C-Cube CL550 JPEG Image Coprocessor - Hot Chips
C-Cube CL550 JPEG Image Coprocessor - Hot Chips
C-Cube CL550 JPEG Image Coprocessor - Hot Chips
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I Introduction<br />
I The<br />
2<br />
C-<strong>Cube</strong> <strong>CL550</strong><br />
<strong>JPEG</strong> <strong>Image</strong> <strong>Coprocessor</strong><br />
Problem<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
An 8.5" x 11" Color Picture is 25 MBytes<br />
One Full • Color Frame is 1 MByte<br />
One Second of Motion Video is 30 MBytes<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811190<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811/90
I Design<br />
3<br />
Goal<br />
Symmetric Compression I Decompression<br />
CCITI I ISO Int'l Standard<br />
All <strong>Image</strong> types : Still and Motion<br />
I.._p_e_rf_o_r_m_a_n_c_e _<br />
4<br />
In SIW 1 MByte <strong>Image</strong><br />
In HIW 1 MByte <strong>Image</strong><br />
<strong>CL550</strong> 1 MByte <strong>Image</strong><br />
Several Minutes<br />
Several Seconds<br />
1/30th of a Second<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811/90<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811190
5<br />
CCITT / ISO Int'l Standards<br />
Facsimile<br />
<strong>Image</strong><br />
Motion<br />
Grp. 3 & 4<br />
<strong>JPEG</strong><br />
MPEG<br />
I <strong>JPEG</strong> Standard<br />
6<br />
CCITISGVIII:<br />
Terminal<br />
Characteristics<br />
and Protocols<br />
Facsimile<br />
New <strong>Image</strong><br />
ommunicatio<br />
Group (NIC)<br />
Document<br />
Architecture<br />
Phototelegraphy<br />
Teleconferencing<br />
Videotex<br />
CCITI SG XV: Videophone<br />
& Videoconference<br />
Service<br />
1984<br />
1990<br />
1992<br />
Joint<br />
Photographic<br />
Expert Group<br />
(<strong>JPEG</strong>)<br />
Joint Bi-Ievel<br />
<strong>Image</strong> Group<br />
(JBIG)<br />
Stephen Purcell<br />
e-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
8/1/90<br />
ISO IEC/JCTC1/SC2IWG8 Coded<br />
RepresentationOf Picture<br />
and Audio Information<br />
Digital Audo & Picture<br />
Architecture (DAPA)<br />
DAPA<br />
Architecture<br />
Photograph<br />
in<br />
Computer Graphics<br />
Coding<br />
Audio coding<br />
Moving Picture<br />
Coding<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
8/1/90
I <strong>Image</strong><br />
7<br />
Quality<br />
No Degradation on Screen <strong>Image</strong>s at 10 : 1<br />
No Degradation on Print <strong>Image</strong>s at 25 : 1<br />
1..._J_P_EG_B_I_O_Ck_D_ia_g_ra_m__<br />
8-Line<br />
Strip·<br />
Buffer<br />
8<br />
Stephen Purcell<br />
c-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811/90<br />
, .<br />
Color<br />
Conversion<br />
RGe'" .YUV<br />
DCl flDCl<br />
Quantizer<br />
Coder f<br />
Decoder<br />
' - _ .<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811/90
I Baseline<br />
9<br />
System<br />
Input Picture<br />
I_Y_'_C_b_'_c_r_c_o_lo_r_s_p_a_c_e__<br />
10<br />
V<br />
Cb =<br />
Cv<br />
Output Picture<br />
0.299<br />
-0.169<br />
0.500<br />
Stephen Purcell<br />
c-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
8/1/90<br />
0.587 0.114<br />
-0.332 0.500<br />
0.419 -0.081<br />
Luminance, Chrominance better than RGB or CMY<br />
Less correlation between components ==> better coding<br />
Human eye is more sensitive to luma than chroma<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
8/1190<br />
R<br />
G<br />
B
11<br />
Discrete Cosine Transform<br />
Real, orthogonal transform<br />
related to Discrete Fourier Transform<br />
Spatial ==> Frequency<br />
Frequency dependent Quantization<br />
Correlated ==> Uncorrelated<br />
Independent entropy coding of coefficients<br />
I Quantization<br />
12<br />
Uniform Quantization of transform coefficients<br />
Stephen Purcell<br />
e-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811/90<br />
More low frequency buckets; less high frequency<br />
Human eye resolves better at low frequency<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811/90
15<br />
16<br />
AC Coefficient Coding<br />
Code (ZRU<br />
R:: R - 16<br />
2-D Value Array for AC Coef VLCs<br />
NNNN<br />
Length •<br />
of<br />
Zero<br />
Run<br />
o EOB<br />
IS<br />
ZRL<br />
Code (EOB)<br />
C Done J<br />
SSSS - Size of Non-Zero AC Coef<br />
o 1 10 11 ...IS<br />
Stephen Purcell<br />
c-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811190<br />
Stephen Purcell<br />
c-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811190
17<br />
I <strong>CL550</strong><br />
18<br />
Where is the compression?<br />
Chroma subsampling (2x, lossy)<br />
Transform (1x, lossless)<br />
Quantization (5x, lossy)<br />
Entropy Coding (2x, lossless)<br />
<strong>JPEG</strong> <strong>Image</strong> Compression Processor<br />
Single chip compression/decompression<br />
Adjustable compression ratio 8:1 to 100:1<br />
24-bit RGB and VUV color formats<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811190<br />
Real-time CCIR 601 Video bandwidth (14M pixels/sec)<br />
Stephen Purcell<br />
C-<strong>Cube</strong> Microsystems<br />
<strong>Hot</strong> <strong>Chips</strong> Symposium<br />
811190
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