adv601lc Analog Devices, Inc., adv601lc Datasheet - Page 8

• Manufacturer Part Number: adv601lc
• Description: Ultralow Cost Video Codec
• Manufacturer: Analog Devices, Inc.

ADV601LC
Table II. ADV601LC Typical Quantization of Mallat Data
Block Data
Mallat
Blocks
39
40
41
36
33
30
34
35
37
38
31
32
27
24
21
25
26
28
29
22
23
18
12
20
19
17
16
14
13
11
10
NOTE
1
The Mallat block numbers, Bin Width factors, and Reciprocal Bin Width
factors in Table II correspond to the shading percent fill) of Mallat blocks in
Figure 8.
5
6
9
3
8
7
5
4
0
2
1
1
0000000000000000000000000000000000000000000000000000000000000000000(uncompressed)
57 Zeros (Compressed)
Bin Width
Factors
0x007F
0x009A
0x009A
0x00BE
0x00BE
0x00E4
0x00E6
0x00E6
0x00E6
0x00E6
0x0114
0x0114
0x0281
0x0281
0x0301
0x0306
0x0306
0x0306
0x0306
0x03A1
0x03A1
0x0A16
0x0A16
0x0C1A
0x0C2E
0x0C2E
0x0C2E
0x0C2E
0x0E9D
0x0E9D
0x1DDC
0x1DDC
0x23D5
0x2410
0x2410
0x2410
0x2410
0x2B46
0x2B46
0xA417
0xC62B
0xC62B
Table III. Uncompressed Versus Compressed Data Using Run-Length Coding
Reciprocal Bin
Width Factors
0x0810
0x06a6
0x06a6
0x0564
0x0564
0x047e
0x0474
0x0474
0x0474
0x0474
0x03b6
0x03b6
0x0199
0x0199
0x0155
0x0153
0x0153
0x0153
0x0153
0x011a
0x011a
0x0066
0x0066
0x0055
0x0054
0x0054
0x0054
0x0054
0x0046
0x0046
0x0022
0x0022
0x001d
0x001c
0x001c
0x001c
0x001c
0x0018
0x0018
0x0006
0x0005
0x0005
–8–
THE RUN LENGTH CODER AND HUFFMAN CODER
This block contains two types of entropy coders that achieve
mathematically loss-less compression: run length and Huffman.
The run-length coder looks for long strings of zeros and replaces
it with short hand symbols. Table III illustrates an example of
how compression is possible.
The Huffman coder is a digital compressor/decompressor that
can be used for compressing any type of digital data. Essentially,
an ideal Huffman coder creates a table of the most commonly
occurring code sequences (typically zero and small values near
zero) and then replaces those codes with some shorthand. The
ADV601LC employs three fixed Huffman tables; it does not
create tables.
The filters and the quantizer increase the number of zeros and
strings of zeros, which improves the performance of the entropy
coders. The higher the selected compression ratio, the more
zeros and small value sequences the quantizer needs to generate.
The transformed image in Figure 5 shows that the filter bank
concentrates zeros and small values in the higher frequency
blocks.
Encoding vs. Decoding
The decoding of compressed video follows the exact path as
encoding but in reverse order. There is no need to calculate Bin
Widths during decode because the Bin Width is stored in the
compressed image during encode.
PROGRAMMER’S MODEL
A host device configures the ADV601LC using the Host I/O
Port. The host reads from status registers and writes to control
registers through the Host I/O Port.
Register Name
Register Type (Indirect or Direct, Read or Write) and Address
Register Functional Description Text
Bit [#] or
Bit Range
[High:Low]
Table IV. Register Description Conventions
Bit or Bit Field Name and Usage Description
0 Action or Indication When Bit Is Cleared (Equals 0)
1 Action or Indication When Bit Is Set (Equals 1)
REV. 0