UsacConfig/UsacDecoderConfig/UsacExtElementConfig
This element configuration can be used for configuring any kind of existing or future extensions to the codec
usacExtElementConfigLength: Signals the length of the extension configuration in bytes
usacExtElementDefaultLengthPresent: signals whether a usacExtElementDefaultLength is conveyed in the UsacExtElementConfig()
usacExtElementPayloadFrag: indicates whether the payload of this extension element may be fragmented and send as several segments in consecutive USAC frames
AudioPreRoll usacExtElementConfigLength is 1 but only 0 is allowed
AudioPreRoll usacExtElementDefaultLengthPresent is 1 but only 0 is allowed
AudioPreRoll usacExtElementPayloadFrag is 1 but only 0 is allowed
AudioPreRoll is present in position (value) but only presence in position 0 is allowed