1. Arithmetic-Context Compression
Irina Bocharova, Kirill Yurkov,
Mikhail Bogdanov, Roman Bolshakov, Alexander Buslaev,
Yuri Konoplev, Anrew Tereskin, Oleg Finkelshteyn
autumn 2010 - spring 2011
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2. Agenda
Purpose
Schemes of Encoder and decoder
Encoding DC
Encoding RUN’s and AC
Arithmetic Levenstein codec
Results
Problems
Map of boundary blocks
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3. Purpose
Realize a recoder of JPEG to reduce bit stream
Requirements: bit-to-bit corrsepondense
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4. Scheme of encoder
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5. Scheme of decoder
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6. Encoding DC (DC Prediction)
B C
?
?
A X
DCC , |DCB − DCA | < |DCB − DCC |
P=
DCA , otherwise
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7. Encoding Run-lengths and AC (1)
here about RUN’s
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8. Encoding Run-lengths and AC (2)
and AC
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9. Arithmetic coding
Arith + Adaptive model
reference
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10. Levenstein code
Only Levenstein
reference
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11. Test images
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12. Result and Comparing
Picture.jpg Size PackJpg We (theory) We (practice)
A10 842 Kb 19.2 % 10.8 %
Afisha 213 Kb
Bird 82 Kb 17.7 % 16.8 %
Document 103 Kb 29.7 % 13.7 %
Flower 5 Kb
Monkey 30 Kb 30.5 % 26.8 %
Portrait 63 Kb
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13. Problems (1)
problem with parsing and bit-to-bit corrsepondense
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14. Problems (2)
problem with Arithmetic codec and Alphabet size
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15. Map of boundary blocks
Is it really necessary?
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16. Thanks
Questions ?
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17. References
links array
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