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| Video server and its applications in the field of television
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With video compression technology continues to improve and the development of
computer technology, video server has been widely used in the television
broadcast system, video server in a multi-channel broadcast system in a
comprehensive application, to make it a television broadcast system in the most
important group As part of the product can greatly improve the efficiency of
broadcast television. In fact, the video server also has many of the traditional
video surveillance equipment do not have the advantage, but also developed many
new application form. (Monitoring the field)
First, the
concept of video server
Video Server is a kind of video and audio data
compression, storage and handling of special computer equipment, its ad spots,
multi-channel broadcast cycle pad, delay broadcast, hard disk and video on
demand broadcast such areas have a wide range of applications . Video server
using M-JPEG or MPEG-2 compression format, and so on, with technical indicators
in the case of the video data compression, storage and transmission to meet the
requirements. It uses SCSI interface hard disk drives or FC interface as the
online video and audio data memory. A multi-channel input and output,
multi-format video and audio interface. Can be equipped with SCSI, FC, such as
network interface network, and video and audio data transmission and sharing.
Second, the composition of video server
Network Video Server is a
compression, storage, handling video and audio data for the computer, audio and
video compression by the encoder, large-capacity storage devices, input / output
channels, network interface, video and audio interface, RS422 serial interface,
the interface agreement , Software interface, video and audio, such as a
cross-point matrix, at the same time, providing the lock-in and video processing
functions.
Video and Audio Coding: As digital video, data of great, it
wants to use mature compression technology, video data to meet the technical
requirements of the target under the conditions of a high compression ratio of
compression, storage and transmission to meet demand. At present the general use
of video servers H.264 or MPEG-4 compression, and so on, users can choose
compressed according to the actual situation and the compression rate structure
to fit in a variety of broadcast occasions, both to save disk space, a program
to increase storage Volume, can guarantee that broadcast quality.
Large-capacity storage devices: video servers use high-speed, broadband SCSI
interface hard drive or FC interface of the most advanced video and audio
material as a hard disk storage medium. At the same time as the drive to expand
audio data is also more flexible.
Input / output channels: video server
with multi-channel input / output system, so that multiple entry, can play at
the same time, and multi-task.
Network Interface: Video servers with a
network interface to facilitate networking and data sharing. General video
servers with FC and Ethernet interface. FC fiber optic network using IP protocol
between the video server as a rapid, real-time copy of the exchange of material
and mobile networks, Ethernet for the transmission of data and control of state
inspection information.
As audio interface: Video servers are a
standard interface and analog video and audio surveillance video interface to
facilitate the passage of the surveillance video signals. Input / output signals
in the simulation, component and SDI choose.
RS422 serial interface:
video servers with multiple RS422 serial communication ports, each port can be
adopted by external RS422 communication line computer control to achieve record
and playback.
Agreement Interface: In addition to providing all kinds
of video server hardware interface control, the agreement also provided
interface. In addition to supporting RS422 interfaces such as the Profile RS422
agreement, but also support Louth, Odetics, BVW, and so on through the RS422
control agreement.
Software interface: video server to provide open
software interface for users or third-party manufacturers develop and build a
new application form.
Audio and video cross-point matrix: video server,
with visual, audio cross-point matrix, visual, audio channels scheduling
flexibility and a guaranteed Specifications not damaged.
In addition,
the lock-in video servers and video processing to facilitate the construction of
specialized applications as audio systems.
Third, the characteristics of
video server
Video Server with the traditional network equipment do not
have many characteristics of specific performance as follows:
(1)
Multi-channel, recording and playback feature set in one, the traditional
devices have more input and output of video and audio equipment is to switch
matrix, and a recording and playback of video equipment, self-evident, Video
server in the system can replace a number of video recorders and a small switch
matrix.
(2) video server used as a record of hard disk media,
non-linear features, so they have all the advantages of non-linear equipment,
such as material to find convenient material may be multiple output channels and
shared at the same time or may have been out of players.
(3) material
recorded in the hard drive has not yet form a complete document, can be
transferred from the output channel broadcast, which is very applicable to the
delayed broadcast and video on demand, and other fields.
(4) video
server easy to go forward or backward speed of the players, the traditional
video recorders to achieve this, to go through expensive special equipment.
4, video server applications in the field of television
As network
video server with the above-mentioned advantages, it will create many new
applications, to meet the needs of television media, and can greatly improve
productivity and reduce maintenance of equipment and manpower costs. Video
server in the field of television there were two main aspects: First, build
automatic use of broadcast video server systems; Second, the use of
video-on-demand video server.
