Table of Content

Audio Object Developers Guide

  1. Purpose of this Document
    1. Terms and Abbreviations
    2. Requirements
  2. Overview
    1. Audio Object Workflow
    2. Audio Object Class
  3. Audio Object Configuration
    1. Design Time Configuration
    2. Advanced Design Time Configuration
  4. Basic Features and APIs
    1. Constructor
    2. GetSize
    3. Init
    4. Calc
    5. TuneXTP
    6. Control
  5. Advanced Features and APIs
    1. Audio Object Additional Configuration
    2. Audio Object Sub Blocks
    3. Audio Object AO Switch Processing State
    4. Debug and Monitoring
    5. Background Method
  6. Audio object Examples
    1. Example 1 - AwxAudioObjExt.cpp
    2. Example 2 - AwxAudioObjExtToolbox.cpp
    3. Example 3 - AwxAudioObjExtMemRecs.cpp
    4. Example 4 - AwxAudioObjExt.h
    5. Example 5 - AwxAudioObjExtToolbox.h
    6. Example 6 - AwxAudioObjExtMemRecs.h
  7. General Guidelines
    1. Hardware Abstraction
    2. Hardware Abstraction for Header files
    3. Memory Enums
    4. Overlays
  8. Adding external audio object into AudioworX package
    1. Building External AO

Device Description File

  1. Terms and Abbreviations
  2. Purpose of this Document
  3. Root Element
  4. Node Elements
    1. Communication Parameters
    2. Identification of Target Device
  5. Virtual Device
  6. Objects
    1. Object
    2. Definition of a Table Object
    3. Definition of a Biquad Coefficients Object
  7. StateVariables
    1. Common
    2. NumericalSV
    3. EnumSV
    4. FilterTypeSV
    5. FloatArraySV
    6. Float16ArraySV
    7. FixedPoint16ArraySV
    8. StringSV
    9. FixedPointM_NArraySV
  8. TargetValue
    1. Common
    2. Target Value
    3. Block Target Value
  9. Templates
    1. StateVariables
  10. Revision History

Griffin Reference Projects User Guide

  1. Terms and Abbreviations
    1. Multi dll support for CAO
    2. Tuning Panel Compound Audio Object
  2. Purpose Of This Document
    1. Apply tuning to Compound Audio Object Template
    2. Testing New Post 2025

4.6.Control

Audio object control is carried out through CAudioObject→controlSet(). When a control message is received, it triggers the CAudioProcessing→setControlParameter(..) function, which in turn triggers the Control Input object control function, ControlIn→controlSet(..).

This then routes the control from the control input object to each object intended to receive the message through the audio object controlSet() method.

virtual int controlSet(int pin, float val);
where pin: is the input control pin index being updated 
val: the new value the control pin is being updated with

Objects that can be modified by control variables like volume, need to configure their object class control input and output values. These control I/Os are determined during the design of the audio object and can depend on the user configuration of the object during the signal design stage.

For example, a volume audio object will have multiple audio input and output channels. It will also have an input control that receives volume changes from the HU and an output control that relays those changes to other objects that depend on volume control.

These pins are a one to one connection between objects. If, at the output of the volume object, the volume control needs to be forwarded to multiple audio objects, the signal designer must add a control relay (ControlMath->splitter) object that can route those signals to multiple objects.

The implementation of this function is specific to the audio object. For example, a volume audio object control command will fade the volume value in the audio object starting from the old gain value and ending with the new gain value sent through the control command.

An object can also pass control to another object connected to its control output via the following CAudioObject→setControlOut(..) method. This method identifies which object should receive the output and passes the value to it.

/*!
*   Helper method for writing control to mapped outputs
*   param index - which of the object's control outputs we are writing to
*   param value - value we are writing out to the control output
*/
void setControlOut(int index, float value);

To be able to externally read the value of a control variable from an audio object, that data must be placed in the state memory of the object and described in the description file used by the GTT tool. This is done through the Device Description section.

Finally, objects that do not interact with any controls do not need to override this method.

controlSet MUST NOT write to another objects memory, if that memory is part of a larger block of memory that must be changes altogether. For example, controlSet must not write into memory containing filter coefficients because changing one coefficient alone is bound to break the filter behavior

Last updated on October 24, 2024
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