이 문서에서 다루는 내용은 ISO/IEC 13818에서 다루고 있는 Data broadcasting에 대한 주제이며 이것의 연장선에서 봤을때 DVB 및 여러 방송매체에서 다루는 여러 확장사항을 두서없이 열거하는식으로 서술합니다. 개인적인 해석관점에서 작성되었으므로 실제 사양과 불일치하는 부분도 있을수 있습니다. 틀린부분이나 기타 개선이 필요한 부분은 지적해주시면 감사하겠습니다.

Upload new Attachment "dsmcc_layer.png"

    Syntax                       No. of bits
-----------------------------------------------------
service_descriptor_section() {
    table_id                     8 uimsbf
    section_syntax_indicator     1 bslbf
    reserved_future_use          1 bslbf
    reserved                     2 bslbf
    section_length               12 uimsbf
    transport_stream_id          16 uimsbf
    reserved                     2 bslbf
    version_number               5 uimsbf
    current_next_indicator       1 bslbf
    section_number               8 uimsbf
    last_section_number          8 uimsbf
    original_network_id          16
    reserved_future_use          8
    for(i = 0;i < N;i++) {
        service_id               16
        reserved_future_use      6
        EIT_schedule_flag        1
        EIT_present_following_flags 1
        running_status           3
        free_CA_mode             1
        descriptors_loop_length  12
        for(j = 0;j < N;j++) {
            descriptor()
        }
    }
    CRC_32                       32 rpchof
}

    Syntax                       No. of bits
-----------------------------------------------------
event_information_section() {
    table_id                     8 uimsbf
    section_syntax_indicator     1 bslbf
    reserved_future_use          1 bslbf
    reserved                     2 bslbf
    section_length               12 uimsbf
    service_id                   16 uimsbf
    reserved                     2 bslbf
    version_number               5 uimsbf
    current_next_indicator       1 bslbf
    section_number               8 uimsbf
    last_section_number          8 uimsbf
    transport_stream_id          16
    original_network_id          16
    segment_last_section_number  8
    last_table_id                8
    for(i = 0;i < N;i++) {
        event_id                 16
        start_time               40
        duration                 24
        running_status           3
        free_CA_mode             1
        descriptors_loop_length  12
        for(j = 0;j < N;j++) {
            descriptor()
        }
    }
    CRC_32                       32 rpchof

    Syntax                       No. of bits
-----------------------------------------------------
service_descriptor() {
    descriptor_tag               8 /* = 0x48 */
    descriptor_length            8
    service_type                 8 /* = 0x0C : data broadcast */
    service_provider_name_length 8
    for(i = 0;i < service_provider_name_length;i++) {
        text_char                8
    }
    service_name_length          8
    for(i = 0;i < service_name_length;i++) {
        text_char                8
    }
}

    Syntax                       No. of bits
-----------------------------------------------------
data_broadcast_descriptor() {
    descriptor_tag               8 /* = 0x64 */
    descriptor_length            8
    data_broadcast_id            16 /* = 0x0006 : data carousel */
    component_tag                8
    selector_length              8 /* = 0x10 */
    {
        carousel_typ_id          2 /* = 0x02 : two layer carousel */
        reserved                 6 /* = 0x3F */
        transaction_id           32
        time_out_value_DSI       32 /* milliseconds */
        time_out_value_DII       32 /* milliseconds */
        reserved                 2 /* 0x03 */
        leak_rate                22
    }
    ISO_639_language_code        24
    text_length                  8
    for(i = 0;i < text_length;i++) {
        text_char                8
    }
}

• data_broadcast_id

  data_broadcast_id값		설명
  0x0000		reserved for future use
  0x0001		bit pipe
  0x0002		asynchronous data stream
  0x0003		synchronous data stream
  0x0004		synchronized data stream
  0x0005		multiprotocol encapsulation
  0x0006		data carousel
  0x0007		object carousel
  0x0008		DVB ATM streams
  0x0009~0x00EF		reserved for future use by DVB
  	0x000A	system software update service
  0x00F0~0x00FF		reserved for DVB MHP
  0x0100~0xFFFE		reserved for registration
  0xFFFF		reserved for future use

