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BALibrary_parasitstudio/src/LibBasicFunctions.h

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/**************************************************************************//**
* @file
* @author Steve Lascos
* @company Blackaddr Audio
*
* LibBasicFunctions is a collection of helpful functions and classes that make
* it easier to perform common tasks in Audio applications.
*
* @copyright This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.*
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*****************************************************************************/
#include <cstddef>
#include <new>
#include <atomic>
#include <arm_math.h>
#include "Arduino.h"
#include "Audio.h"
#include "BATypes.h"
#include "LibMemoryManagement.h"
#ifndef __BALIBRARY_LIBBASICFUNCTIONS_H
#define __BALIBRARY_LIBBASICFUNCTIONS_H
namespace BALibrary {
/**************************************************************************//**
* QueuePosition is used for storing the index (in an array of queues) and the
* offset within an audio_block_t data buffer. Useful for dealing with large
* windows of audio spread across multiple audio data blocks.
*****************************************************************************/
struct QueuePosition {
int offset; ///< offset in samples within an audio_block_t data buffer
int index; ///< index in an array of audio data blocks
};
/// Calculate the exact sample position in an array of audio blocks that corresponds
/// to a particular offset given as time.
/// @param milliseconds length of the interval in milliseconds
/// @returns a struct containing the index and offset
QueuePosition calcQueuePosition(float milliseconds);
/// Calculate the exact sample position in an array of audio blocks that corresponds
/// to a particular offset given as a number of samples
/// @param milliseconds length of the interval in milliseconds
/// @returns a struct containing the index and offset
QueuePosition calcQueuePosition(size_t numSamples);
/// Calculate the number of audio samples (rounded up) that correspond to a
/// given length of time.
/// @param milliseconds length of the interval in milliseconds
/// @returns the number of corresonding audio samples.
size_t calcAudioSamples(float milliseconds);
/// Calculate a length of time in milliseconds from the number of audio samples.
/// @param numSamples Number of audio samples to convert to time
/// @return the equivalent time in milliseconds.
float calcAudioTimeMs(size_t numSamples);
/// Calculate the number of audio samples (usually an offset) from
/// a queue position.
/// @param position specifies the index and offset within a queue
/// @returns the number of samples from the start of the queue array to the
/// specified position.
size_t calcOffset(QueuePosition position);
/// Clear the contents of an audio block to zero
/// @param block pointer to the audio block to clear
void clearAudioBlock(audio_block_t *block);
/// Perform an alpha blend between to audio blocks. Performs <br>
/// out = dry*(1-mix) + wet*(mix)
/// @param out pointer to the destination audio block
/// @param dry pointer to the dry audio
/// @param wet pointer to the wet audio
/// @param mix float between 0.0 and 1.0.
void alphaBlend(audio_block_t *out, audio_block_t *dry, audio_block_t* wet, float mix);
/// Applies a gain to the audio via fixed-point scaling accoring to <br>
/// out = int * (vol * 2^coeffShift)
/// @param out pointer to output audio block
/// @param in pointer to input audio block
/// @param vol volume cofficient between -1.0 and +1.0
/// @param coeffShift number of bits to shift the coefficient
void gainAdjust(audio_block_t *out, audio_block_t *in, float vol, int coeffShift = 0);
/// Combine two audio blocks through vector addition
/// out[n] = in0[n] + in1[n]
/// @param out pointer to output audio block
/// @param in0 pointer to first input audio block to combine
/// @param in1 pointer to second input audio block to combine
void combine(audio_block_t *out, audio_block_t *in0, audio_block_t *in1);
template <class T>
class RingBuffer; // forward declare so AudioDelay can use it.
/**************************************************************************//**
* Audio delays are a very common function in audio processing. In addition to
* being used for simply create a delay effect, it can also be used for buffering
* a sliding window in time of audio samples. This is useful when combining
* several audio_block_t data buffers together to form one large buffer for
* FFTs, etc.
* @details The buffer works like a queue. You add new audio_block_t when available,
* and the class will return an old buffer when it is to be discarded from the queue.<br>
* Note that using INTERNAL memory means the class will only store a queue
* of pointers to audio_block_t buffers, since the Teensy Audio uses a shared memory
* approach. When using EXTERNAL memory, data is actually copyied to/from an external
* SRAM device.
