Download - IDRS 即時互動式網際網路數位電台解決方案
主要問題
利用點播 ( unicast) 技術:頻寬需求和上線使用人數成正比
單向點播:聽眾 Call-in 時,仍必須用電話機 單一網路服務品質及媒體展現品質:
網路擁擠和順暢時,都放送相同的資料量到使用者端,完全沒有服務品質( QOS )可言
我們的解決方案:
利用群播( multicast) 技術 : 節省大量頻寬,因使用人數和頻寬要求無絕對關係
雙向互動傳播:聽眾 Call-in 時,直接用電腦和網路,即相當於結合 Real Player / Media
Player 和 I-phone 為一體的軟體系統
我們的解決方案:
使用者端俱有自控服務品質的功能:把 Video 資料分層( layer) ,使用者端在網路順暢時,收播多一些 video layers ,網路擁擠時,收播少一些 video layers 。而系統會依使用者的要求,自動做好影音同步
提供點播和群播 Gateway (AGW): 處在未提供群播( multicast) 功能 ISP 上的使用者,仍能利用點播(unicast) 方式,收播到群播網路上的節目
群播技術與 MBone– Multicast ( 群播 )
Multicasting sends a single copy of the data to those clients who request it. Multiple copies of data are not sent across the network, nor is data sent to clients who do not want it.
– MBone Multicast BackboneThe MBone is a virtual network consisting of those portions of the Internet, sometimes called multicast islands, on which multicasting has been enabled.
簡介 ( 續 )
Multicasts that must travel across areas of the Internet that are not yet multicast-enabled are sent as unicasts until they reach the next multicast enabled island.
多媒體群播應用軟體的設計考量– 即時通訊技術層面
Packet Loss & Jitter Intra, Inter-stream synchronization
– 管理層面 目前網路環境中只有部分 router 連上 MBone. Scalability : Unicast Gateway Multicast 轉換閘道伺服器必須
– 對使用者透明化– 方便管理
全方位即時通訊系統整合方案 :– IDRS (Interactive Digital Radio Station)– IMS (Interactive Music Station)– IAVS (Interactive Audio & Video Station)– QMAV (QoS-based Multicast Audio and Video System)
What can they do?– Internet-based radio,music, and TV systems.– Provide a multimedia multicast environment.– Include media streaming & multiple-stream synchronization
Techniques.– Two-way communication in the 1-to-n networking environment:
an audience or a spectator can have Call-Ins using a computer.
IDRS 系統執行架構
MRouter
Modem
PSTN
Audience(Home PC)
Audience(Home PC)
Internet
MRouter
Audience(Net PC)
Audience(Net PC)
MRouter
AGW
TCP/IP-based Network
Audience(Net PC)
Audience(Net PC)
(Net PC)Audience
(Net PC)Audience
(Net PC)Audience
DJ Server(Net PC)Audience
(Net PC)Audience
AGW
ModemModem
IDRS 系統執行架構 ( 續 )
兩種連線模式– audience PCs are attached directly to the same LAN
in which the mrouter is located– audience PCs are not attached to the LANs that are
associated with MBONE
Audience GateWay
mroutd
Sun Sparc 20Multicast Interface Unicast Interface
AGWMrouter
Internet
Audience
Audience
Audience
(b)
QoS 視訊傳輸機制
視訊媒體的壓縮格式特性I P DP D D DP P P P P P P P
D Frame 向前參考 I 或 D Frame
P Frame 向前參考 I,D 或 P Frame
I Frame 不需參考
IAVS 之 QoS 機制
使用者可根據自己的網路環境 , 動態選擇要接收的 Media Layer
IAVS Server
Internet
Live Audio
Live AudioMP3
Base LayerEnhance Layer1Enhance Layer2
Live Audio
MP3
Base Layer
EnhanceLayer1
EnhanceLayer2
Live AudioMP3
Base Layer
Client 連接 T1 網路Client 連接 ADSL
Client 連接 Modem
IAVS QoS 機制特性
– 從 Modem 使用者到高速網路使用者都可接收節目
– 提供多種媒體 , 多重品質的節目內容
– 收訊途中使用者可隨時切換接收的媒體層級 , 以因應網際網路環境的變化特性
管理層面 –閘道指位器
要解決的問題 : Which one of existing AGWs is suitable for me? How to manage these AGWs? Is there an easy way for clients to get connecting without
maintaining an AGW address list locally?
閘道指位器 ( 續 )
AGW
• Heterogeneous communication model of our approach
Clients using unicastClients using multicast
閘道指位器 ( 續 )
Heterogeneous Environment
Station Locater
Client Client ClientQuery process
AGW AGW AGW
………
………
閘道指位器 ( 續 )
System Locater Architecture and Operation scheme
Address Indexer
Web ServerDatabase
Client Brower + IDRS(IMS, IAVS)
ActiveX Clone
AGW
1
3
2
4
Java daemon maintainActive AGW List
Alive Packets
Station Locater
The Browser has a connection
to the web server
The Browser has a connection
to the web server
The web server executes address indexer. The indexer searches the active AGW list to get an appropriate address according to the address of request client.
The web server executes address indexer. The indexer searches the active AGW list to get an appropriate address according to the address of request client.
The web server returns the AGW’s IP address to client’s ActiveX system.
The web server returns the AGW’s IP address to client’s ActiveX system.
The Client connects with the specific AGW and starts to receive the program.
The Client connects with the specific AGW and starts to receive the program.
結論 本實驗室發展出一系列即時互動式群播通訊解決
方案 , 是能切合目前網路環境並提供有效率溝通的應用軟體
IDRS, IMS, IAVS, and QMAV 中的各項子系統或元件可應用在網際網路中提供多媒體娛樂資訊 .
彈性化的媒體流轉換閘以及閘道指位器所形成的通訊架構能夠大幅擴張應用領域及群播軟體的應用範圍