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H.323 網路電話視訊監控與錄製系統之研製 The design and Implementation of video monitoring and recording system for H.323-based internet phone. Adviser: Ho-Ting Wu Speaker: Chih-Hao Tseng Institute of Computer Science and Information Engineering National Taipei University of Technology. Outline. Introduction
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H.323網路電話視訊監控與錄製系統之研製The design and Implementation of video monitoring and recording system for H.323-based internet phone Adviser: Ho-Ting Wu Speaker: Chih-Hao Tseng Institute of Computer Science and Information Engineering National Taipei University of Technology
Outline • Introduction • Netmeeting • Related Protocol • H323vRec_EXE • Conclusion • Reference
Introduction • Packet Capture(winpcap) • H.323 V2oIP analysis • RTP Protocol decode • Why develop H323vRec_EXE
NetMeeting Destination IP orname 連線按鈕 中斷連線鈕 Destination 使用者畫面 網路目錄 Source 使用者畫面 影像播放控制鈕 音量調節鈕 使用者影像顯示鈕 已連線之遠端使用者姓名
Related protocol • H323 • Q.931, H.225, H.245 • RTP • G.723.1 • H.263
RAS Channel 1. ARQ (alias address/bandwidth) 2. ACF (call signaling channel address/bandwidth) 6. ACF Q.931 Call Signaling Channel 5. ARQ 3. Setup 4. Call Proceeding 7. Alerting 8. Connect (H.245 Address) H.245 Control Channel (Logical Channel 0) Master/Slave Determination Capability Exchange OpenLogicChannel (RTCP address) OpenLogicChannelACK (RTP & RTCP address) RTP Stream RTCP Stream RTCP Stream H.323 Call Setup Flow Chart Gatekeeper Terminal Terminal endSessionCommand
Q.931 • In Original, for Circuit Switched Network(CSN) • Direct Endpoint Call signaling • Two part • TPKT • TPDU
TPKT • Version: 1 Byte • Reserved: 1 Byte • Length: 2 Byte • Length of Q.931 & H.225 control signal message
TPDU • f: Call reference flag • E: extension indicator • CS: coding standard • ITC: information transfer capability • TM: transfer mode • ITR: information transfer rate
H.225 • Setup • Call Proceeding & Alerting • Connect • Release
H.225 setup • MessageBody • Protocol identifier • ITU-T recommendation h225 version 4 • Source Address • H323ID • Country code • destCallsignalAddress • IPaddress • Port • ConferenceGoal & Call Type • Create • p2p • SourceCallSignalAddress • Ipaddress • port
H.225 Alerting • H323-Message-Type • Alerting • protocolIdentifier • distinationInfo • CallIdentifier
H225 connect • MessageBody • Protocol identifier • ITU-T recommendation h225 version 4 • h245Address • IPaddress • Port • Destinationinfo • contrycode • ProdectID
H.225 Release • MessageBody • ProtocolIdentifier • Reason • CallIdentifier
H.245 • Master-Slave determination • Capability Exchange • Opening and Closing of Logical Channel
Terminal Capability Set • Protocol Identifier • MultiplexCapability • H225capability • Receive Multipoint Capability • Transmit Multipoint Capability • Receive & transmit Multipoint Capability • CapabilityTable • Receive & transmit data capability • Receive audio capability • Receive video capability • MasterSlaveDetermination
Open Logical Channel • Forward logical channel number • Forward logical channel parameter • Data type • Video capability • Multiplexparameter • Logical paramter • Ipaddress • port
Open Logical Channel ACK • ForwardMultiplexAckParameter • SessionID • mediaChannel • IPAddress • IP • port • MediaContorlChannel • IPAddress • IP • port For RTP packet For RTCP packet
EndSessionCommand • PDUType • Command • EndSessionCommand • Disconnect - NULL
G.723.1 • An ITU-T standard codec that uses • 6.4 kbit/s (using 24 byte frames) using a Multipulse LPC with Maximum Likelihood Quantization (MPC-MLQ) algorithm • 5.3 kbit/s (using 20 byte frames) using an Algebraic Code Excited Linear Prediction (ACELP) algorithm
H.263 • Extension of ITU-T H.261 • H.263 is an ITU standard, designed for low bitrate communications • The encoder decoder accepts UYVY, YUV2, YV12, I420, RGB24 and RGB32 formats.
I, P, B frame • Intra coded Pictures • Predictive coded pictures • Bi-directionally coded pictures
H.263 Header H.263 Payload Header
H323vRec_EXE • Done • H323 packet analysis • Video, audio packet capture • H.263 Video decoder • Future work • G.723.1 Audio decoder • Video, audio combination • Synchrolization
Conclusion & Future Work • Hard to be a tertium quid • Addition of codec • Extend VoIP protocol
Reference • OpenH323, “http://www.voxgratia.org/” • OpenH323, “http://www.openh323.org/” • 孫行得, “An experimental study of VoIP Architecture”, 電腦通訊工程系, 高雄第一科技大學, 95年7月 • 朱明輝, “Development of Internet Video Conference System”, 通訊工程研究所, 中央大學, 92年7月 • 紀鈞閎, “動態影像在紅外線中傳輸與錯誤消除技術之研究” , 電機工程研究所, 中央大學, 92年7月 • http://www.geocities.com/hot_bid_168/netmeeting/netmeeting.html,如何設定netmeeting,微軟網站 • http://en.wikipedia.org/wiki/H323 • http://www.h263l.com/ • http://www.answers.com/topic/g-723-1?cat=technology