IEC 60958-5:2021 pdf download – Digital audio interface – Part 5: Consumer application enhancement.
1 Scope This part of IEC 60958 enhances the consumer application of the interface for the interconnection of digital audio equipment defined in IEC 60958-1 and IEC 60958-3, introducing: – multichannel; – multi-stream; – high-resolution; – multimedia extension; – related applications. NOTE IEC 60958-3 specifies a consumer application to carry stereophonic programmes with a resolution of up to 24 bits per sample. This part of IEC 60958 enhances the application, allowing programmes with up to 64 channels, 64 bits per sample, and two simultaneous streams. 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 60958-1:20— 1 , Digital audio interface – Part 1: General IEC 60958-3:20— 2 , Digital audio interface – Part 3: Consumer applications IEC 62574:2020, Audio, video and multimedia systems – General channel assignment of multichannel audio ISO/IEC 23001-8:2016, Information technology – MPEG systems technologies – Part 8: Coding- independent code points 3 ITU-R BS.2094-1:2017, Common definitions for the audio definition model ITU-R BS.2051-2:2018, Advanced sound system for programme production
5 Operation modes General 5.1 IEC 60958-1 specifies single- and two-channel operation modes. This document introduces several new operation modes based on the same interface format of IEC 60958-1 without the pre-emphasis function defined in IEC 60958-3. Channel status information identifies these modes in operation. This document shares the information with IEC 60958-1 and IEC 60958-3 and specifies new usages. 5.2 Multichannel linear PCM operation mode In multichannel linear PCM operation mode, the samples taken from multichannel linear PCM are transmitted by time multiplexing in consecutive sub-frames. A multichannel group is composed of several multichannel by consecutive frames. The number of multichannels included in the group is identified by the multichannel count of channel status bits 44 to 47. The group starts with preamble “B” and repeats itself with no break in the block and without un-grouped frames. The group is divided into one or two multichannel subgroups by the multichannel configuration of channel status bits 49 to 60 and the multichannel map of channel status bits 64 to 165. The subgroup is composed of some specific multichannels by consecutive sub-frames. Each multichannel within the multichannel subgroup B is re-numbered according to the multichannel number of channel status bits 64 to 165. Each channel carries consecutive audio sample words.3 Terms and definitions For the purposes of this document, the following terms and definitions 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 one-bit audio one-bit length audio data stream Note 1 to entry: A one-bit audio data stream can be directly played back through the analogue low-pass filter bit by bit (MSB first). 3.2 high-precision multi-bit linear audio linear PCM audio data longer than 25 bits length per sample Note 1 to entry: This document supports 32- and 64-bit lengths. 3.3 sampling frequency frequency of the samples representing an audio signal. Note 1 to entry: When more than one signal is transmitted through the same interface, the sampling frequencies are identical. [SOURCE: IEC 60958-1:20—, 3.1] 3.4 audio sample word value of a digital audio sample Note 1 to entry: Representation is linear in 2’s complement binary form. Note 2 to entry: Positive numbers correspond to positive analogue voltages at the input of the analogue-to-digital converter (ADC). [SOURCE: IEC 60958-1: 20—, 3.2] 3.5 channel status data carrying, in a fixed format, information associated with each main data field channel, which is decodable by any interface user. Note 1 to entry: IEC 60958-3 specifies the mode 0 channel status format for digital audio equipment for consumer use. EXAMPLE 1 Length of audio sample words. EXAMPLE 2 Sampling frequency. [SOURCE: IEC 60958-1:20—, 3.5, modified – Modification of the Note to entry, and addition of two examples.] 3.6 preamble specific patterns used for synchronization.