1. Construction of automatic use of broadcast
video server system
The previous tape broadcast system is the main
medium, but as the video compression technology, continuous improvement and
development of computer technology in the use of broadcast video server system
has become possible and has many television stations in the domestic use, today
the establishment of The selection of broadcast video server system as a signal
source has become inevitable. To video servers as the main drive broadcast
system, give full play to the advantages of hard drive storage, to avoid the
result of video recorders and other equipment to broadcast the failure to bring
about the impact of multi-channel give full play to the superiority of the
sharing of resources, easily the various programmes Series for the broadcast and
various announcements, broadcast regularly between the control and management,
in the form of compressed files stored on the hard drive of the programme, can
be achieved without distortion preservation, all programmes from the production,
editing port on the set, thus simplifying the From production to broadcast the
work flow is conducive to enhancing efficiency.
The hard drive
broadcast system, digital compression program material is stored and broadcast.
System can be MPEG-2 or M-JPEG compression format.
Hard broadcast
system can be local storage, mirroring the way back up out of RAID drives.
RAID-1, also known as "mirroring", that is, using Double-Disc complete copy
methods to protect data and avoid the hard drive failures cause loss of data and
systems disruption, 100% of the redundancy can be achieved rapid restoration of
data. Each video server using a separate storage drive that is local storage,
video server completely Hubuganrao, and a fully mirror backup, system
reliability.
FC drives broadcast system can be combined with the dual
Ethernet network structure, use of FC transfer video and audio signals, using
Ethernet transmission control signal.
Hard by the video and audio
broadcast system servers, database servers, workstations acquisition,
pre-Supervisor workstations, workstations and other subsystems of broadcast. Two
audio server as a backup. Server through the fiber optic network
interconnection. The main server on the video and audio material through the
fiber optic network to Des Voeux copy on the server. Broadcasting from an
automated control system two sets of video and audio broadcast server
workstation simultaneously broadcast. This system is very reliable. At the same
time, the system set up according to different users different levels of
security, so that staff can not enter the system has nothing to do; effective
system to ensure data security, while the broadcast system, automatic locking a
variety of other illegal operations, promptly issued a warning signal.
To
video servers as the main drive system automatically broadcast the specific
application form as follows:
(1) automatically broadcast ads
Video
server for the first replay number and the time is short ad programs. In this
application form, the video server as an advertising broadcast special
equipment, controlled by the broadcast of the automatic control system software,
video servers from the broadcast can only assume in order to conduct a one, the
broadcast advertising material By advertising editor responsible for the control
of the computer, broadcast advertising in the order and control the scheduling
of ads broadcast by the computer, while the starting point and broadcast ads by
the end of the implementation of computer-controlled automatic broadcast
advertisements broadcast on the computer's control. Application of this method
does not need to have the broadcast system for big changes, the original
broadcast automatic control systems and software can continue to use, video
server here equivalent to more than one VCR (video servers depend on the number
of input channels ) And multiple Fangxiang Ji (depending on the video server's
output channel number). Therefore the original broadcast automatic control
system as the control software will be able to control video recorders, like the
server broadcast advertising.
(2) multi-channel broadcast system
automatically
The use of multi-channel video server can be established
cycle of sowing pad system for multiple channels of broadcast room to share. In
this application form, first of all the various channels of broadcast material
through the pad VTR entry to the video server, each room occupied channel
broadcast a video server output channels, video servers in all material can be
broadcast. In this application form, can use a configuration identical to the
establishment of broadcast video server systems. Lord, by the video server to
use a corresponding output channels, as a backup to each other's broadcast
channel, the main, between the video server by using optical fiber network (FC)
Internet, and share video and audio material, movement and reproduction, the
main guarantee , By the video server exactly the same material. Broadcasting
from an automated control system two sets of video servers for the broadcast
station broadcast simultaneously.
(3) TV broadcast system delay
Use
of video servers delay the establishment of television programmes broadcast
video server system is the use of the characteristics of the material that is
written into the hard drive, without a fully formed material documents the
circumstances, the call will be shared so that the broadcast system with the
so-called drive That is, in the play (to be slightly delayed after sowing)
functions. More appropriate in such a programme broadcast live programming
important. Will broadcast the first live recording drives, according to the need
to broadcast the live broadcast the appropriate time delay, the program director
and Supervision use of the time in the broadcast rate adjustment control
computer should not be broadcast live on the screen to cut and replaced with
other appropriate Material, or difficult to distinguish between the human eye to
a rate of 0.8 to 1.2 times as fast or slow player, so as to maintain the
corresponding time of late. This advanced technology means the basis of a
cover-up operation, can control the broadcast of inappropriate material, live
performance and not be affected.
