ADV611JST View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

ADV611JST

Closed Circuit TV Digital Video Codec

Analog Devices 

ADV611/ADV612

P8–P15 8

HARRIS

8115

CLK2

CLK2

VDATA (0–7)

VCLK

ADV611/ADV612

27MHz

PIXEL CLOCK GSC

Figure 20. Using the Harris 8115 Decoder

GETTING THE MOST OUT OF ADV611/ADV612

How Much Compression Can Be Expected

The ADV611/ADV612 can be used in applications where up

to 7500:1 compression is required. To express this in more

meaningful terms, a digitized NTSC video signal at 167 MBit/s

per second can be reduced to less than 25 kbits per second. To

achieve this performance, the following approach could be used:

1. Image Compressed to 250:1

2. Frame Rate Reduced to 1 frame per second (not uncommon

in CCTV applications)

3. Quality box size less than 1% of the total image size

4. Background contrast attenuated by 18 dB

The scenario described above used by Analog Devices on the

CCTVPIPE evaluation board as the splash-screen after power-

up. Video quality is subjective, and therefore, it is highly recom-

mended to perform a direct evaluation of the CCTVPIPE or the

ADV601 software codec to confirm that the compression per-

formance is appropriate for a given application.

While the ADV611/ADV612 can be used in very high compres-

sion applications as outlined above, it is equally suitable for full

resolution, 60 field per second visually loss-less applications.

Evaluation Board

There is a low cost stand-alone evaluation board for the ADV611

called the CCTVPIPE (see block diagram). The CCTVPIPE

provides a fast, simple, and low cost means of evaluating the

performance of the ADV611/ADV612 and it is very similar to

the evaluation board for the ADV601LC, the VideoPipe. The

CCTVPIPE is shipped with a small mouse to allow real-time

quality box control. The board is also shipped with a small

speaker to provide an audio alert signal when motion is detected

in the video image. All of the source code and schematics for the

CCTVPIPE are available from the Analog Devices Web site free

of charge (www.analog.com/wavelet).

The exact part number is ADV611-CCTVPIPE and it can be

purchased through any Analog Devices authorized sales channel.

A PCI card is available for the ADV601 called the “VideoLab,”

which is bitstream compatible with the ADV611/ADV612. See

the Analog Devices Web site for further details.

Software Codec

Analog Devices has created two types of software products for

cases where encoding or decoding in software are desirable.

• Bit Exact Codec – Nonreal-time bit exact encoder for

Windows® ’95 or ’98.

• MMX/DirectShow Player – Real-time playback for

Windows ’98 (PC monitor can be used to view the video

directly–no need for a dedicated TV monitor).

Field Rate Reduction

As demonstrated by the CCTVPIPE evaluation board, field

rates can be reduced to increase compression. The ADV611/

ADV612 allow this to be done in hardware (see register

descriptions).

Edge Enhancement and Detection

Since the ADV611/ADV612 filters the image into wavelet

subbands, edge information is isolated in the high pass blocks of

image data (see the Mallat diagram of the Analog Devices build-

ing in the ADV601LC data sheet for an illustration). By zeroing

the low pass blocks, the ADV611/ADV612 will preserve only

the high pass content of the image and thus enhance the edges

in the image. The CCTVPIPE has a mode that demonstrates

this feature. Furthermore, these blocks can be Huffman de-

coded and analyzed for edge detection purposes.

Motion Detection

There are two known means of implementing motion detection

with the ADV611/ADV612.

1. Compare the image statistics between fields of video. This is

the technique used on the CCTVPIPE for the motion detec-

tion demo.

2. Decode the smallest Mallat block (Block 39) and compare

one field to the next. Since these block are small (approximately

2400 pixels) the computational burden is much less than it

would be for the entire image. For comparative purposes, the

data samples in Block 39 contain only 1/1024th of the total

samples, or 1/512th the luminance samples. Please Contact

Analog Device, Inc. for information on how to implement

this technique with quality box placement.

SERIAL PORT

(SPORT) EZ-ICE RS-232

JP17

JP16

P1

Y/C

J2

CVBS

J11

CCIR-656

J12

+5VDC

J10

ADV611

CCTVPIPE

SAA7111

DRAM

ADV611

H/W RESET

ADSP-2185

H/W RESET

DRAM

ADV611

H/W RESET

ADV7175

SRAM

SRAM

ROM

PALS

PUSH

BUTTONS

Y/C

J8

CVBS

J7

CCIR-656

J13

Figure 21. ADV611 CCTVPIPE Block Diagram

Windows is a registered trademark of Microsoft Corporation.

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