Based
on the DM642 digital signal processor from Texas Instruments, Inc. , the MPEG4x4
board from Teldat Security endows your VisorNET unit with MPEG4 video
compression capabilities for all four cameras, offering up to 30 frames per
second of high quality CIF size images on each of the cameras.
Key
characteristics
1.
Support for 4 composite video signal inputs.
2.
Up to 8 independent and simultaneous MPEG4 video
streams.
3.
Simultaneous transmission and recording in MPEG4 format
for each camera: The board supports different bit rates and
qualities per camera and per functionality, allowing different parameter for
recording and / or transmitting.
4.
Support
for high resolution formats of
up to 704x576 pixels (PAL) and 640x480
pixels (NTSC).
5.
Programmable
bandwidth from
9.6 kbps to 1 Mbps.
6.
One
composite video output for local viewing of
images with three different modes of operation: Camera pass-through,
auto-switching and 4 camera quadrant.
7. Full duplex two way audio communication using voice over IP technology and with a built in audio multiplexer to select between 4 possible audio inputs/outputs.
Block
diagram for the VisorNET MPEG4x4 expansion board
Technical specifications
§
4 analog composite video inputs and 1 analog composite
video output (1Vpp / 75 W, BNC connectors)
§
4 audio inputs/outputs (700 mV RMS, 300Hz-4kHz
bandwidth, RCA connectors)
§
64 Mbytes of RAM memory
§
1 DM642 digital signal processor running at 600 MHz
§
4
composite video decoders PAL/NTSC TVP5150 and 1 composite video codec PAL/NTSC
SAA7120
§
1
audio codec AC483
NOTE: The MPEG4x4 expansion board is included by
default in all VisorNET PRO configurations.
Description
Teldat
Security’s MPEG4x4 expansion board for VisorNET has been designed to offer
optimum performance for MPEG4 video compression on all 4 video inputs of a
VisorNET unit.
The
DM642 digital signal processor (DSP) from Texas Instruments, with more than 4800
MIPS (million of instructions per second) of processing power, is one of the
industry leading processors and is ideal for video processing applications, as
it includes in one single chip specialized peripherals that interface directly
with the analog to digital video converters.
The
DM642 can process up to eight simultaneous video streams (two per camera) in
MPEG4 simple profile format (fully compatible with the MPEG4 international
Standard). It is capable of processing a total of 120 images per second in CIF
size, allowing for frame rates of up to 30 images per second per camera. The bit
rate to use for each stream is fully programmable, ranking from 9 kbps to up to
1Mbps.
The
MPEG4x4 board has a composite video output through which it is possible to
locally monitor any of the input video signals connected to the VisorNET unit.
The video output, which can be connected locally to a monitor or to any device
with an analog video input, can be programmed in three different modes: direct
output of any of the four video inputs, automatic switching through all four
video inputs and a four camera quadrant mode.
As
an option, the MPEG4x4 board can be equipped with a AC843 processor from
AudioCodes. Such processor runs a G.723.1 audio codec which is used by the H.323
stack in the VisorNET unit when performing two way audio operations. The MPEG4x4
board has four audio inputs/outputs and a dual 4-to-1 multiplexer that allows
the selection of any of the four channels for its transmission and communication
with the VisorCENTRAL software.
Applications
The
MPEG4x4 board is specially designed for tele-surveillance applications in which
simultaneous viewing of several cameras is needed. Typical bandwidths for this
kina of application Hill vary from 50 to 300 Kbps per camera. For this kind of
scenarios, the MPEG4x4 offers cutting edge performance and one of the industries
best bandwidth/frame rate ratios.
The
MPEG4x4 characteristics and performance make it also ideal for digital video
recording applications as it offers one of the highest ratios of compression
available nowadays. The MPEG4 compression format used by the MPEG4x4 expansion
board will save a huge amount of storage space, thus decreasing the amount of
investment in recording media (hard drives, etc...).
Performance
Average
frame rate performance at CIF size (352x288 pixels) measured at several
bandwidths with and amount of movement (image variations) between 15 and 25%:
Available
functionalities per operation mode
The following chart presents the board’s functionalities† that are automatically made available according to the number of codecs that are running simultaneously on the board.
† Some functions are automatically enabled or disabled according to the number of active codecs at any time.
‡ For frame rates between 25 and 30 images bandwidth should be set to values of 300Kbps or higher.