The use of the hard disk video server
automatically broadcast system still has a variety of specific applications, not
itemized here compared to conventional broadcast the video, the drive system
automatically broadcast signals and material are not stored in cartridges, so
Pre-zero frame volumes, non-linear retrieval, material repeated use, sharing of
resources, and other advantages. Specific advantages are: improved efficiency,
with better security, the sharing of information resources and the advanced
nature of the system.
2. Use of video-on-demand video server
Video
on demand in two ways: Near Video on Demand (NVOD) and video-on-demand (VOD)
(1) Near Video on Demand (NVOD)
Video server is to achieve
quasi-video-on-demand (NVOD) Player of the core equipment, use of its
multi-channel features and characteristics of the material can be shared, to
achieve a programme of regular intervals, the viewer to be waiting for the
shortest period of time to watch their programs on demand. Such as: video server
within a length of the programme for the N, the eight output channels,
respectively output, the second channel relative delay the first channel N / 8
time player, and the third channel relative delay the second channel N / 8 time
player, and so on. Each channel broadcast programming cycle, then the first
channel broadcast the next time the channel is also relatively eighth delay N /
8 time player. This adjacent channel broadcast the same program, but the time
interval is N / 8. User demand, its demand information requested by the computer
processing programs, broadcast by the control computer programs will immediately
broadcast to the channel, and other authorized users to receive information
given to the equipment, users N / 8 time, you can see their demand of the
Program.
(2) video-on-demand (VOD)
Video Server can be used not
only quasi-video-on-demand system, can also be used for video-on-demand (VOD)
system. VOD's full name Video On Demand, that is, video-on-demand technology,
also known as interactive television on demand system, that is according to the
needs of streaming video playback. "In the time want to see want to see the
programme", the user can choose according to their wishes to watch TV programs,
a fundamental change in the past passive watching TV the lack of full
realization of the users have access to information from the initiative. VOD can
also achieve Internet, e-mail, home shopping, travel guide, booking
reservations, stock transactions, and other features. Therefore it can be said
that the emergence of this technology allows users to the need to arrange their
work and entertainment, real grasp of the ratings initiative by the user,
greatly enhancing and improving people's quality of life and work efficiency.
VOD system by front-end systems, network systems and customer system
consists of three parts, and the front end by the video server system in
general, all kinds of file servers and management control of part of the network
equipment components. Various file servers to complete some of the major users
of information management and billing, and video materials and the management of
security and confidentiality, and so on. Control of some of the major networks
to complete all the various servers in the transmission of information and
background work of the film materials and data exchange. Video server and
storage systems from the main building its controller on the various management
systems, whose goal is to achieve compression of data storage media, and
according to media requests for information retrieval and transmission. Video
servers and traditional data server in many areas have significantly different,
the need to address many issues, to support all kinds of new features. At the
same time, its high-speed data transmission capacity of the large number of
users guarantee that the film, video, games, business information and other
services almost instant access. It is the biggest characteristic of people from
different starting point for achieving watch the same programme, thus avoiding
the events were a user exclusive.
Application of this relatively large
scale, must be more than one multi-channel video server components can share
large-capacity hard disk storage of transport stream and to be able to deal with
the broadband network in order to meet the many users of the various programmes
on demand needs. User-demand information can be passed on-demand there are two
paths admissibility server: One is through the city's cable TV HFC network
passed on-demand channel uplink admissibility server; another through common
browser on the Internet to choose the program, Will be accepted on demand-demand
information to the server. Will be handled on-demand server information
processing, the broadcast transmission control computer, which will broadcast
user-demand control of the program and spread through the HFC downlink channel
user terminals. Users receive two forms: One is the ordinary TV + set-top boxes,
and the other is the computer + receive cards, the use of computer monitors to
watch.
Based on the multi-channel video server digital broadcast system
is based on the traditional analog broadcast the tape recorder system
unparalleled many advantages, video servers use open software and hardware
platforms and standards or universal interface protocol, the system expansion
stronger ability to And the future all-digital, disk-based, network-based,
multi-channel mode of resource sharing programme production, editing and
broadcast system of convergence. Pandai-based or combination of server-based
multi-channel digital video broadcast system can be broadcast error isolation
and fault isolation, can also achieve delayed broadcast, television broadcast
the transition from analog to digital the best solution. And in the long run,
video-on-demand has enormous potential market and prospects for the development
of far-reaching, because Congshencengci of view, VOD is not just the problem of
video on demand, it represents the future full-featured network and the
application of digital interactive information Development trends, is a content,
more Shencengcishang form of interaction, but also digital cinema, interactive
video news, advertising and new applications of the foundation, has broad
potential for development, VOD is the framework for the future information
superhighway, an important component Part of the future information services in
the broadband business of the soul. So sure, with digital technology, multimedia
technology and computer technology continues to develop, in a television video
server in the field of application there will be more extended.
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