*****************************************************************************/
constexpr size_t AUDIO_BLOCK_SIZE = sizeof(int16_t)*AUDIO_BLOCK_SAMPLES;
class AudioDelay {
public:
AudioDelay() = delete;
/// Construct an audio buffer using INTERNAL memory by specifying the max number
/// of audio samples you will want.
/// @param maxSamples equal or greater than your longest delay requirement
AudioDelay(size_t maxSamples);
/// Construct an audio buffer using INTERNAL memory by specifying the max amount of
/// time you will want available in the buffer.
/// @param maxDelayTimeMs max length of time you want in the buffer specified in milliseconds
AudioDelay(float maxDelayTimeMs);
/// Construct an audio buffer using a slot configured with the BALibrary::ExternalSramManager
/// @param slot a pointer to the slot representing the memory you wish to use for the buffer.
AudioDelay(ExtMemSlot *slot);
~AudioDelay();
/// Add a new audio block into the buffer. When the buffer is filled,
/// adding a new block will push out the oldest once which is returned.
/// @param blockIn pointer to the most recent block of audio
/// @returns the buffer to be discarded, or nullptr if not filled (INTERNAL), or
/// not applicable (EXTERNAL).
audio_block_t *addBlock(audio_block_t *blockIn);
/// When using INTERNAL memory, returns the pointer for the specified index into buffer.
/// @details, the most recent block is 0, 2nd most recent is 1, ..., etc.
/// @param index the specifies how many buffers older than the current to retrieve
/// @returns a pointer to the requested audio_block_t
audio_block_t *getBlock(size_t index);
/// Returns the max possible delay samples. For INTERNAL memory, the delay can be equal to
/// the full maxValue specified. For EXTERNAL memory, the max delay is actually one audio
/// block less then the full size to prevent wrapping.
/// @returns the maximum delay offset in units of samples.
size_t getMaxDelaySamples();
/// Retrieve an audio block (or samples) from the buffer into a destination block
/// @details when using INTERNAL memory, only supported size is AUDIO_BLOCK_SAMPLES. When using
/// EXTERNAL, a size smaller than AUDIO_BLOCK_SAMPLES can be requested.
/// @param dest pointer to the target audio block to write the samples to.
/// @param offsetSamples data will start being transferred offset samples from the start of the audio buffer
/// @param numSamples default value is AUDIO_BLOCK_SAMPLES, so typically you don't have to specify this parameter.
/// @returns true on success, false on error.
bool getSamples(audio_block_t *dest, size_t offsetSamples, size_t numSamples = AUDIO_BLOCK_SAMPLES);
/// Retrieve an audio block (or samples) from the buffer into a destination sample array
/// @details when using INTERNAL memory, only supported size is AUDIO_BLOCK_SAMPLES. When using
/// EXTERNAL, a size smaller than AUDIO_BLOCK_SAMPLES can be requested.
/// @param dest pointer to the target sample array to write the samples to.
/// @param offsetSamples data will start being transferred offset samples from the start of the audio buffer
/// @param numSamples number of samples to transfer
/// @returns true on success, false on error.
bool getSamples(int16_t *dest, size_t offsetSamples, size_t numSamples);
/// Provides linearly interpolated samples between discrete samples in the sample buffer. The SOURCE buffer MUST BE OVERSIZED
/// to numSamples+1. This is because the last output sample is interpolated from between NUM_SAMPLES and NUM_SAMPLES+1.
/// @details this function is typically not used with audio blocks directly since you need AUDIO_BLOCK_SAMPLES+1 as the source size
/// even though output size is still only AUDIO_BLOCK_SAMPLES. Manually create an oversized buffer and fill it with AUDIO_BLOCK_SAMPLES+1.
/// e.g. 129 instead of 128 samples. The destBuffer does not need to be oversized.
/// @param extendedSourceBuffer A source array that contains one more input sample than output samples needed.
/// @param dest pointer to the target sample array to write the samples to.
/// @param fraction a value between 0.0f and 1.0f that sets the interpolation point between the discrete samples.
/// @param numSamples number of samples to transfer
/// @returns true on success, false on error.
bool interpolateDelay(int16_t *extendedSourceBuffer, int16_t *destBuffer, float fraction, size_t numSamples = AUDIO_BLOCK_SAMPLES);
/// When using EXTERNAL memory, this function can return a pointer to the underlying ExtMemSlot object associated
/// with the buffer.
