000 0xcc000004
0xcc00000c
0xcc000010
0xcc000014
0xcc000018
0xcc00001c
Write_head
0xcc000040
0xcc000044
0xcc000048
0xcc00004c
0xcc000050
0xcc000054
0xcc000058
0xcc00005c
FDCT
IDCT
Read_head
0xcc000020
0xcc000024
0xcc000028
0xcc00002c
0xcc000030
0xcc000034
0xcc000038
0xcc00003c
Read_head
0xcc000060
0xcc000064
0xcc000068
0xcc00006c
0xcc000070
0xcc000074
0xcc000078
0xcc00007c

32. Result for SW Simulation
Original
Encoder
Decoder

33. Result for HW Simulation
Original
Encoder
Decoder

34. Profiling Result of SW Simulation

35. Lab ─ Case Study Goal Principles Requirement Discussion
Implement the JPEG codec system using ARM platform
Principles
Implement the ARM platform-based JPEG codec HW/SW co-design
Requirement
Analysis the profiling of pure software simulation
Explain how to partition the HW/SW of JPEG codec
Implement the JPEG codec with HW/SW co-design
Discussion
Explain where is the stack and heap ? And who initialize them

36. Outline
Introduction to JPEG Codec
Lab ─ Case study
Reference

37. Reference
Wen-Hsiung Chen, C. Harrison Smith, and S. C. Fralick, "A Fast Computational Algorithm for the Discrete Cosine Transform," IEEE Trans. Commun., vol. COM-25, pp , Sept 1977.
JPEG: Still Image Data Compression Standard by William B. Pennebaker and Joan L. Mitchell, Kluwer Academic Publishers, ISBN: