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e16d334f11519b9671e26952047d356b | 103 491 | 4.2.1 Construction of a DTS-UHD Audio Frame | The DTS-UHD stream is a sequence of DTS-UHD frames. The DTS-UHD frames consist of three major construction elements: 1) Frame Table Of Contents (FTOC) - This element allows a decoder to navigate directly to elements of interest with the frame. 2) Metadata Chunk elements. 3) Audio Chunk elements. Figure 4-1: DTS-UHD Fra... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.2.2 Frame Table of Contents (FTOC) | The main components of the FTOC are the Sync Word (the first 4 bytes of the FTOC), which indicates whether the frame is a sync frame or non-sync frame, default presentations and dependency information, and the navigation tables to the metadata chunks and audio chunks being delivered in the frame payload. The FTOC is th... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.2.3 Sync Frames | The decoder does not need any information from previous or future frames to produce a frame of output L-PCM samples from a sync frame. All parameters necessary to unpack metadata and audio chunks, describe audio chunks, render and process audio samples and generate a frame of L-PCM samples can be found within the paylo... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.2.4 Non-sync Frames (Predictive Frames) | A non-sync frame permits both metadata chunks and audio chunks to minimize payload size by only sending parameters that have changed in value since the previous frame or sync frame. All parameters that are not re-transmitted are assumed to maintain their previous value. Any value or set of values may be updated in a no... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3 Carriage of Metadata | |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3.1 Organization of Metadata | Metadata for multiple objects and object groups is packed together within an associated metadata chunk. Each chunk of a particular type has its associated audio presentation index. Notice that chunks of different metadata chunk types may have the same audio presentation index; however, two metadata chunks of the same t... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3.2 Metadata Chunks | Metadata chunks carry the full description of the audio data chunks and how decoded audio shall be rendered for final audio presentation. Additional types of metadata that may be useful for categorization of an audio presentation, support of some post-processing functionality, etc., may also be carried within the metad... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3.3 Fundamental Components of the Metadata Chunk | |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3.3.1 Metadata Chunk: Data | The data field contains the data of the chunk. The format of the data is specific to the type of chunk. Currently (as of the present document) only ChunkType = 0x01 is defined. The details of this chunk are in clause 7. |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3.3.2 Reserved and Byte Align Fields | Reserved fields and fields for padding to the next byte boundary are defined at the end of each metadata chunk. These fields are used to insure byte alignment for the following data structure (e.g. another metadata chunk), and for extending the metadata chunk with new data structures. The decoder shall always assume th... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.3.3.3 Metadata Chunk CRC Word | If the CRC flag (transmitted within FTOC: Metadata and Audio Chunk Navigation Parameters) corresponding to particular metadata chunk is TRUE, the metadata chunk CRC (16-bit) word is transmitted in order to allow verification of the metadata chunk data. This CRC value is calculated over metadata fields, starting from an... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.4 Audio Chunks | Audio chunks carry the compressed audio samples. Audio samples may be representing speaker feeds, waveforms associated with a 3D audio object, waveforms associated with a sound field audio representation, or some other valid audio representation. The associated metadata chunk fully describes the way a particular audio ... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.5 Organization of Streams | |
