IEC 62574:2020 pdf free download – Audio, video and multimedia systems – General channel assignmentof multichannel audio
1 Scope
This document specifies the general channel assignment and the metadata for multichannelaudio formats. The general channel assignment as a This document,with its channel mappingand labelling content,provides the unified usage of channel assignments for source devices,digital audio interfaces and sink devices. This standard The general channel assignmentexcludes the specification of the exact position of each loudspeaker.The metadata has the exactposition of each loudspeaker; however，since the position of the loudspeaker is different invarious surround sound formats, the position information of the metadata is not standardized.ltis aimed at consumer applications, but; it is not targeted at theatrical environments. Up to 32 65labels for loudspeaker positions and 15 labels for loudspeakers on the display are ‘specified,which can be used for all current multichannel audio formats.The channel assignment conceptis room centric and listener centric.This general channel assignment specifies the position of theloudspeaker as seen from the listener.
5.1 General
Metadata carries information on the speaker configuration of the multichannel audio format andother necessary information to reproduce its audio signal properly.The scope of metadata doesnot include the information of the rendering and the broadcast. Ilf the manufacturer adds metadatato the rendered signal, it is possible to obtain correct channel information for post processing.For example, if the optional virtual surround system can obtain correct speaker information forthe rendered signal, correct compatibility is obtained (see Figure 7a). If there is accurate speakerposition information, the ideal reproduced sound can be rendered(see Figure 7b).
A.3.1General
The channel assignment specifies the channels of multichannel audio，the loudspeakerassignment is the loudspeaker position of its channels.
A.3.2The model
Figure A.1 shows the model, in lEC 62574:2011, of channel assignment spaces with the threelayers, and a listener is located in the centre of the bottom layer.The middle layer is located atthe vertical centre of the picture screen or alternatively at the same height as the height of alistener’s ear.
This model specifies the general channel assignments in these three layers,which are the toplayer, the middle layer and the bottom layer.Each layer specifies channels in its layer.
Figure A.2 shows the top layer with its channel assignments,Figure A.3 shows the middle layerwith its channel assignments and Figure A.4 shows the bottom layer with its channel assignmentsin lEC 62574:2011.
B.1 General
This annex is a comparison chart of loudspeaker positions between lEC and other multichannelaudio formats.The same channel name may not be in the same position depending on the multi-channel audio format. These tables help in understanding the compatibility of each multichannelaudio format.
There are many multichannel audio formats and there will be new formats.These formats havea specific channel assignment,such as a channel mapping and channel labels, but the basicchannel assignments are not so different from each other.These can be unified to one commonchannel assignment as the general channel assignment. This general channel assignmentprovides audio devices and digital audio interfaces with the usage of unified channel assignmentsfor any multichannel audio formats. This second edition provides consistency with variousstandards.The channel names have changed in this second edition; the differences are shownin Annex B. Since there are standards that refer to the first edition of this document (seeClause A.1)，IEC 62574:2011 (the first edition) is cited at length in Annex A. The first edition(IEC 62574:2011) and the second edition (this document) can be distinguished by the numberingof the channels.