/// @returns pointer to the underlying ExtMemSlot.
ExtMemSlot *getSlot() const { return m_slot; }
/// Ween using INTERNAL memory, thsi function can return a pointer to the underlying RingBuffer that contains
/// audio_block_t * pointers.
/// @returns pointer to the underlying RingBuffer
RingBuffer<audio_block_t*> *getRingBuffer() const { return m_ringBuffer; }
private:
/// enumerates whether the underlying memory buffer uses INTERNAL or EXTERNAL memory
enum class MemType : unsigned {
MEM_INTERNAL = 0, ///< internal audio_block_t from the Teensy Audio Library is used
MEM_EXTERNAL ///< external SPI based ram is used
};
MemType m_type; ///< when 0, INTERNAL memory, when 1, external MEMORY.
RingBuffer<audio_block_t *> *m_ringBuffer = nullptr; ///< When using INTERNAL memory, a RingBuffer will be created.
ExtMemSlot *m_slot = nullptr; ///< When using EXTERNAL memory, an ExtMemSlot must be provided.
size_t m_maxDelaySamples = 0; ///< stores the number of audio samples in the AudioDelay.
bool m_getSamples(int16_t *dest, size_t offsetSamples, size_t numSamples); ///< operates directly on int16_y buffers
};
/**************************************************************************//**
* IIR BiQuad Filter - Direct Form I <br>
* y[n] = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]<br>
* Some design tools (like Matlab assume the feedback coefficients 'a' are negated. You
* may have to negate your 'a' coefficients.
* @details Note that the ARM CMSIS-DSP library requires an extra zero between first
* and second 'b' coefficients. E.g. <br>
* {b10, 0, b11, b12, a11, a12, b20, 0, b21, b22, a21, a22, ...}
*****************************************************************************/
class IirBiQuadFilter {
public:
IirBiQuadFilter() = delete;
/// Construct a Biquad filter with specified number of stages, coefficients and scaling.
/// @details See CMSIS-DSP documentation for more details
/// @param numStages number of biquad stages. Each stage has 5 coefficients.
/// @param coeffs pointer to an array of Q31 fixed-point coefficients (range -1 to +0.999...)
/// @param coeffShift coeffs are multiplied by 2^coeffShift to support coefficient range scaling
IirBiQuadFilter(unsigned numStages, const int32_t *coeffs, int coeffShift = 0);
virtual ~IirBiQuadFilter();
/// Reconfigure the filter coefficients.
/// @details See CMSIS-DSP documentation for more details
/// @param numStages number of biquad stages. Each stage has 5 coefficients.
/// @param coeffs pointer to an array of Q31 fixed-point coefficients (range -1 to +0.999...)
/// @param coeffShift coeffs are multiplied by 2^coeffShift to support coefficient range scaling
void changeFilterCoeffs(unsigned numStages, const int32_t *coeffs, int coeffShift = 0);
/// Process the data using the configured IIR filter
/// @details output and input can be the same pointer if in-place modification is desired
/// @param output pointer to where the output results will be written
/// @param input pointer to where the input data will be read from
/// @param numSampmles number of samples to process
bool process(int16_t *output, int16_t *input, size_t numSamples);
private:
const unsigned NUM_STAGES;
int32_t *m_coeffs = nullptr;
// ARM DSP Math library filter instance
arm_biquad_casd_df1_inst_q31 m_iirCfg;
int32_t *m_state = nullptr;
};
/**************************************************************************//**
* A High-precision version of IirBiQuadFilter often necessary for complex, multistage
* filters. This class uses CMSIS-DSP biquads with 64-bit internal precision instead
* of 32-bit.
*****************************************************************************/
class IirBiQuadFilterHQ {
public:
IirBiQuadFilterHQ() = delete;
/// Construct a Biquad filter with specified number of stages, coefficients and scaling.
/// @details See CMSIS-DSP documentation for more details
/// @param numStages number of biquad stages. Each stage has 5 coefficients.
/// @param coeffs pointer to an array of Q31 fixed-point coefficients (range -1 to +0.999...)
/// @param coeffShift coeffs are multiplied by 2^coeffShift to support coefficient range scaling
IirBiQuadFilterHQ(unsigned maxNumStages, const int32_t *coeffs, int coeffShift = 0);
virtual ~IirBiQuadFilterHQ();
/// Reconfigure the filter coefficients.