• carousel_typ_id

  carousel_typ_id값	설명
  0x01	one layer carousel
  0x02	two layer carousel

    Syntax                       No. of bits
-----------------------------------------------------
compatibilityDescriptor() {
    compatibilityDescriptorLength 16
    descriptorCount              16
    for(i = 0;i < descriptorCount;i++) {
        descriptorType           8
        descriptorLength         8
        specifierType            8 /* = 0x01 : IEEE OUI */
        specifierData            24
        model                    16
        version                  16
        subDescriptorCount       8
        for(j = 0;j < subDescriptorCount;j++) {
            subDescriptor()
        }
    }
}

subDescriptor() {
    subDescriptorType            8
    subDescriptorLength          8
    for(k = 0;k < subDescriptorLength;k++) {
        additionalInformation    8
    }
}

downloadControlMessage() {
    dsmccMessageHeader()
    controlMessagePayload()
}

downloadDataMessage() {
    dsmccDownloadDataHeader()
    dataMessagePayload()
}

    Syntax                       No. of bits
-----------------------------------------------------
dsmccMessageHeader() {
    protocolDiscriminator        8 /* = 0x11 */
    dsmccType                    8 /* = 0x03 */
    messageId                    16
    transactionId                32
    reserved                     8 /* = 0xFF */
    adaptationLength             8
    messageLength                16
    if(adaptationLength > 0) {
        dsmccAdaptationHeader()
    }
}

• protocolDiscriminator: 이 값은 항상 0x11 입니다.
• dsmccType

  dsmccType 값	설명
  0x00	ISO/IEC 13818-6 예약
  0x01	User-to-Network configuration message
  0x02	User-to-Network session message
  0x03	Download message
  0x04	SDB Channel Change Protocol message
  0x05	User-to-Network pass-thru message
  0x06~0x7F	ISO/IEC 13818-6 예약
  0x80~0xFF	사용자 정의 message

• transactionId
  • bits 0~29 : Transaction Number
  • bits 20~31 : Transaction Id Originator

    originator 값	설명
    0x00	transactionId는 Client에 의해서 할당
    0x01	transactionId는 Server에 의해서 할당
    0x02	transactionId는 Network에 의해서 할당
    0x03	ISO/IEC 13818-6에 의해 예약

    Syntax                       No. of bits
-----------------------------------------------------
dsmccAdaptationHeader() {
    adaptationType               8
    for(i = 0;i < (adaptationLength - 1);i++) {
        adaptationDataByte       8
    }
}

• adaptationType

  adaptationType 값	설명
  0x00	ISO/IEC 13818-6 예약
  0x01	DSM-CC Conditional Access adaptation format
  0x02	DSM-CC UserID adaptation format
  0x03~0x7F	ISO/IEC 13818-6 예약
  0x80~0xFF	사용자 정의 adaptationType

  
  

    Syntax                       No. of bits
-----------------------------------------------------
dsmccConditionalAccess() {
    reserved                     8
    caSystemId                   16
    conditionalAccessLength      16
    for(i = 0;i < conditionalAccessLength;i++) {
        conditionalAccessDataByte 8
    }
}

    Syntax                       No. of bits
-----------------------------------------------------
dsmccUserID() {
    reserved                     8
    userID                       20 * 8
}

    Syntax                       No. of bits
-----------------------------------------------------
dsmccDownloadDataHeader() {
    protocolDiscriminator        8 /* = 0x11 */
    dsmccType                    8 /* = 0x03 */
    messageId                    16
    downloadId                   32
    reserved                     8 /* = 0xFF */
    adaptationLength             8
    messageLength                16
    if(adaptationLength > 0) {
        dsmccAdaptationHeader()
    }
}

Message name	messageId 값	설명
DownloadInfoRequest	0x1001	Client requests download parameters
DownloadInfoResponse, DownloadInfoIndication	0x1002	Download Server provides download parameters
DownloadDataBlock	0x1003	Download Server sends one download data block
DownloadDataRequest	0x1004	Client acknowledges downloaded data blocks
DownloadCancel	0x1005	Client or Download Server aborts the download scenario in progress
DownloadServerInitiate	0x1006	Download Server requests Client to initiate a download

    Syntax                       No. of bits
-----------------------------------------------------
DownloadInfoRequest() {
    dsmccMessageHeader()
    bufferSize                   32
    maximumBlockSize             16
    compatibilityDescriptor()
    privateDataLength            16
    for(i = 0;i < privateDataLength;i++) {
        privateDataByte          8
    }
}