e16d334f11519b9671e26952047d356b | 103 491 | 4.5.1 Objects, Object Groups, Presentations | The fundamental unit of a DTS-UHD stream is the object. The simplest example of a DTS-UHD stream would be a stream containing one object. For example, one stereo audio presentation, or even a single 5.1 or 7.1 channel presentation, could be handled in such a manner. Object Groups provide a mechanism to associate object... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.5.2 Properties of Objects | The object metadata carries parameters needed to: • Uniquely identify an object within a DTS-UHD stream. • Point to associated audio waveforms. • Describe the audio object properties necessary to render associated audio waveforms. • Assign whether the Default Playback status of the object is Active or Silent. • Describ... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.5.3 Properties of Object Groups | The object group metadata carries parameters needed to: • Uniquely identify an object group within one DTS-UHD stream by means of a unique object ID. • Indicate which objects belong to the group by means of a list of object IDs. • Assign whether the default status is to be played or to be silent. • Indicate which objec... |
e16d334f11519b9671e26952047d356b | 103 491 | 4.5.4 Audio Presentations | Multiple audio presentations may be defined within a single DTS-UHD bitstream. Each audio presentation has unique audio presentation index within a stream and may be categorized as: • selectable: where the playback of this presentation does not need playback of any of the audio presentations with the higher audio prese... |
e16d334f11519b9671e26952047d356b | 103 491 | 5 DTS-UHD Header Tables and Helper Functions | |
e16d334f11519b9671e26952047d356b | 103 491 | 5.1 Overview | This clause includes conversion constants and parameter tables to assist the description and interpretation of the metadata. Additionally, some essential APIs are described for initiating a decoder session. |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2 Constants, Tables and Helper Functions | |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.1 Fixed Point Constants | Table 5-1 defines some Q format number constants used in rational number calculations. Table 5-1: Table of Conversion Constants Mnemonic Value Meaning FOURTEEEN_DB_LIN_Q15 180613 10^(14/20)* (1 << 15) + (1 << 14) ONE_IN_Q15 32768 1 << 15 SQRT2Q1DOT15 62725 √2 × (1 << 15) + (1 << 14) |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2 Look-up Tables | |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2.1 Scale Factor Table | const uint unScaleFactorsTable[] = { 0, 41, 52, 65, 82, 104, 130, 164, 207, 260, 328, 413, 519, 654, 823, 1036, 1163, 1305, 1464, 1642, 1843, 2068, 2320, 2603, 2920, 3277, 3677, 4125, 4629, 5193, 5827, 6172, 6538, 6925, 7336, 7771, 8231, 8719, 9235, 9783, 10362, 10976, 11627, 12315, 13045, 13818, 14637, 15504, 16423, 1... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2.2 Long Term Loudness Measure Table | const float rLongTermLoudnessMeasure_Table[] = { -40.0000f, -39.0000f, -38.0000f, -37.0000f, -36.0000f, -35.0000f, -34.0000f, -33.0000f, -32.0000f, -31.0000f, -30.0000f, -29.5000f, -29.0000f, -28.5000f, -28.0000f, -27.5000f, -27.0000f, -26.7500f, -26.5000f, -26.2500f, -26.0000f, -25.7500f, -25.5000f, -25.2500f, -25.000... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2.3 Per-Object Long Term Loudness Measure Table | Entries in the rPerObjLongTermLoudnessMeasure_Table[] represent per-object long term loudness measures in dB relative to full scale. const float rPerObjLongTermLoudnessMeasure_Table[] = { -61.0000f, -58.0000f, -55.0000f, -52.0000f, -49.0000f, -46.0000f, -44.0000f, -42.0000f, -40.0000f, -39.0000f, -38.0000f, -37.0000f, ... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2.4 Quantization Table for DRC Fast Attack Smoothing Constant | The extracted 6-bit index is mapped to 64 values in the range [0 to 25] representing the value of DRC fast attack smoothing constant. const float rDRCFastAttackTable[] = { 0.0000f, 0.2000f, 0.4000f, 0.6000f, 0.8000f, 1.0000f, 1.2000f, 1.4000f, 1.6000f, 1.8000f, 2.0000f, 2.2000f, 2.4000f, 2.6000f, 2.8000f, 3.0000f, 3.20... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2.5 Quantization Table for DRC Fast Release Smoothing Constant | The extracted 6-bit index is mapped to 64 values in the range [0 to 1 000] representing the DRC fast release smoothing constant. const float rDRCFastReleaseTable[] = { 0.0f, 5.0f, 10.0f, 15.0f, 20.0f, 25.0f, 30.0f, 35.0f, 40.0f, 45.0f, 50.0f, 55.0f, 60.0f, 65.0f, 70.0f, 75.0f, 80.0f, 85.0f, 90.0f, 95.0f, 100.0f, 110.0f... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.2.6 Quantization Table for DRC Slow to Fast Threshold | Entries in the rDRCSlow2FastThrshld_Table[] represent the threshold values expressed in the power domain in range [1 to 0,001]. const float rDRCSlow2FastThrshld_Table[] = { 1.0000000f, 0.8912509f, 0.7943282f, 0.7079458f, 0.6309574f, 0.5623413f, 0.5011872f, 0.4731513f, 0.4466836f, 0.4216965f, 0.3981072f, 0.3758374f, 0.3... