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DMB 서비스 기술

DMB 서비스 기술. 임 영 권 young@netntv.co.kr. Characteristics of T-DMB. Backward Compatibility Efficient use of bandwidth Convergence between broadcasting & communication. Backward Compatibility. DMB 서비스 구조. DMB 송신 개념도. Display and User Interaction. Interactive Audiovisual Scene.

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DMB 서비스 기술

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  1. DMB 서비스 기술 임 영 권 young@netntv.co.kr

  2. Characteristics of T-DMB • Backward Compatibility • Efficient use of bandwidth • Convergence between broadcasting & communication

  3. Backward Compatibility

  4. DMB 서비스 구조

  5. DMB 송신 개념도

  6. Display and User Interaction Interactive Audiovisual Scene Composition and Rendering AV ObjectsData Compression Layer Upstream Information ... Elementary Streams Scene Description Information Sync Layer SL SL SL SL SL SL SL-Packetized Streams Delivery Layer Object Descriptor (PES) MPEG-2 TS Eureka 147 DAB channel High level architecture

  7. DMB components MPEG-4 AVC Video MPEG-4 BIFS Interactive Contents MPEG-4 BSAC Audio MPEG-4 SL Encapsulation MPEG-4 SL Encapsulation MPEG-4 SL Encapsulation MPEG-2 TS Multiplexing Forward Error Correction EU-147 Stream Mode

  8. Packet Structure 김용한, “지상파DMB표준”, 한국방송공학회 디지털방송기술워크샵, 2004.10.12

  9. Efficient Use of Bandwidth

  10. FEC • Target BER = 10-8 • Two well-known methods • convolutional interleaving • reed-solomon coding

  11. MPEG-2 TS • Stream Multiplexing • Program association table • Program map table • PID, stream_id • Random Access • Fixed size TS packets with sync. byte • Start codes • Framing • variable size PES (Packetized elementary stream) packet • fixed sized TS packet

  12. TS packet headers

  13. PES packet headers

  14. MPEG-4 Systems • SL for Synchronization • CTS (Composition Time Stamps) • DTS (Decoding Time Stamps) • BIFS for Interactive composite multimedia • OD Framework • Scene Description • Only one audio • Only one video

  15. MPEG-4 descriptors • shall use • ObjectDescriptor • InitialObjectDescriptor • ESDescriptor • DecoderConfigDescriptor • SLConfigDescriptor • shall not use • IPMPDesrciptor • IPMPDescriptorPointer • IPIDescriptorPointer

  16. ObjectTypeIndication

  17. streamType

  18. SL packet encapsulation • useAccessUnitStartFlag • useAccessUnitEndFlag • useRandomAccessPointFlag = 0 • hasRandomAccessUnitsOnlyFlag= 0 • usePaddingFlag = 0 • useIdleFlag = 1 • useTimeStampsFlag = 1 • durationFlag • timeScale • accessUnitDuration • compositionUnitDuration

  19. SL packet encapsulation • timeStampResolution : 90kHz • OCRResolution : 90kHz • timeStampLength : ≤ 33 bits • OCRLength : ≤ 33bits • AU_Length = 0 • instantBitrateLength • degradationPriorityLength = 0 • AU_seqNumLength = 0 • packetSeqNumLength = 0

  20. 4on2 • Timing relationship • MPEG-4 OTB is locked to the MPEG-2 STC • PTS shall be present if and only if OCR is carried. • SL-packetized streams in PES packets • Stream_id = 0xFA • A single SL-packetized stream may be mapped into a single PES • One and only one SL packet shall consist the payload of PES packet

  21. Random Access • PAT • single program per TS • period ≤ 500 msec. • PMT • IOD_descriptor in the first loop • SL_descriptor in the second loop • period ≤ 500 msec. • PCR period ≤ 100 msec • OCR period ≤ 700 msec • CTS period ≤ 700 msec

  22. 4on2 Content Access Procedure 6. Locate SceneDescriptionStream 7. Locate OD Stream 1. acquire PMT 2. identify IOD 8. Locate media streams 3. identify ESD 4. identify SLCD 5. generate PID v.s. ESID map table

  23. Video Profile • Baseline profile • No Arbitrary slice order • PPS(Picture Parameter Sets) • num_slice_groups_minus1 = 0 • redundant_pic_cnt_present_flag = 0 • SPS(Sequence Parameter Sets) • pic_order_cnt_type = 2 • num_ref_frames = 3

  24. Video Level • Level 1.3 • Picture Format • Vertical MV component range (MaxVmvR) : [-64,+63.75] • Maximum Frame Rate : 30fps • MaxDPB : 445.5kbytes • IDR picture period ≤ 500 msec.

  25. Audio • ISO/IEC 14496-3 ER BASC Audio Object (0x22) • Restrictions • AudioSpecificConfig() • epConfig : 0 • frameLengthFlag : 0 • dependsOnCoreCoder : 0 • bsac_header() • SBA_mode : 0 • general_header() • ltp_data_present : 0

  26. Audio

  27. Convergence

  28. Concept DMB 무선인터넷 VoD AoD 쇼핑 벨소리 연결음 …. MPEG-4BIFS

  29. MPEG-4 Systems Core2D profile • Video on Demand • interactive audio-video over the Internet • scalable content delivery • Enhanced digital TV • MPEG-4 video over MPEG-2 Picture in Picture • Interactive Electronic Program Guides • enriched TV programs • Advertisement • animated banners • video warping and incrustation • Personalization • web links • Interactive presentations • basic graphics animations • e-commerce • interactive contests or voting

  30. Core2D Scene Description Profile • basic 2D composition • 2D texturing • local interaction • local animation • BIFS updates • quantization • access to web links and sub-scenes • back channel (ServerCommand) • VoD features (MediaControl, MediaSensor)

  31. Conclusion • EU-147 Stream Mode • FEC : RS + Convolutional Interleaving • Transport : MPEG-2 TS • Adaptation : MPEG-4 SL • Video : MPEG-4 AVC Baseline Profile • Audio : MPEG-4 BSAC • Graphics & Data : MPEG-4 System Core2D Profile

  32. AcknowledgementtoAll of M2B members

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