1.System Architecture Diagram
2.Content Delivery Network (CDN)
Content delivery network (CDN) consists of central nodes and prefectural or border nodes. The architecture of nodes is as presented in the following figure:
It is recommended that a provincial-level network company establishes a central node and arranges several border nodes at the prefectural/municipal level to realize content caching and service and provide the services for broadcasting users throughout the province. First, a complete channel library is established at the central node to gather the data of programs on all channels. The prefectural/municipal-level nodes can select the corresponding channels according to actual needs, and provide different quantities of servers based on different quantities of users at different prefectural and municipal levels.
3.Live Broadcasting Management
Inspur’s live broadcasting system optimizes the acceleration of video contents unique. With regard to live broadcasting, time shift and playback, the unified conversion shard is employed at the source to quickly distribute in fixed unit on the CDN network. With regard to streaming, specific streaming server module is provided to realize the minimum delay and highly concurrent broadcasting, and offer the continuous time shift within one hour. It can feed into CDN synchronously as the support for 7-day EPG time shift/playback.
The live broadcasting playback module of Inspur’s OTT platform has the following advantages:
Low latency of broadcast
Broadcast stream employs small shard to guarantee flow rate and low latency. It is recommended to download the broadcasting contents via multicast, and accept by the streaming server at node, at least cache server, which can also reduce latency;
High concurrency of server
Each standard server supports up to 6G bandwidth of user clicks;
Continuous watch of time shift program
The limit of EPG is eliminated to prevent the errors of EPG from causing incomplete or inaccurate recording of program;
Seamless fail-over of servers and nodes
The real-time SRM technology is utilized to guarantee the fail-over of servers and nodes and protect users against single point of failure;
Supporting source files in multiple formats
Data sources for live broadcasting in multiple formats are supported, including TS and MP4, which are converted into the unified TS format through cloud conversion platform and used for the HLS shard packaging; (refer to the input parameters of cloud conversion platform for supported parameters)
Supporting multiple coding formats
live broadcasting sources in multiple formats are supported, including MPEG2 and H.264, which are converted into the efficient H.264 format through cloud conversion platform; (refer to the input parameters of cloud conversion platform for supported parameters)
Media can be converted into the designated format, but HLS protocol is recommended considering the live broadcasting function of mobile terminals, e.g. mobile phone.
Advantages of HLS protocol
HLS protocol is employed to support iOS and PC. For the native support of mobile terminals, it has low power consumption and functions steadily;
APP client and Web access are both supported (Web access provides the contents of low code rate and the security of openness);
Multi-resolution/code rate. It is adaptive to terminals and network bandwidth.
4.Time Shift Management
In the distribution architecture of program playback, time shift server caches the video streaming contents from live broadcasting source, and then distributes the contents with the two-level architecture for processing VOD business.
The feature of time shift is achieved through the collaboration of several modules, i.e. live broadcasting, recording, storage, transmission and terminal display. The working principles of these modules are as follows:
Live broadcasting gathering module
live broadcasting gathering module is responsible for receiving the live broadcasting streams from the video gathering and compression equipment, and repackaging and feeding them into CDN network.
Recording module
Recording module can record and save the videos at the designated interval, and generate the independent files of any time interval and size with the help of customized output.
Storage module
Time shift module uses distributed storage at the fixed size (time length) and fixed format without relying on specific index server, and couples with EPG containing standard timestamp.
Transmission module
Transmission module can push the live broadcasting programs to each streaming server based on Inspur’s CDN system, so as to ensure the normal streaming service and live broadcasting service for users.
Terminal display
With regard to PC, smart phone, PAD and other equipment, Inspur utilizes self-developed player for program index and broadcasting, so users can locate their favorite programs quickly.
Time shift player supports the playback of program half an hour ago during live broadcasting, and realizes the random drag for broadcasting within half an hour of time shift. It can support the uninterrupted video streaming time shift storage and VOD within 72 hours.
