Transmission
of various multimedia in communication networks is going to be widespread in
recent years. All this is possible thanks to the integration of information
networks and their globalization, the development of computer technology and
the emergence of the needs from various organizations and institutions,
business and commercial structures, individual users in access to new
multimedia services. New technologies is widely used now for informational and
cognitive, educational, scientific, business, administrative, commercial,
security or other human activities.
Communications
service providers encounter with a situation where users need not just access
to the Internet or even a dedicated high-speed communication channel, but a
whole range of services. The complex is to include services such as telephony,
data transmission, Internet access, video calls, watching various TV programs,
video "on demand", and more in a single package of telecommunication
services.
Full-scale
implementation of the above, depends on many factors, and primarily is
determined by the rate of introduction of new technologies and the convergence
of communication networks by means of transforming the network infrastructure
in the network and packet switching. The integrated communication services for
data transmission are formed by providing users with a number of certain
services:
-
traditional
voice services, data transmission and broadband Internet access;
-
video
telephony;
-
videoconferencing;
-
access
to broadcast-quality television programs;
-
video "on demand";
-
music
"on demand";
-
video
surveillance;
-
e-learning
through video calls from the central educational institutions and other
organizations for their branches;
-
telehealth
for treatment, observation and training of local medical staff;
-
various
informational and services, and others.
The
emergence of broadband connection, transition from analogue to digital
television, new advances in video compression and transmission, increase of
communicating channel bandwidth allow today to implement video calling (video
telephony and videoconferencing) with desired picture quality and sound.
Multimedia solutions consistent not only with natural forms of human
communication, but also the main trends of communication development. The
results of conducted studies showed that the normal telephone conversation
interlocutors perceive 10% of the total volume of transmitted information.
Possibility to speak and see the interlocutor can increase the information in 5
or even 6 times.
Currently
a number of practical schemes of video conference organization are known which
depend on the number of participants, the composition of used equipment, tasks,
and so on. In the function of communication channels conventional telephone
networks, local networks, ISDN, IP-networks, mixed-vendor networks can be used.
Video
conferencing system allows carrying out the following tasks:
-
conferencing
for representational and corporate objectives;
-
realization
of important remote meetings,
discussions and examinations (expertise);
-
realization
of scientific symposiums, international scientific and technical conferences,
demonstrations of the latest equipment and modern technology;
-
providing
a new level of business cooperation with partners within the same city, within
a single country or on the planetary scale;
-
providing
the opportunity for close people who are in different cities or in other
countries of the world to keep in touch.
Existing
means of cryptographic information protection can preserve the confidentiality
of the content of video conferencing sessions, which is very important in
management and business, operations of large companies with an extensive
network of branches and in other applications.
To
arrange a video communication between two users, different video phones can be
used, for example TelePhoSee WVP-2000, which are designed in accordance with the
international standards ITU-T H.323, that ensures reliable and high quality
work on the Internet. A connection of a user to an IP-network carried out
through Ethernet port. Analog telephone port (POTS) TelePhoSee
embedded into videophone allows you to connect to a telephone line or PBX
and use it as ordinary phone.
The
main technical and functional capabilities of various IP-videophones are:
-
completely
independent system of videoconferencing organization on IP-networks (Ethernet
port);
-
frame
rate up to 25 ... 30 frames per second, PAL or NTSC;
-
network
Interface: 10 Base T (RJ45) Ethernet with connectable to different routers,
including ADSL;
-
resolution:
Format QCIF 176.144, CIF 352.288 and 4CIF 704.576 pixels for still images
(H.261 Appendix D);
-
full
compliance with the international standards ITU-T H.323 (videoconferencing on IP
networks), supported video standards: H.261, H.263, Audio: G.711, G.722,
G.723.1, G.728;
-
integration
of multimedia applications: (data channel Proprietary or T.120) shared
"whiteboard", transmission of data files, saving and sending audio
and video messages;
-
echo
suppression and etc.
Exploitation of videophones with different
technical characteristics showed that it is possible to achieve an acceptable
image quality (up to 15 ... 25 frames / s, CIF) and sound (G.729) using
full-duplex bands of 384 kbit / s (set in configuration).
Dial-up is carried out within 3 ...
5 seconds. In cases of sudden movements of transmitted objects image
degradation isn’t observed. Color transfer and sound quality is good.
The
quality of video transmission is also important in video surveillance systems. Video
surveillance systems provide in the operator or automatic mode solution of many
problems of detection, control, measurement and selection of the particular
objects. According to information formed by video surveillance systems, unauthorized
access to facilities, monitoring the change in their state can be analyzed and
detected, also other special information problems could be resolved
Anything
can be an object of surveillance and control, for example an office, bank,
warehouse, parking place or gas station, house, apartments and so on.
The
main trend in the development of technology and telecommunications is network
construction on the basis of digital switching methods and data transmission. Now
for the digital communication channel it does not matter what is contained
within the transmitted signal - video, audio, or any other data. Digital
transmission system allows providing high noise immunity of transmitted
information and stability of signal transmission parameters. There is a tendency
of increasing share of packet switching networks, not only for telephone
traffic transmission, but also for expansion of possible
range of new video
information services
and in providing integrated communication services on IP-based networks.
Although the tactics of provision of new
IP-based services at this stage will be oriented only on high-yield member,
however, the main objective is to bring them to small and mid-sized business,
and even to the bulk user.
Providing video information services by
communication service providers, together with the existing communication
services will provide a logical extension of their spectrum and will determine
a new stage in the activities of leading telecommunication companies in the
coming years.