# typeDefinitions for audio types

## Description

In audioPackFormat and audioChannelFormat the type of audio needs to be defined. Currently there are five types of audio: DirectSpeakers, Matrix, Objects, HOA and Binaural. The types are defined by two attributes: typeDefinition, which is a human-readable name, and typeLabel, which is a numerical label for the type. The table below describes each of the five types.

typeDefinition typeLabel Description
DirectSpeakers 0001 For channel-based audio, where each channel feeds a speaker directly
Matrix 0002 For channel-based audio where channels are matrixed together, such as Mid-Side, Lt/Rt
Objects 0003 For object-based audio where channels represent audio objects (or parts of objects), so include positional information
HOA 0004 For scene-based audio where Ambisonics and HOA are used
Binaural 0005 For binaural audio, where playback is over headphones

It is not necessary to include both typeDefinition and typeLabel attributes in an audioPackFormat and audioChannelFormat definition, but at least one of them must be present.

## Example

This is how typeLabel and typeDefintion can be used in an audioPackFormat:

<audioPackFormat audioPackFormatID="AP_00031002"
audioPackFormatName="PackObj2"
typeLabel="0003" typeDefinition="Objects" importance="7">
<audioChannelFormatIDRef>AC_00031003</audioChannelFormatIDRef>
</audioPackFormat>