audioPackFormat (Matrix)

The audioPackFormat with typeDefinition 'Matrix' needs extra sub-elements to allow the definition of encoding (e.g. Left/Right to Mid/Side), decoding (e.g. Mid/Side to Left/Right) and direct (e.g. Lo/Ro) matrices.

The matrix can either be an encoding, a decoding or a direct matrix. An encoding matrix converts an input pack of any type (though “DirectSpeakers” would be the most likely to be used) into a matrix-encoded pack. A decoding matrix takes matrix-encoded pack and converts into a channel-based output pack. Related encoding and decoding matrices can be cross-referenced.

For example, Stereo to Mid/Side would be an encoding matrix, and Mid/Side to Stereo would be a decoding matrix.

The diagram below how encoder and decoder matrix audioPackFormats relate to each other, as well in the input and output audioPackFormats and audioChannelFormats.

The diagram below shows how a direct matrix audioPackFormat relates to input and output audioPackFormats and audioChannelFormats.

Attributes

There are no additional attributes defined for the audioPackFormat with typeDefinition 'Matrix'. See Common Attributes for the list of common ones.

Sub-elements

In addition to the common sub-elements the following sub-elements are defined for the audioPackFormat with typeDefinition 'Matrix'.

Even though it is defined as a common sub-element, the absoluteDistance sub-element is unlikely to be used in the 'Matrix' mode.

Sub-element	Description	Example	Quantity
audioChannelFormatIDRef	Reference to an audioChannelFormat	AC_00021001	0...*
audioPackFormatIDRef	Reference to an audioPackFormat	AP_00021002	0...*
absoluteDistance	Absolute distance in metres	4.5	0 or 1
encodePackFormatIDRef	Reference to an encoding matrix audioPackFormat from a decoding matrix.	AP_00020001	0…*
decodePackFormatIDRef	Reference to a decoding matrix audioPackFormat from an encoding matrix.	AP_00020101	0 …*
inputPackFormatIDRef	Reference to a channel-based (DirectSpeakers) input audioPackFormat.	AP_00010002	0 or 1
outputPackFormatIDRef	Reference to a channel-based (DirectSpeakers) matrix decoded audioPackFormat.	AP_00010002	0 or 1

The encoding matrix contains an inputPackFormatIDRef, which references a channel-based input pack. It can also contain a list of decodePackFormatIDRefs, which are references to corresponding decoding matrices.

The decoding matrix contains an outputPackFormatIDRef, which reference a channel-based output pack. It can also contain a list of encodePackFormatIDRefs, which are references to corresponding encoding matrices.

The direct matrix contains an inputPackFormatIDRef, which references a channel-based input pack and an outputPackFormatIDRef, which reference a channel-based output pack.

Example

<audioPackFormat audioPackFormatID="AP_00021001"
                 audioPackFormatName="PackMat1_Encode"
                 typeLabel="0002" typeDefinition="Matrix">
  <audioChannelFormatIDRef>AC_00021001</audioChannelFormatIDRef>
  <audioChannelFormatIDRef>AC_00021002</audioChannelFormatIDRef>
  <decodePackFormatIDRef>AP_00021101</decodePackFormatIDRef>
  <inputPackFormatIDRef>AP_00010002</inputPackFormatIDRef>
</audioPackFormat>