    Syntax                       No. of bits
-----------------------------------------------------
DownloadInfoResponse(), DownloadInfoIndication() {
    dsmccMessageHeader()
    downloadId                   32
    blockSize                    16
    windowSize                   8
    ackPeriod                    8
    tCDownloadWindow             32
    tCDownloadScenario           32
    compatibilityDescriptor()
    numberOfModules              16
    for(i = 0;i < numberOfModules;i++) {
        moduleId                 16
        moduleSize               32
        moduleVersion            8
        moduleInfoLength         8
        for(i = 0;i < moduleInfoLength;i++) {
            moduleInfoByte       8
        }
    }
    privateDataLength            16
    for(i = 0;i < privateDataLength;i++) {
        privateDataByte          8
    }
}

• DVB에서는 compatibilityDescriptorLength는 0x0000으로 권장하며 moduleInfo항목이 사용됩니다.
• 각 항목의 수치관계
  • blockSize <= maximumBlockSize
  • windowSize * blockSize <= bufferSize
  • (windowSize - ackPeriod) < (ackLatency * transferRate / blockSize)
  • ackPeriod > (ackLatency * transferRate / blockSize)

    Syntax                       No. of bits
-----------------------------------------------------
DownloadDataBlock() {
    dsmccDownloadDataHeader()
    moduleId                     16
    moduleVersion                8
    reserved                     8 /* = 0xFF */
    blockNumber                  16 /* = 0 ~ 255 */
    for(i = 0;i < N;i++) {
        blockDataByte            8
    }
}

• blockDataByte는 4066bytes로 전송하는것이 빠른접근을 위해서 권장됩니다.
• moduleVersion은 DownloadInfoIndication(DII)의 moduleInfo에서의 moduleVersion과 같은 값입니다.
• moduleVersion은 0~31사이의 값으로 순환되어 Encoding되어야 합니다.
• blockNumber가 0인 것은 첫번째 block을 의미합니다.
• blockNumber는 0~255사이의 값으로 순환되어 Encoding되어야 합니다.

    Syntax                       No. of bits
-----------------------------------------------------
DownloadDataRequest() {
    dsmccDownloadDataHeader()
    moduleId                     16
    blockNumber                  16
    downloadReason               8

    Syntax                       No. of bits
-----------------------------------------------------
DownloadCancel() {
    dsmccMessageHeader()
    downloadId                   32
    moduleId                     16
    blockNumber                  16
    downloadCancelReason         8
    reserved                     8 /* = 0xFF */
    privateDataLength            16
    for(i = 0;i < privateDataLength;i++) {
        privateDataByte          8
    }
}

    Syntax                       No. of bits
-----------------------------------------------------
DownloadServerInitiate() {
    dsmccMessageHeader()
    serverId                     20 * 8 /* [0~20] = 0xFF */
    compatibilityDescriptor()
    privateDataLength            16
    for(i = 0;i < privateDataLength;i++) {
        privateDataByte          8
    }
}

• DVB에서는 serverId 는 모두 0xFF로 채웁니다.
• DVB에서는 compatibilityDescriptorLength는 0x0000으로 권장하며 privateDataByte에 GroupInfoIndication 구조체가 사용됩니다.

    Syntax                       No. of bits
-----------------------------------------------------
GroupInfoIndication() {
    numberOfGroups               16 /* 최대 150 */
    for(i = 0;i < numberOfGroups;i++) {
        groupId                  32
        groupSize                32
        groupCompatibility()
        groupInfoLength          16
        for(i = 0;i < N;i++) {
            groupInfoByte        8
        }
    }
    privateDataLength            16
    for(i = 0;i < privateDataLength;i++) {
        privateDataByte          8
    }
}

Descriptor name	Tag값	DII의 moduleInfo에 사용가능유무	DSI의 groupInfo에 사용가능유무	설명
reserved	0x00
Type	0x01	M	M	type descriptor of data
Name	0x02	R	R	name descriptor of data
Info	0x03	O	O	textual description
module_link	0x04	R		concatenated data module
CRC32	0x05	M		Cyclic Redundancy Code (CRC)
Location	0x06	R	R	location of data
est_download_time	0x07	O	O	estimated download time
group_link	0x08		R	links DII messages descripting a group
compressed_module	0x09	M		indicates compression structure
SSU_module_type	0x0A	O		DVB SSU
subgroup_association	0x0B		O	DVB SSU

