TM
Virtual Components for the Converging World
Amphion continues to expand its family of application-focused ASVCs
1
See http://www.amphion.com for a current list of products
CS6400
Color Space Converters
The CS6400 series of color space converters are virtual component solutions for leading-edge image processing
applications. Capable of sustained data rates of over 180 mega-conversions/sec in an ASIC implementation and
95 mega-conversions/sec in FPGA, these color space converters are ideally matched to Amphion's other imaging
products such as the CS6100 series of JPEG products as part of a complete image processing system. The CS6400
products are available in both ASIC and programmable logic versions that have been handcrafted by Amphion
to deliver high performance with low-power and minimal silicon area.
COLOR SPACE CONVERSION
RGB is the standard color format for most digital video input and output devices, such as display monitors.
However, processing an image in the RGB color space, including operations such as sub-sampling and
compression, is frequently not the most efficient method. To speed up some processing steps many broadcast,
video and imaging standards (PAL/NTSC) use luminance and color difference video signals, such as YUV,
making a mechanism for converting between formats necessary.
Figure 1: Typical Digital Video Decoding Channel Containing CS6400
IMAGE
CAMERA
VIDEO
DECODER
COLOR
SPACE
CONVERTER
STRIP BUFFER
RASTER-BLOCK
CONVERTER
DCT
FEATURES
Converts television broadcast signal colors to
digital video colors (CS6411 and CS6421) or
digital video colors to broadcast signal colors
(CS6410 and CS6420)
Available for SoC, ASIC and FPGA
Internal precision coefficient width of 10 bits
One conversion every clock cycle
Low latency - 3 clock cycles
APPLICATIONS
Video output conversion to digital RGB
Image filtering
Machine vision
Video and still image processing
KEY METRICS AND
SPECIFICATIONS
Refer to Table 4 for details of metrics for the CS6400
series of color space converter cores.
2
CS6400
Color Space Converters
CS6400 SYMBOL AND
PIN DESCRIPTION
A representative symbol, with the signal names, is shown in Figure 2.
Unless otherwise stated all signals are active high and bit(0) is the
least significant bit.
Table 1 summarizes the signal functions
.
.
Figure 2: Core Schematic
D
A
CLK
RST
E
F
B
C
CS6400
Table 1: I/O Descriptions
Signal
I/O
Description
CS6410
CS6411
CS6420
CS6421
Clk
I
Core Clock, clock input
Reset
I
Core reset, Asynchronous reset that resets all registers to zero
A
I
Red color[7:0]
Luminance[7:0]
Red color[7:0]
Luminance[7:0]
B
I
Green color[7:0]
U color difference data[7:0] Green color[7:0]
Chroma red data[7:0]
C
I
Blue color[7:0]
V color difference data[8:0] Blue color[7:0]
Chroma blue data[7:0]
D
O
Luminance[7:0]
Red color[7:0]
Luminance[7:0]
Red color[7:0]
E
O
U color difference data[7:0] Green color[7:0]
Chroma red data[7:0]
Green color[7:0]
Fb
O
V color difference data[8:0] Blue color[7:0]
Chroma blue data[7:0]
Blue color[7:0]
3
TM
General Description
The CS6400 color space converters perform linear
transformations from one color space to another. Table 1
shows the members which make up the CS6400 family of
products. All members of the 6400 product family use 10-bit
coefficients in the core for all calculations with rounding
carried out at the outputs. All cores have both input and output
registers plus an additional pipeline cut allowing high speeds
to be achieved with a low latency of 3 clock cycles and a
throughput of 1 clock per cycle.
Figure 3 shows the internal operation of a generic converter.
Internal precision of 10 bits maintains accuracy of the 8 bit
output. Input and output colors as well as specific coefficient
values are given in Table 3.
Figure 3: Block diagram of generic color space converter
Table 2: 6400 Family of Cores
Product
Input Format
Output Format
CS6410
RGB
YUV
CS6411
YUV
RGB
CS6420
RGB
YCrCb
CS6421
YCrCb
RGB
C
B
A
8
C1
C2
C3
10
10
10
18
18
18
Offset 1
10
D
18
8
8
Rounding &
Saturation
8
18
8
C4
C5
C6
10
10
10
18
18
18
Offset 2
10
E
18
8
8
Rounding &
Saturation
8
18
8
C7
C8
C9
10
10
10
18
18
18
Offset 3
10
F
18
8
8
Rounding &
Saturation
8
18
4
CS6400
Color Space Converters
Table 3: Input and output colors with specific coefficient values
I/O
CS6410
CS6411
CS6420
CS6421
Color A
R
Y
R
Y
Color B
G
U
G
Cr
Color C
B
V
B
Cb
Color D
Y
R
Y
R
Color E
U
G
Cr
G
Color F
V
B
Cb
B
C1
0.299
1.140
0.257
1.164
C2
0.587
0
0.504
1.596
C3
0.114
1.140
0.098
0
Offset 1
0
0
16
-223
C4
-0.147
1
0.439
1.164
C5
-0.289
-0.394
-0.368
-0.813
C6
0.436
-0.581
-0.071
-0.392
Offset 2
0
0
128
136
C7
0.615
1
-0.148
1.164
C8
-0.515
-2.032
-0.291
0
C9
-0.100
0
0.439
2.017
Offset 3
0
0
128
-277
5
TM
TIMING DIAGRAMS
Figure 4 demonstrates only the functional timing for the core opera-
tion. A latency of 3 clock cycles can be observed.
Figure 4: Generic CS6400 Timing Diagram
AVAILABILITY AND IMPLEMENTATION INFORMATION
ASIC CORES
For applications that require the high performance, low cost and high integration of an ASIC, Amphion delivers a series of
multimedia ASVCs that are pre-optimized by Amphion experts to a targeted silicon technology. Choose from off-the-shelf versions
of the CS6400 family available for many popular ASIC and foundry silicon supplier technologies or Amphion can port the CS6400
to a technology of your choice.
FROGRAMMABLE LOGIC CORES
For ASIC prototyping or for projects requiring the fast time to market of a programmable logic solution, Amphion provide
programmable logic cores that offer the silicon-aware performance tuning found in all Amphion products, combined with the rapid
design times offered by today's leading programmable logic solutions.
D1
D2
D3
D4
D5
E1
E2
E3
E4
E5
F1
F2
F3
F4
F5
CLK
D
E
F
A1
A2
A3
A4
A5
B1
B2
B3
B4
B5
C1
C2
C3
C4
C5
A
B
C
Table 4: CS6400 Cores - Key Metrics
Product
Performance
SpartanTM-II
VirtexTM
VirtexTM-E
VirtexTM-2
CS6410
Area / Slices
222
222
222
222
Fmax / MHz
80
75
100
115
CS6411
Area / Slices
140
140
140
140
Fmax / MHz
65
75
90
105
CS6420
Area / Slices
204
204
204
204
Fmax / MHz
65
65
90
90
CS6421
Area / Slices
179
179
179
179
Fmax / MHz
65
75
95
105
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