DMB 서비스 기술 임 영 권

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

Backward Compatibility

DMB 서비스 구조

DMB 송신 개념도

High level architecture

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

Packet Structure 김용한, “ 지상파 DMB 표준 ”, 한국방송공학회 디지털방송기술워크샵,

Efficient Use of Bandwidth

FEC Target BER = Two well-known methods convolutional interleaving reed-solomon coding

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

TS packet headers

PES packet headers

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

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

ObjectTypeIndication 0x02Systems ISO/IEC x21Visual ISO/IEC x40Audio ISO/IEC x6CVisual ISO/IEC (JPEG) 0xC0 – 0xFEuser private

streamType 0x01ObjectDescriptorStream 0x02ClockReferenceStream 0x03SceneDescriptionStream 0x04VisualStream 0x05AudioStream 0x20 - 0x3Fuser private

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

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

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

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

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

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

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. FormatPicWidthInMbsPicHeightInMbsPicSizeInMbs QCIF11990 QVGA WDF CIF Video Level

Audio ISO/IEC ER BASC Audio Object (0x22) Restrictions AudioSpecificConfig() epConfig : 0 frameLengthFlag : 0 dependsOnCoreCoder : 0 bsac_header() SBA_mode : 0 general_header() ltp_data_present : 0

Audio 항목내용 Sampling freq.(Hz)24000, 44100, Number of channel1, 2 Number of objects1 Maximum bit rate128 kbps (stereo)

Convergence

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

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

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)

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

Acknowledgement to All of M 2 B members