Audio Engine Handle. More...

Detailed Description

Audio Engine Handle.

This class allows for higher level access to an audio engine. If you're using a SOM like the DaisySeed or DaisyPatchSM (or any board that includes one of those objects) then the intialization is already taken care of. If you're setting up your own custom hardware, or need to make changes you will have to take the following steps:

Create and Initialize an SaiHandle or two depending on your requirements
Initialize the Audio Handle with the desired settings and the Initialized SaiHandle
If the connected codec requires special configuration or initialization, do so
Write a callback method using either the AudioCallback or the InterleavingAudioCallback format
Start the Audio using one of the StartAudio function

#include <audio.h>

Classes
struct	Config

Public Types
enum class	Result { OK , ERR }

typedef const float const	InputBuffer

typedef float **	OutputBuffer

typedef void(*	AudioCallback) (InputBuffer in, OutputBuffer out, size_t size)

typedef const float *	InterleavingInputBuffer

typedef float *	InterleavingOutputBuffer

typedef void(*	InterleavingAudioCallback) (InterleavingInputBuffer in, InterleavingOutputBuffer out, size_t size)

Public Member Functions
	AudioHandle ()

	~AudioHandle ()

	AudioHandle (const AudioHandle &other)=default

AudioHandle &	operator= (const AudioHandle &other)=default

Result	Init (const Config &config, SaiHandle sai)

Result	Init (const Config &config, SaiHandle sai1, SaiHandle sai2)

Result	DeInit ()

const Config &	GetConfig () const

size_t	GetChannels () const

float	GetSampleRate ()

Result	SetSampleRate (SaiHandle::Config::SampleRate samplerate)

Result	SetBlockSize (size_t size)

Result	SetPostGain (float val)

Result	SetOutputCompensation (float val)

Result	Start (AudioCallback callback)

Result	Start (InterleavingAudioCallback callback)

Result	Stop ()

Result	ChangeCallback (AudioCallback callback)

Result	ChangeCallback (InterleavingAudioCallback callback)

Member Typedef Documentation

◆ AudioCallback

typedef void(* daisy::AudioHandle::AudioCallback) (InputBuffer in, OutputBuffer out, size_t size)

Type for a Non-Interleaving audio callback Non-Interleaving audio callbacks in daisy will be of this type

◆ InputBuffer

typedef const float* const* daisy::AudioHandle::InputBuffer

Non-Interleaving input buffer Buffer arranged by float[chn][sample] const so that the user can't modify the input

◆ InterleavingAudioCallback

typedef void(* daisy::AudioHandle::InterleavingAudioCallback) (InterleavingInputBuffer in, InterleavingOutputBuffer out, size_t size)

Interleaving Audio Callback Interleaving audio callbacks in daisy must be of this type

◆ InterleavingInputBuffer

typedef const float* daisy::AudioHandle::InterleavingInputBuffer

Interleaving Input buffer audio is prepared as { L0, R0, L1, R1, . . . LN, RN }] this is const, as the user shouldn't modify it

◆ InterleavingOutputBuffer

typedef float* daisy::AudioHandle::InterleavingOutputBuffer

Interleaving Output buffer audio is prepared as { L0, R0, L1, R1, . . . LN, RN }

◆ OutputBuffer

typedef float** daisy::AudioHandle::OutputBuffer

Non-Interleaving output buffer Arranged by float[chn][sample]

Member Enumeration Documentation

◆ Result

enum class daisy::AudioHandle::Result

strong

Enumerator
OK
ERR

Constructor & Destructor Documentation

◆ AudioHandle() [1/2]

daisy::AudioHandle::AudioHandle ( )

inline

◆ ~AudioHandle()

daisy::AudioHandle::~AudioHandle ( )

inline

◆ AudioHandle() [2/2]

daisy::AudioHandle::AudioHandle ( const AudioHandle & other )

default

Member Function Documentation

◆ ChangeCallback() [1/2]

Result daisy::AudioHandle::ChangeCallback ( AudioCallback callback )

Immediatley changes the audio callback to the non-interleaving callback passed in.

◆ ChangeCallback() [2/2]

Result daisy::AudioHandle::ChangeCallback ( InterleavingAudioCallback callback )

Immediatley changes the audio callback to the interleaving callback passed in.

◆ DeInit()

Result daisy::AudioHandle::DeInit ( )

Stops and deinitializes audio.

◆ GetChannels()

size_t daisy::AudioHandle::GetChannels ( ) const

Returns the number of channels of audio.

When using a single SAI this returns 2, when using two SAI it returns 4 If no SAI is initialized this returns 0

Eventually when we add non-standard I2S for each SAI this will be work differently

◆ GetConfig()

const Config & daisy::AudioHandle::GetConfig ( ) const

Returns the Global Configuration struct for the Audio

◆ GetSampleRate()

float daisy::AudioHandle::GetSampleRate ( )

Returns the Samplerate as a float

◆ Init() [1/2]

Result daisy::AudioHandle::Init	(	const Config &	config,
		SaiHandle	sai
	)

Initializes audio to run using a single SAI configured in Stereo I2S mode.

◆ Init() [2/2]

Result daisy::AudioHandle::Init	(	const Config &	config,
		SaiHandle	sai1,
		SaiHandle	sai2
	)

Initializes audio to run using two SAI, each configured in Stereo I2S mode.

◆ operator=()

AudioHandle & daisy::AudioHandle::operator= ( const AudioHandle & other )

default

◆ SetBlockSize()

Result daisy::AudioHandle::SetBlockSize ( size_t size )

Sets the block size after initialization, and updates the internal configuration struct. Get BlockSize and other details via the GetConfig

◆ SetOutputCompensation()

Result daisy::AudioHandle::SetOutputCompensation ( float val )

Sets an additional amount of gain compensation to perform at the end of the callback Useful if the hardware input/output levels are not equal.

Parameters

val	To calcuate the value, measure the input signal, then measure the output signal (with this set to default value of 1.0). Then calculate val as: val = 1 / (vout / vin);

◆ SetPostGain()

Result daisy::AudioHandle::SetPostGain ( float val )

Sets the amount of gain adjustment to perform before and after callback. useful if the hardware has additional headroom, and the nominal value shouldn't be 1.0

Parameters

val	Gain adjustment amount. The hardware will clip at the reciprical of this value.

◆ SetSampleRate()

Result daisy::AudioHandle::SetSampleRate ( SaiHandle::Config::SampleRate samplerate )

Sets the samplerate, and reinitializes the sai as needed.

◆ Start() [1/2]

Result daisy::AudioHandle::Start ( AudioCallback callback )

Starts the Audio using the non-interleaving callback.

◆ Start() [2/2]

Result daisy::AudioHandle::Start ( InterleavingAudioCallback callback )

Starts the Audio using the interleaving callback. For now only two channels are supported via this method.

◆ Stop()

Result daisy::AudioHandle::Stop ( )

Stop the Audio

The documentation for this class was generated from the following file:

src/hid/audio.h