JPEG standard
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JPEG: “Joint Photographic Experts Group”
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Formally:
ISO/IEC JTC1/SC29/WG10
International
Organization for
Standardization
International
Electrotechnical
Commission
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Working Group 10
(JBIG, JPEG)
Joint ISO/IEC
Technical
Committee
(Information
Technology)
Subcommittee 29
(Coding of Audio,
Picture, Multimedia
and Hypermedia
Information)
Joint effort with CCITT (International Telephone and Telegraph
Consultative Committee, now ITU-T) Study Group VIII
Work commenced in 1986
International standard ISO/IEC 10918-1 and CCITT Rec. T.81 in 1992
Widely used for image exchange, WWW, and digital photography
Motion-JPEG is de facto standard for digital video editing
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 1
JPEG: image partition into 8x8 block
8x8 blocks
Padding of
right boundary
blocks
Padding of
lower boundary blocks
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 2
Baseline JPEG coder
DC Huffman
tables
dc quantization indices
input
image
Level
offset
8x8
DCT
Uniform
scalar
quantization
Differential
coding
Zig-zag
scan
Run-level
coding
VLC
Compressed
image data
VLC
ac quantization indices
Quantization
tables
Bernd Girod: EE398A Image and Video Compression
Compressed
image data
AC Huffman
tables
JPEG standard no. 3
Recommended quantization tables
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Based on psychovisual threshold experiments
Luminance
 Chrominance, subsampled 2:1
16
12
14
14
18
24
49
72
11
12
13
17
22
36
64
92
10
14
16
22
37
55
78
95
16
19
24
29
56
64
87
98
24
26
40
51
68
81
103
112
40
58
57
87
109
104
121
100
51
60
69
80
103
113
120
103
61
55
56
62
77
92
101
99
17
18
24
47
99
99
99
99
18
21
26
66
99
99
99
99
24
26
56
99
99
99
99
99
47
66
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
[JPEG Standard, Annex K]
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 4
intensity
contrast sensitivity (@ 500 cd/m2)
Contrast sensitivity of human vision
position
spatial frequency (cpd)
Bernd Girod: EE398A Image and Video Compression
L2  L1
contrast ratio
L2  L1
JPEG standard no. 5
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 6
Differential coding of DC coefficients
Q
DC
coefficients
+
-
VLC
VL
Decoder
One-block
delay
+
Q-1
+
One-block
delay
Encoder
Decoder
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 7
DC difference categories
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 8
Suggested Huffman code for DC differences
JPEG Standard, Table K3 - Luminance
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 9
JPEG run-level coding
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RRRR – four bits value specifying ac coefficient zero-run of
length 0…15
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SSSS – four bits specifying a range of magnitudes of the
following coefficient (“category”)
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Joint Huffman encoding for 8-bit value RRRRSSSS
Append bits for sign and exact magnitude
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 10
JPEG coefficient coding categories
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 11
JPEG suggested AC code for luminance
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 12
JPEG suggested AC code for luminance (cont.)
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 13
AC coefficient probabilities
Test image Lena
Default quantization matrix
• PMF decays more rapidly
for larger run lengths
• Almost independent of
bitrate (except EOB)
[Kingsbury, 2006]
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 14
AC coefficient probabilities (cont.)
Test image Lena
Default quantization matrix
• PMF decays more rapidly
for larger run lengths
• Almost independent of
bitrate (except EOB)
[Kingsbury, 2006]
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 15
JPEG compression results
231 kb, uncompressed, 320x240x3x8 bit
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 16
JPEG compression results
74 kb, compressed 3.24:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 17
JPEG compression results
51 kb, compressed 4.53:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 18
JPEG compression results
38 kb, compressed 6.08:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 19
JPEG compression results
31 kb, compressed 7.45:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 20
JPEG compression results
26 kb, compressed 8.88:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 21
JPEG compression results
22 kb, compressed 10.5:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 22
JPEG compression results
21 kb, compressed 11:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 23
JPEG compression results
18 kb, compressed 12.83:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 24
JPEG compression results
17 kb, compressed 13.59:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 25
JPEG compression results
15 kb, compressed 15.4:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 26
JPEG compression results
13 kb, compressed 17.77:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 27
JPEG compression results
11 kb, compressed 21:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 28
JPEG compression results
11 kb, compressed 21:1
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 29
Beyond Baseline JPEG
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Huffman code tables can be optionally replaced by
arithmetic coder (rarely supported)
Hierarchical mode for progressive image transmission
No predefined color spaces: up to 255 image components
Lossless mode: prediction with Huffman coding of residual
(not to be confused with JPEG-LS)
Additional information (e.g. date/time, camera, exposure,
aperture etc.) may be embedded into JPEG file
(e.g., EXIF, DCF used by digital cameras)
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 30
Reading
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Taubman, Marcellin, Chapter 19
G. K. Wallace, “The JPEG still picture compression
standard,” IEEE Trans. Consumer Electronics, vol. 38, no.
1, pp. xviii-xxxiv, Feb. 1992.
ITU-T Rec. T.81
Bernd Girod: EE398A Image and Video Compression
JPEG standard no. 31