Time shift player offers two positioning mechanisms, i.e. time scale positioning and EPG positioning. Time scale positioning supports the rapid positioning of 1h (recommended) time scale within the date of time shift. EPG positioning supports capturing the contents within the time period set on EPG from the stored contents for 7 days (recommended), so as to realize the independent storage VOD feature. During time shift, the pictures appear in succession without frame skip, while minimum positioning accuracy is less than 5s. It supports the common operations including pause/resume/fast forward/fast backward/maximize, etc. It provides friendly and compact interface.
5.Back Office (BO)
BO provides the full domain management, data support, resource scheduling, authentication billing services to the system, integrately realizing functions of multiple modules, such medata management, sessions resource management, business authorization and billing modules. As the core, BO integrates business of CMS, billing system, sessions resource system, portal and set-top box, among which optimization decisions should be made according to the full domain VOD situation and the current distribution situation for the distributed scheduling of video programs in CDN system to maximize local services of VOD affairs. In addition, unified distribution is required to allocate service resources and loads for VOD requests, so as to better manage system resources. Therefore, BO should adopt the centralized deployment pattern to realize efficient management.
6.Content Management System (CMS)
The content management system adopts unified storage on the storage technique building bottom, and allocates different work spaces in memory to complete the content transfer from introduction, editing to output.
The content management system realizes the unified management over the content of VOD programs, realizing functions of media content processing, resource management, uploading, review, program going on-line and off-line and program recommendation management.
The architecture for video management module is as as follows:
7.Portal
The portal is designed with the dynamic Web standard HTML5 language development and the multi-screen support such as the set-top box, mobile phone and tablet. The media portal supports the full dynamic modification. Through the CMS management configuration function, functions of homepage recommendation, column change and program adjustment can be achieved.
Main display functions of the current media portals include: Homepage, program list, play history, program scoring, breakpoints during play, user collection and play ranking.
8.Empowerment System (ES)
The empowerment system is mainly used for business opening, product ordering, authentication management and billing synchronization functions, as well as docking with the BILLING (BOSS) system to achieve synchronization of user’s ordering and unsubscribing. It can realize the VOD/SVOD-based billing mode.
This file provides the following docking method: Inspur offers the billing API, and the BILLING system is required to provide docking with the platform. The billing process is as follows:
The actual business docking requires the joint communication between the BILLING system and the VOD system and it can be realized on the basis of actual docking interfaces.
9.Video Streaming Server (VSS)
The streaming service provides users with VOD program streams and it adopts the world’s most widely used internet TV transmission technology protocol, and data are transmitted through the HTTP (HLS) protocol, breaking away from the isolation of firewalls or agents, so as to achieve fast download of program streams and improve utilization of high bandwidth. When the terminal users request a specific media content (VOD or live broadcasting) on the VSS, the streaming media server uses the data stream technology to send media materials to the user’s terminal.
When the terminal user requires to broadcast the media content on demand, the user’s terminal first executes the program browsing and index through Portal, the load balancing system schedules to the VSS most suitable for users’ providing services after passing the authentication of authentication server for users’ requesting programs, and the media server will provide the streaming media to users.
After receiving the user’s request, the VSS will search the media content required by the user from native media library according to attributes of the user’s request, and send such media content in a stream way after file format analysis. During this period, the media server maintains a sessions with the management user, and deals with various requests of pause, play, forward and backward during play on the terminal.
10. Multi-screen
Smart phone has become a part of everyday life. It is our new task to study how to realize the interaction between smart phone and smart STB, to make the smart phone an entrance for users to watch TV programs.
With the mobile app by Inspur, the user may watch the same channels on the phone as the TV, share the programs on social networks, share local programs, use the phone as RCU and multi-screen share among phone, pad and STB.
Main functions:
Live TV program previewLive TV on smart phone. Smart phone RCUProgram appointment and reminderPush recommended programsVoice controlRecommendationsMulti-screen share
11.Transcoding
Inspur cooperates with 3-rd party partners, who will provide the proposal and specifications, to realize the transcoding functions. Therefore in this document we do not do further explanation.
