DVBPROJECTI 2 DVB Digital Video BroadcastingDVB Project DVB
DVB-PROJECT-(I) 2 �DVB, Digital Video Broadcasting,是由「DVB Project」維護的一系列為國際所承認的數位電視公開 標準。「DVB Project」是一個由 300多個成員組成的 業組織,它是由歐洲電信標準化組織(European Telecommunications Standards Institute, ETSI)、 歐洲電子標準化組織(European Committee for Electro technical Standardization, CENELEC)和歐 洲廣播聯盟(European Broadcasting Union, EBU) 聯合組成的「聯合專家組」(Joint Technical Committee, JTC)發起的。幾項DVB子標準的關係在 《DVB指南》(DVB-Cook)中描述之。
DVB-HISTORY 3
Mobile TV 系統狀況 4 Region Fixe Standard Portable/Mobile Standard Europe DVB-T DVB-H Korea ATSC T-DMB Japan ISDB-T ISCB-T(1 -seg) North America ATSC DVB-H/Media. FLO China DMB-TH/CMMB India DVB-T T-DMB Taiwan DVB-T DVB-H
DVB/T 5
What is DVB-H? -(II) 8
What is DVB-H? -(III) 9
New features in DVB-H 10 �OFDM 4 K mode �In-depth interleaving Inner interleaver exchange data in 8 k range �Additional info in TPS(Transmission Parameter Signaling) to singal 4 k mode Time-slicing MPE-FEC
DVB-H PSI/SI Information 11 PSI (Program Specific Information): 節目特定資訊, defined in MPEG-2 SI (Service Information): 服務資訊, defined in DVB 縮寫 全名 PID table_id PAT Program Association Table 0 x 0000 0 x 00 PMT Program Map Table * 0 x 02 NIT Network Information Table 0 x 0010 0 x 40 INT IP/MAC Notification Table * 0 x 4 C SDT Service Description Table 0 x 0011 0 x 42
DVB-H的ID 13 id 存在/定義 用途 MPEG-2 TS packet header MPEG-2 TS packet的識別碼 network_id 由NIT定義 網路編號(network provider 的識別碼) transport_stream_id 由PAT定義 TS的識別碼 (一個network provider可能會提供好幾條TS) platform_id 由INT定義 IP/MAC platform 的識別碼 由NIT(PMT)定義 節目(即服務) 的識別碼 = program number in PMT。 first byte of a section的識別碼 PID service_id table_id
DVB networks 14
Time Slicing-(I) 17 DVB-H DVB-T DVB-H Time Slices Regular DVB-T Multiplex(TV) Sleep Mode Always ON – 沒用到的DATA則忽略掉 data
DVB-H Bootstrap 19
DVB-H IPDC Protocol 20
RTP 21 �RTP(real-time transport protocol) �用來攜帶具有即時特性的資料 �包含Sequence number 和 timestamp �不保證Qo. S �Router不能辨識RTP
RTP Format 22 (Ver)Version : 0 x 2 (P)Padding: In use = 1 ; otherwise = 0 (X)Extension: In use = 1; otherwise = 0; (CC)CSRC count: # of CSRC (M)Marker: Frame boundary (PT)Payload type: GSM, LPC, MPEG audio, H. 264, etc Sequence Number: 每送一個RTP封包則加一 Timestamp: Time instance of First byte in RTP packet Synchronization source identifier (SSRC): Identify source of RTP stream; Each stream in RTP session has distinct SSRC is randomly assigned CSRC: Source identifier
RTCP 24 �RTCP(RTP control protocol) in DVB-H 用來監控服務的品質,並傳達會議中的參與者的資料 在DVB-H中 RTCP是用來做Lip Sync 提供Audio 和 Video 對應的Wall clock 和time stamps 只需要考慮到Sender report RTCP Port number = RTP Port number +1
FLUTE Basic 26 File Delivery over Unidirectional Transport (FLUTE) protocol RFC 3926 [1] 單向檔案傳輸 檔案被當成一個物件再傳送,也許內容可以會經過一些編碼(e. g. gzip) Distribution to large number of receivers可以發送給大量的接收者 接收端不用回傳,所以接收端可以說是沒有限制的,不管是幾萬個還是幾百萬個都沒有問題 支援IPv 4 和 IPv 6 在Flute的Header並沒有特別關於IP version的部分 在Multicast 和 unicast下的UDP傳輸都適用 特別是適用於multicast networks Supports Any Source Multicast(ASM) and Source Specific Multicast(SSM) models 透過Retransmissions和Forward Error Correction機制來保證其可靠度
FLUTE session 參數 30 �FLUTE標準(RFC 3926)中,只提出了FLUTE session 傳輸參數應包含的種類 FLUTE session傳送端的IP位址 FLUTE session的TSI FLUTE session所包含的FLUTE channel數 每個FLUTE channel的目的IP位址與Port number FLUTE session的開始與結束時間 FLUTE session或FLUTE channel預設的FEC演算法 但是在RFC 3926中並無明確定義用什麼方式去記錄這些 參數,所以在DVB-IPDC CDP標準中,定義了基於 SDP(Session Description Protocol)