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3 Helper Functions | |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3.1 ExtractVarLenBitFields | This routine is used to extract a field of variable length. The extracted field is interpreted as an unsigned integer (uint). The length of a field depends on the prefix code that is transmitted prior to the field itself and the values in the 4 element table passed through the input argument uctable[].This function is ... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3.2 UpdateCode | Each parameter has its presence flag (m_bParamPresent) that is transmitted only if bSyncOrFirstFrameFlag is TRUE. If m_bParamPresent is FALSE, then no other fields related to this parameter are transmitted in any other frame. Instead, this parameter is by default set to either: • m_tSyncFramePredefValue if the m_bSyncF... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3.3 CountBitsSet_to_1 | This function calculates the number of bits set to 1 in an unsigned 32-bit mask. This function is described in Table 5-4. Table 5-4: CountBitsSet_to_1 Syntax uint CBitStream::CountBitsSet_to_1(uint uintMask) { uint nb=0; for (uint n=0; n<32; n++) { nb = ((uintMask>>n) & 1) ? (nb+1) : nb; } return nb; } |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3.4 GetPtrToCurrentByte | Function to get pointer to the current byte in the stream buffer. This function is described in Table 5-5. Table 5-5: GetPtrToCurrentByte Syntax uchar * GetPtrToCurrentByte(void) { return m_ucStreamBuffer.data() + (m_unBitCounter >> 3); } |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3.5 GetBitCounter | Return the current bit counter. This function is described in Table 5-6. Table 5-6: GetBitCounter Syntax uint GetBitCounter(void){ return m_unBitCounter; } |
e16d334f11519b9671e26952047d356b | 103 491 | 5.2.3.6 AdvanceBitReadPointer | This function advances the bitstream read pointer, allowing the parser to skip some number of bits. This function is described in Table 5-7. Table 5-7: AdvanceBitReadPointer Syntax void AdvanceBitReadPointer(uint unNumBits) { m_unBitCounter += unNumBits; } ETSI ETSI TS 103 491 V1.2.1 (2019-05) 42 |
e16d334f11519b9671e26952047d356b | 103 491 | 5.3 Interfaces for Extracting Metadata Frames | |
e16d334f11519b9671e26952047d356b | 103 491 | 5.3.1 Overview of APIs | APIs for unpacking frames of metadata depend on the type of audio presentation selection. These parameters are dependent on the listening environment: • unOutChMask is from the player API call set according to the user's selected playback configuration; • unMaxObjects is a decoder configuration setting based on that pa... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.3.2 Audio Presentation Selection | The class for CAuPresSelectAPI is described in Table 5-8. Table 5-8: CAuPresSelectAPI Syntax class CAuPresSelectAPI { private: public: // API parameters uchar m_ucAudPresInterfaceType; // Type of API that was used to select desired audio presentation bool m_bEnblDefaultAuPres; uchar m_ucDesiredAuPresIndex; std::vector<... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.3.3 Play Default Presentation | Enable or disable the default audio presentation; the default objects within that presentation will be played or outputs will be muted respectively. Pseudo-code for this call is shown in Table 5-9. ETSI ETSI TS 103 491 V1.2.1 (2019-05) 43 Table 5-9: Default Presentation Syntax Reference void CMetaDataFrame::UnpackMDFra... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.3.4 Play Selected Presentation | Select a desired audio presentation other than the default presentation, and the default objects within that presentation will be played. Pseudo-code for this call is shown in Table 5-10. Table 5-10: Selected Presentation Syntax Reference void CMetaDataFrame::UnpackMDFrame_API(uchar ucDesiredAuPresIndex, uint unOutChMa... |
e16d334f11519b9671e26952047d356b | 103 491 | 5.3.5 Play from a List of Objects | Play from a specified list of objects. In this case unDepAuPresMask indicates that all presentations are active, so the decoder shall determine which audio presentations carry objects from m_AuPrSelectAPI_SampledatSyncFrm.m_unDesiredObjIDList. Pseudo-code for this call is shown in Table 5-11. Check whether any of the o... |
e16d334f11519b9671e26952047d356b | 103 491 | 6 DTS-UHD Metadata Header Parsing | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.1 Overview | This clause describes the metadata header, including the frame table of contents (FTOC). ETSI ETSI TS 103 491 V1.2.1 (2019-05) 44 |