    Syntax                       No. of bits
-----------------------------------------------------
type_descriptor() { /* moduleInfoByte(MANDATORY), groupInfoByte(MANDATORY) */
    descriptor_tag               8 /* = 0x01 */
    descriptor_length            8
    for(i = 0;i < N;i++) {
        text_char                8
    }
}

    Syntax                       No. of bits
-----------------------------------------------------
name_descriptor() { /* moduleInfoByte(RECOMMENDED), groupInfoByte(RECOMMENDED) */
    descriptor_tag               8 /* = 0x02 */
    descriptor_length            8
    for(i = 0;i < N;i++) {
        text_char                8
    }

    Syntax                       No. of bits
-----------------------------------------------------
info_descriptor() { /* moduleInfoByte, groupInfoByte */
    descriptor_tag               8 /* = 0x03 */
    descriptor_length            8
    ISO_639_language_code        24
    for(i = 0;i < N;i++) {
        text_char                8
    }

    Syntax                       No. of bits
-----------------------------------------------------
module_link_descriptor() { /* moduleInfoByte(RECOMMENDED) */
    descriptor_tag               8 /* = 0x04 */
    descriptor_length            8
    position                     8
    module_id                    16

    Syntax                       No. of bits
-----------------------------------------------------
CRC32_descriptor() { /* moduleInfoByte(MANDATORY) */
    descriptor_tag               8 /* = 0x05 */
    descriptor_length            8
    CRC32                        32 /* CRC32 over all data's in one DDB */
}

    Syntax                       No. of bits
-----------------------------------------------------
location_descriptor() { /* moduleInfoByte(RECOMMENDED), groupInfoByte(RECOMMENDED) */
    descriptor_tag               8 /* = 0x06 */
    descriptor_length            8
    location_tag                 8

    Syntax                       No. of bits
-----------------------------------------------------
est_download_time_descriptor() { /* moduleInfoByte, groupInfoByte */
    descriptor_tag               8 /* = 0x07 */
    descriptor_length            8
    est_download_time            32 /* seconds */

    Syntax                       No. of bits
-----------------------------------------------------
group_link_descriptor() { /* groupInfoByte(RECOMMENDED) */
    descriptor_tag               8 /* = 0x08 */
    descriptor_length            8
    position                     8
    group_id                     32

    Syntax                       No. of bits
-----------------------------------------------------
Compressed_module_descriptor() { /* moduleInfoByte(MANDATORY) */
    descriptor_tag               8 /* = 0x09 */
    descriptor_length            8
    compression_method           8
    original_size                32

    Syntax                       No. of bits
-----------------------------------------------------
DSM-CC section() {
    table_id                     8 uimsbf
    section_syntax_indicator     1 bslbf
    private_indicator            1 bslbf
    reserved                     2 bslbf
    dsmcc_section_length         12 uimsbf
    table_id_extension           16 uimsbf
    reserved                     2 bslbf
    version_number               5 uimsbf
    current_next_indicator       1 bslbf
    section_number               8 uimsbf
    last_section_number          8 uimsbf
    if(table_id == 0x3A) { /* DSM-CC Sections containing multi-protocol encapsulated data */
        LLCSNAP()
    }
    else if(table_id == 0x3B) { /* DSM-CC Sections containing U-N Messages, except Download Data Messages */
        userNetworkMessage()
    }
    else if(table_id == 0x3C) { /* DSM-CC Sections containing Download Data Messages */
        downloadDataMessage()
    }
    else if(table_id == 0x3D) { /* DSM-CC Sections containing Stream Descriptors */
        DSMCC_descriptor_list() {
            for(i = 0;i < N;i++) {
                stream_descriptor()
            }
        }
    }
    else if(table_id == 0x3E) { /* DSM-CC Sections containing private data */
        for(i = 0;i < (dsmcc_section_length - 9);i++) {
            private_data_byte
        }
    }
    if(section_syntax_indicator == '0') {
        checksum                 32 uimsbf
    }
    else {
        CRC_32                   32 rpchof
    }
}