SDP(Session Description Protocol) Type Description v protocol version o originator and session identifier s session name i session information c Example 31 connection information c=<nettype><addrtype> <connectionaddress> v=0 o=1221269…, IN IP 4 192. 168. 16. 23 s=Eins. Extra i=Live TV-Stream Eins. Extra c=IN IP 4 228. 1. 3/3 Internet IPv 4 destination IP/time to live/(number of addresses) m media name and transport address m=<media> <port> <transport protocol> <format>. . . format 96 -127 is defined dynamically. Therefore, attribute fields must be parsed m=video 6000 RTP/AVP 96 m=audio 6002 RTP/AVP 97 6000, 6002代表port numbers RTP/AVP: RTP Audio/Video Profile 96, 97代表RTP payload types a attributes a=<attribute>: <value> a=rtpmap (rtp payload type map) a=fmtp (format parameter) a=sourcefilter(IP address) a=flute-tsi(TSI of this session) a=FEC-delclaration (FEC format) a=content-desc(傳送目的位址) a=rtpmap: 96 H 264/90000 format (rtpmap) 96: H. 264 with clock rate 90 k. Hz. a=fmtp: 96 packetization-mode=1; profile_level_id=42 e 00 c; … more descriptions about format 96
SDP Example 32
FDT instance Example 33 一個FDT-Instance可以描述全部或是部分這個FLUTE session
FLUTE Header 34 V: 為ALC與LCT的版本號碼,目前版本(RFC 3450) 的值為 1。 C(CC flag)與CCI: C的值決定CCI的長度 , C=0則CCI 32 bit ; C= 1, CCI = 64 bit…但是DVB-H不做CC所以用不到,但是根據 DVB-IPDC CDP規定CCI = 32 bit , C = 0; R(reserved): 值為 0 S(TSI flag): TSI length = 32 * S + 16 *H O: TOI length = 32*O+16*H H: Half word(0 b 0 in DVB-H) T與SCT: T 為Sender Current Time present flag(0 b 0), 決定 SCT是某存在,SCT為SESSION開始之後經過的時間單位為 1 ms R與ERT: R為Expected Residual Time Present flag(0 b 0), 決 定ERT是某否存在,ERT用來表示TOI所選的ALC OBJECT 會被繼續傳多久 A: Closing session flag B: Closing object flag HDR_LEN: Header length(unit 32 bits)包含原本的 HEADER和擴充的HEADER長度 LCT Header 只有在TOI = 0的時候會顯示 Codepoint(CP) : 記錄ALC所採用的FEC演算的ENCODING ID
Reference 35 � � � � � ETSI EN 302 304: "Digital Video Broadcasting (DVB); Transmission System for Handheld Terminals". ETSI EN 300 744: "Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for digital terrestrial television". IETF RFC 0791: "Internet Protocol". ETSI TR 102 469: "Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Architecture". ETSI EN 300 468: "Digital Video Broadcasting (DVB); Specification for Service Information (SI) in DVB systems". ETSI EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting". ETSI TS 102 468: "Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Set of Specifications for Phase 1". ETSI TS 102 472: "Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Content Delivery Protocols". ETSI TS 102 470: "Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Program Specific Information PSI)/Service Information (SI)". ETSI TS 102 474: "Digital Video Broadcasting (DVB); IP Datacast over DVB-H: Service Purchase and Protection". ETSI TS 102 005: "Digital Video Broadcasting (DVB); Specification for the use of Video and Audio Coding in DVB services delivered directly over IP protocols". IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications". IETF RFC 3926: "FLUTE - File Delivery over Unidirectional Transport". IETF RFC 3452: "Forward Error Correction (FEC) Building Block".
36 THANKS
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