IEC 61937-13:2018 pdf download

IEC 61937-13:2018 pdf download.Digital audio – Interface for non-linear pcm encoded audio bitstreams applying IEC 60958
1 Scope
This part of IEC 61 937 specifies the method to convey non-linear PCM bitstreams encoded according to the MPEG-H 3D Audio format.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60958 (all parts), Digital audio interface IEC 61 937-1 , Digital audio – Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 – Part 1: General IEC 61 937-2, Digital audio – Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 – Part 2: Burst-info ISO/IEC 23008-3:201 5, Information technology – High efficiency coding and media delivery in heterogeneous environments – Part 3: 3D audio
3 Terms, definitions and abbreviated terms
For the purposes of this document, the terms and definitions given in IEC 61 937-1 , IEC 61 937-2 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 Terms and definitions 3.1 .1 audio sample rate sampling frequency of the linear PCM audio samples before encoding and after decoding 3.1 .2 frame length number of linear PCM audio samples per MPEG-H 3D Audio data frame Note 1 to entry: MPEG-H 3D Audio can operate in several modes using any of 1  024, 2 048, 4 096, 768, 1  536 or 3 072 linear PCM audio samples per MPEG-H 3D Audio data frame.3.1 .3 latency delay time of an external audio decoder to decode an MPEG-H 3D Audio data-burst defined as the sum of two values – the receiving delay time and the decoding delay time 3.1 .4 MHASPacketLabel field in an MPEG-H 3D Audio stream packet that provides an indication on which packets belong together 3.1 .5 MHASPacketLength field in an MPEG-H 3D Audio stream packet that indicates the length of the MHASPacketPayload in bytes 3.1 .6 MHASPacketPayload payload of the MHASPacket 3.1 .7 MHASPacketType field in an MPEG-H 3D Audio stream packet that specifies the payload type in the packet given in ISO/IEC 23008-3:201 5, 1 4.3.1 3.1 .8 MPEG-H 3D Audio data frame sequence of one or more MPEG-H 3D Audio stream packets (MHAS packets), as defined in ISO/IEC 23008-3:201 5, Clause 1 4 that represents frame length (or fewer) linear PCM audio samples 3.1 .9 MPEG-H 3D Audio stream packet building blocks of an MPEG-H 3D audio stream that comprises an MHASPacketType field, an MHASPacketLabel field, an MHASPacketLength field, and an MHASPacketPayload 3.1 .1 0 MPEG-H 3D Audio Stream self-contained stream format to transport ISO/IEC 23008-3 (MPEG-H 3D Audio) data as defined in ISO/IEC 23008-3:201 5, Clause 1 4 3.1 .1 1 PACTYP_MPEGH3DACFG MHASPacketType registration for an MHAS Packet that embeds an MPEG-H 3D audio configuration structure in the MHASPacketPayload as defined in ISO/IEC 23008-3:201 5, 1 4.4 3.1 .1 2 PACTYP_MPEGH3DAFRAME MHASPacketType registration for an MHAS Packet that embeds a frame of MPEG-H 3D audio in the MHASPacketPayload as defined in ISO/IEC 23008-3:201 5, 1 4.4 3.1 .1 3 PACTYP_AUDIOSCENEINFO MHASPacketType registration for an MHAS Packet that embeds an MPEG-H 3D audio scene information structure in the MHASPacketPayload as defined in ISO/IEC 23008-3:201 5, 1 4.4
If regular audio data-bursts are not being transmitted due to, for example, a pause condition, it is recommended to use pause data-bursts to fill such stream gaps. The repetition period of the pause data-bursts should be selected according to Table 2. If other repetition periods are necessary to precisely fill the stream gap length, or to meet the requirement on audio data- burst spacing (see IEC 61 937-1 ), pause data-bursts may have other lengths. When a stream gap in an audio stream is filled by a sequence of pause data-bursts, the Pa of the first pause data-burst shall occur after exactly that number of IEC 60958 frames as indicated by the MPEG-H 3D Audio data-frame length in conjunction with the data-type- dependent information from Table 4. It is recommended that the sequence of pause data- bursts that fills the stream gap should continue from this point until the Pa of the first audio data-burst that follows the stream gap, or as close as possible to that point, considering the specific IEC 60958 frame length of the pause data-burst with respect to the MPEG-H 3D Audio data frame length. The repetition-period-length parameter contained in the pause data- burst is intended to be interpreted by the receiver as an indication of the number of decoded PCM samples that are missing (due to the resulting audio gap).