e16d334f11519b9671e26952047d356b | 103 491 | 6.2 UnpackMDFrame | This is the function for unpacking a frame of metadata where desired objects to be played are selected based on the type of API interface used (as indicated by m_ucAudPresInterfaceType) and the associated parameter for particular interface type. The class for CMetaDataFrame is shown in Table 6-1. Pseudo-code describing... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3 Functions and Tables Supporting UnpackMDFrame | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.1 ResetMDChunks | Reset extracted metadata chunks according to the pseudo-code in Table 6-3. Table 6-3: ResetMDChunks Syntax void CMetaDataFrame::ResetMDChunks(void) { // Reset 0x01 Metadata Chunks for (uint nn = 0; nn < m_ucMaxNumAuPres; nn++) { if (m_ppCMD0x01[nn] != NULL) { delete m_ppCMD0x01[nn]; m_ppCMD0x01[nn] = NULL; } } } |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.2 Metadata Chunk Types | The Chunk_ID is used to identify the type of data stored in the chunk according to the Metadata Chunk Types shown in Table 6-4. The Chunk_ID is an 8-bit unsigned integer. ETSI ETSI TS 103 491 V1.2.1 (2019-05) 47 Multiple instances of the same chunk type (same Chunk_ID) are possible: • when each instance is associated w... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.3 Audio Presentation Index | Audio presentation index is part of the 0x01 metadata chunk and indicates the audio presentation index that is associated with this metadata chunk. The index values can be up to 0, 4, 20 or 31 depending on the transmitted variable length code of 1, 4 or 7 bits. Pseudo-code to extract the audio presentation index is sho... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.4 ExtractMDChunkObjIDList | Extract the number of objects defined within a metadata chunk and the list of object IDs whose metadata is defined in the current frame of the MD chunk. The list is stored in vector m_punObjectIDList where m_punObjectIDList.size() indicates the number of objects. Pseudo-code for ExtractMDChunkObjIDList() is shown in Ta... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.5 Parameters in ExtractMDChunkObjIDList | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.5.1 m_unNumObjects | Total number of objects and object group definitions defined in this metadata chunk. This parameter can change from frame to frame. When bFullChannelBasedMixFlag is TRUE, m_unNumObjects=1 by default. When bFullChannelBasedMixFlag is FALSE m_unNumObjects is packed as a variable length (4, 6, 9 or 11 bits) code. Dependin... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.5.2 unNumBitsforObjID | This 1-bit field is extracted from the stream, for each of m_unNumObjects objects, only if the bFullChannelBasedMixFlag is FALSE. The unNumBitsforObjID is either 4 or 8 corresponding to the number of bits that are used to represent an object ID. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.5.3 m_unObjectID | This field is extracted from the stream, for each of m_unNumObjects objects, only if the bFullChannelBasedMixFlag is FALSE. The m_unObjectID represents the unique object ID that can range from 0 to 15 (if unNumBitsforObjID = 4) or from 0 to 255 (if unNumBitsforObjID = 8). For full channel-based mixes (bFullChannelBased... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.6 Update Object List | A function to create or update an explicitly requested object list for a particular audio presentation based on: • the global object list, provided by the system layer (m_AuPrSelectAPI_SampledatSyncFrm.m_unDesiredObjIDList); and • the list of extracted objects in this 0x01 MD chunk (m_punObjectIDList[]) is shown in Tab... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.7 Reserved and Byte Alignment Fields | To allow for the addition of a new metadata field within this chunk, all decoders shall track the number of bits extracted within this metadata chunk, compare it against the metadata chunk size and navigate past any remaining bits of the present metadata chunk. ETSI ETSI TS 103 491 V1.2.1 (2019-05) 50 |
e16d334f11519b9671e26952047d356b | 103 491 | 6.3.8 Metadata Chunk CRC | The metadata chunk CRC (16-bit) value is transmitted in order to verify the chunk data. This CRC value is calculated over metadata fields starting from and including the MD Chunk ID and up to and including the byte alignment field prior to the CRC word (unMDChunkSize-2 bytes in total). The decoder shall: • Calculate th... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4 Frame Table of Contents (FTOC) | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.1 Overview of the FTOC | DTS-UHD frames have a single Frame Table of Contents to navigate to the Metadata Chunks and Audio Chunks. Table 6-11 describes how to parse this structure. These parameters apply to the entire stream (i.e. all audio and metadata chunks and audio presentations) and are transmitted in the stream only in the sync frame (i... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.2 FTOC Class Parameters | The FTOC Class Parameters are shown in Table 6-10. Extracting the FTOC parameters from the bitstream is shown in Table 6-11. Table 6-10: CFrmTblofContent Syntax class CFrmTblOfContent { private: CBitStream *m_pBitStream; // Pointer to the bitstream class uint m_unTotalFramePayloadinBytes; // Frame payload in bytes // S... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.3 Extract FTOC | Table 6-11: ExtractFTOC Syntax Reference bool CFrmTblOfContent::ExtractFTOC(CAuPresSelectAPI AuPresSelectAPI, CAuPresSelectAPI *pAuPresSelectAPI_SampledatSyncFrm, CCrc16 *pCCrc16) { uint unSyncWord; uint unBitCounter = GetBitCounter(); // Get initial Position uchar *ucpStreamBuff = m_pBitStream->GetPtrToCurrentByte(); ... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.4 Parameters for FTOC | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.4.1 unSyncWord | This field represents a 32-bit sync word that, when expressed in hexadecimal format, is either 0x40411BF2 for sync frames or 0x71C442E8 in non-sync frames. ETSI ETSI TS 103 491 V1.2.1 (2019-05) 53 |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.4.2 bSyncFrameFlag | The boolean m_bSyncFrameFlag is set TRUE if the sync word indicates the present frame being decoded is a sync frame, otherwise it is set to FALSE. Decoders shall only attempt to initialize on a sync frame. After acquiring synchronization every frame shall be checked for the sync word to determine if the frame is a sync... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.4.3 unFTOCPayloadinBytes | The value of unFTOCPayloadinBytes indicates the size, in bytes, of data in FTOC which starts from the FTOC sync word through (and including) the FTOC CRC word (if present). The variable length coding allows for FTOC payload of 32, 288, 1 312 or 5 408 bytes. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.5 Stream Parameters | The stream parameters are extracted as shown in Table 6-12. Table 6-12: ExtractStreamParams Syntax Reference // Input Arguments: // ucpStreamBuff, pointer to the first byte of FTOC data block // pCCrc16, pointer to an instance of CRC16 class // void CFrmTblOfContent::ExtractStreamParams(uchar *ucpStreamBuff, CCrc16 *pC... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6 Parameters for ExtractStreamParams | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.1 Full Channel-based Mix Flag | If m_bFullChannelBasedMixFlag = TRUE, then the content represents a full channel mask-based audio presentation (i.e. stereo, 5.1, 11.1 mix without objects). This implies the following: • the stream version.revision number is 2.0; • the number of audio presentations is 1; • the number of audio chunks is 1; • the number ... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.2 CRC Test | When m_bFullChannelBasedMixFlag = TRUE, the FTOC CRC16 word is transmitted in the stream only in the sync frames. Consequently for this case the CRC check is performed only in sync frames. When m_bFullChannelBasedMixFlag = FALSE, the FTOC CRC16 word is transmitted in every frame, so the CRC check is performed in all fr... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.3 Stream Version Number | The stream version number is in a decimal representation in form of x.y where x represents a major version number and y represents a minor revision of the x version. ETSI ETSI TS 103 491 V1.2.1 (2019-05) 55 A DTS-UHD decoder implementation, with its version as indicated by the REVISION_NUMBER, shall do the following: •... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.4 Base Duration | m_unBaseDuration indicates the number of clock cycles in the base duration period. The 2-bit index is used to distinguish between 4 different base duration periods as indicated in Table 6-13. Table 6-13: Base Duration index BaseDuration (samples) 0 512 1 480 2 384 3 Reserved |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.5 Frame Duration | m_unFrameDuration indicates the number of clock cycles (as defined by the m_unClockRateInHertz) in the frame duration period. It is derived from an extracted 3-bit multiplier and m_unBaseDuration. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.6 Clock Rate | The clock rate is used to calculate the audio sampling rate. m_unClockRateInHz is a 2-bit field representing the clock rate in Hz according to Table 6-14. Table 6-14: Clock Rate code (from bitstream) ClockRate (Hz) 0 32 000 1 44 100 2 48 000 3 Unused |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.7 Time Code Parameters | The m_TimeStamp.m_bUpdateFlag indicates if the time code parameter is transmitted in the stream. This flag is extracted/set within the m_TimeStamp.UpdateCode(). UpdateCode() is explained in clause 5.2.3.2. The call to m_TimeStamp.UpdateCode() returns the status of m_TimeStamp.m_bUpdateFlag. If m_TimeStamp.m_bUpdateFlag... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.8 Audio Sampling Rate | m_unAudioSamplRateInHz represents the audio sampling rate in Hz. The 2-bit parameter read from the FTOC Parameters is used as a power of 2 (2^n) that takes results in a multiplier of 1, 2, 4 or 8. This is multiplied by the clock rate, m_unClockRateInHz. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.9 Number of Audio Samples | The number of audio samples in the metadata frame duration period is calculated as m_unFrameDuration * m_unAudioSamplRateInHz / m_unClockRateInHz. In the nominal case, the audio frame duration period in seconds and the metadata frame duration period in seconds are the same. However, there are exceptions to this nominal... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.10 Reserved Flag | m_reservedFlag shall be read when m_bFullChannelBasedMixFlag = FALSE. If m_bFullChannelBasedMixFlag = TRUE then this parameter is not present. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.6.11 Object Interactivity Limits Present Flag | m_bInteractObjLimitsPresent shall be read when m_bFullChannelBasedMixFlag = FALSE. If m_bFullChannelBasedMixFlag = TRUE then this parameter is not present. When m_bInteractObjLimitsPresent = TRUE, then the metadata for limiting the user control of interactive objects is present in the stream. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.7 ResolveAudPresParams | Within every selectable audio presentation, a set of audio presentation parameters is transmitted in the stream. Each set consists of the parameters describing the default dependency of selected presentation on any audio presentations of the lower index. This is shown in Table 6-15. Table 6-15: ResolveAudPresParams Syn... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.8 Parameter for ResolveAudPresParams | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.8.1 Number of Audio Presentations | The number of audio presentations defined in the stream is coded with 4 variable length codes (1, 4, 7 or 8 bit length), allowing for 1, 5, 21 or 32 audio presentations to be defined in total. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.9 Extract Audio Presentation Parameters | ExtractAudPresParams is shown in Table 6-16. Table 6-16: ExtractAudioPresParams Syntax Reference void CFrmTblOfContent::ExtractAudPresParams (uchar ucDesiredSelectAuPresIndex, bool bSaveParameters4AllPresentations) { uint unDepAuPresMask; uchar ucSelectablePresCounter = 0; //number of selectable audio presentations if ... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.10 Parameters for ExtractAudPresParams | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.10.1 bAudPresSelectableFlag | This 1-bit field is transmitted in the stream only if the m_bSyncFrameFlag is TRUE. The presentation selectable flag indicates if an audio presentation with all its dependent lower indexed presentations (as indicated by m_unDepAuPresMask) is playable without any higher indexed presentations. In particular when: • bAudP... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.10.2 unDepAuPresMask | This field is transmitted only if the m_bSyncFrameFlag is TRUE and only for selectable presentations (i.e. bAudPresSelectableFlag = TRUE). The ucDepAuPresMask is a bit mask describing which of the lower indexed presentations shall be by default played together with the current selectable audio presentation. Since a sel... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.10.3 Explicit Object List Present Flag | This 1-bit field is transmitted only if the m_bSyncFrameFlag is TRUE and only for selectable presentations (i.e. bAudPresSelectableFlag = TRUE). For each dependent presentation, extract a bit that indicates if the default objects within that presentation shall be played (bit set to '0') or there exists an explicitly de... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.11 ExtractExplicitObjectsLists | The following fields are transmitted in the stream for each lower indexed presentation that has its corresponding bit within unDepAuPresExplObjListMask set to "1" according to the pseudo-code in Table 6-17. Table 6-17: ExtractExplicitObjectsLists Syntax Reference void CFrmTblOfContent::ExtractExplicitObjectLists( uint ... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.12 Parameters for ExtractExplicitObjectLists | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.12.1 Explicit Object List Update Flag | This 1-bit flag is transmitted in the stream only if the m_bSyncFrameFlag is FALSE. In the case where m_bSyncFrameFlag is TRUE, the explicit object list update flag is set to TRUE by default. When this update flag is TRUE it indicates that the explicit object list mask is transmitted in the current frame. Otherwise, th... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.12.2 Explicit Object List Mask | This variable length field represents an object list mask where each bit corresponds to an object within specific lower indexed audio presentation in the order in which objects are packed in the stream. When the bit is set to "1" it indicates that the playback of the corresponding object is requested. NOTE: This list o... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.12.3 Metadata Describing Presentation Scaling for Different Playback Configurations | This metadata block is present only in the sync frames (m_bSyncFrameFlag is TRUE) and only for the audio presentations with bAudPresSelectableFlag equal to TRUE. This metadata block defines audio presentation scaling tailored for different playback configurations as described in clause 7.5.1. |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.12.4 Extract and Save All Audio Presentation Parameters | ExtractAudPresParams() is a function to extract and save all audio presentation parameters, as shown in Table 6-18. The function is only executed when the stream decoder is configured with an object list. In this case there is no preferred playable presentation and the list of desired objects is provided. Since the par... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.13 Navigation Parameters for Metadata and Audio Chunks | The prototype for the CAudioChunkNaviParams class is shown in Table 6-19. Table 6-19: Audio Chunk Navigation - Class Parameters Syntax class CAudioChunkNaviParams { private: public: uint m_unAudioChunkPackinIndex; // Chunk's packing index within the current frame payload uint m_unAudioChunkID; // A registered audio chu... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14 Parameters for ExtractChunkNaviData | |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.1 Number of Metadata Chunks | This field indicates the number of metadata chunks present in the current frame. In the case where m_bFullChannelBasedMixFlag is TRUE, the number of metadata chunks is not transmitted and takes the default value of 1 in sync frames and 0 in non-sync frames. In the case where m_bFullChannelBasedMixFlag is FALSE, 4 varia... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.2 Sizes of Metadata Chunks | These fields indicate the size in bytes of each metadata chunk present in the current frame. Four variable length codes (7, 11, 15 or 18 bits in length) are used to allow sizes of up to 63, 575, 4 671 or 32 767 bytes respectively. ETSI ETSI TS 103 491 V1.2.1 (2019-05) 63 |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.3 Metadata Chunks CRC Flag | Each metadata chunk has a corresponding 1-bit flag indicating the presence of 16-bit CRC at the end of metadata chunk payload. The m_pbMDChunkCRCFlags[nmdc] stores the metadata CRC flag for metadata chunk with index nmdc. The flag is not transmitted if m_bFullChannelBasedMixFlag is TRUE and instead m_pbMDChunkCRCFlags[... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.4 Number of Audio Chunks | This field indicates the number of audio chunks present in the current frame. When m_bFullChannelBasedMixFlag is TRUE, the number of audio chunks is not transmitted and takes the default value of 1. When m_bFullChannelBasedMixFlag is FALSE, 4 variable length codes (3, 6, 9 or 11 bits in length) are used to allow encodi... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.5 Audio Chunk Handler ResetList | Resets all list members but keeps the list size, as demonstrated in Table 6-21. Table 6-21: ResetList Syntax void CAudioChunkListHandler::ResetList(void) { for (uint unli = 0; unli < m_unHigestIndex; unli++) { m_pCAudioChunksNaviParams[unli].m_bAudioChunkPresent = FALSE; m_pCAudioChunksNaviParams[unli].m_unAudioChunkID... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.6 ResetAudioChunkPresentFlags | Resets m_pCAudioChunksNaviParams[].m_bAudioChunkPresent as shown in Table 6-22. Table 6-22: ResetAudioChunkPresentFlags Syntax void CAudioChunkListHandler::ResetAudioChunkPresentFlags(void) { for (uint unli = 0; unli < m_unHigestIndex; unli++) { m_pCAudioChunksNaviParams[unli].m_bAudioChunkPresent = FALSE; } } // End R... |
e16d334f11519b9671e26952047d356b | 103 491 | 6.4.14.7 Audio Chunk Index | This field indicates an audio chunk index, which is unique for each audio chunk. This index is used for referencing audio chunks within the metadata chunks. This index has a constant value over the life time of an audio chunk. Four variable length codes (3, 6, 9 or 11 bits in length) are used to allow chunk index value... |
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