/// @details See CMSIS-DSP documentation for more details
/// @param numStages number of biquad stages. Each stage has 5 coefficients.
/// @param coeffs pointer to an array of Q31 fixed-point coefficients (range -1 to +0.999...)
/// @param coeffShift coeffs are multiplied by 2^coeffShift to support coefficient range scaling
void changeFilterCoeffs(unsigned numStages, const int32_t *coeffs, int coeffShift = 0);
/// Process the data using the configured IIR filter
/// @details output and input can be the same pointer if in-place modification is desired
/// @param output poinvoid combine(audio_block_t *out, audio_block_t *in0, audio_block_t *in1)ter to where the output results will be written
/// @param input pointer to where the input data will be read from
/// @param numSampmles number of samples to process
bool process(int16_t *output, int16_t *input, size_t numSamples);
private:
const unsigned NUM_STAGES;
int32_t *m_coeffs = nullptr;
// ARM DSP Math library filter instance
arm_biquad_cas_df1_32x64_ins_q31 m_iirCfg;
int64_t *m_state = nullptr;
};
/**************************************************************************//**
* A single-precision floating-point biquad using CMSIS-DSP hardware instructions.
* @details Use this when IirBiQuadFilterHQ is insufficient, since that version
* is still faster with 64-bit fixed-point arithmetic.
*****************************************************************************/
class IirBiQuadFilterFloat {
public:
IirBiQuadFilterFloat() = delete;
/// Construct a Biquad filter with specified number of stages and coefficients
/// @details See CMSIS-DSP documentation for more details
/// @param numStages number of biquad stages. Each stage has 5 coefficients.
/// @param coeffs pointer to an array of single-precision floating-point coefficients
IirBiQuadFilterFloat(unsigned maxNumStages, const float *coeffs);
virtual ~IirBiQuadFilterFloat();
/// Reconfigure the filter coefficients.
/// @details See CMSIS-DSP documentation for more details
/// @param numStages number of biquad stages. Each stage has 5 coefficients.
/// @param coeffs pointer to an array of single-precision floating-point coefficients
void changeFilterCoeffs(unsigned numStages, const float *coeffs);
/// Process the data using the configured IIR filter
/// @details output and input can be the same pointer if in-place modification is desired
/// @param output pointer to where the output results will be written
/// @param input pointer to where the input data will be read from
/// @param numberSampmles number of samples to process
bool process(float *output, float *input, size_t numSamples);
private:
const unsigned NUM_STAGES;
float *m_coeffs = nullptr;
// ARM DSP Math library filter instance
arm_biquad_cascade_df2T_instance_f32 m_iirCfg;
float *m_state = nullptr;
};
} // namespace BALibrary
namespace BALibrary {
/**************************************************************************//**
* The class will automate a parameter using a trigger from a start value to an
* end value, using either a preprogrammed function or a user-provided LUT.
*****************************************************************************/
template <typename T>
class ParameterAutomation
{
public:
enum class Function : unsigned {
NOT_CONFIGURED = 0, ///< Initial, unconfigured stage
HOLD, ///< f(x) = constant
LINEAR, ///< f(x) = x
EXPONENTIAL, ///< f(x) = exp(-k*x)
LOGARITHMIC, ///< f(x) =
PARABOLIC, ///< f(x) = x^2
LOOKUP_TABLE ///< f(x) = lut(x)
};
ParameterAutomation();
ParameterAutomation(T startValue, T endValue, size_t durationSamples, Function function = Function::LINEAR);
ParameterAutomation(T startValue, T endValue, float durationMilliseconds, Function function = Function::LINEAR);
virtual ~ParameterAutomation();
/// set the start and end values for the automation
/// @param function select which automation curve (function) to use
/// @param startValue after reset, parameter automation start from this value
/// @param endValue after the automation duration, paramter will finish at this value
/// @param durationSamples number of samples to transition from startValue to endValue
void reconfigure(T startValue, T endValue, size_t durationSamples, Function function = Function::LINEAR);
void reconfigure(T startValue, T endValue, float durationMilliseconds, Function function = Function::LINEAR);
/// Start the automation from startValue
void trigger();
/// Retrieve the next calculated automation value
/// @returns the calculated parameter value of templated type T
T getNextValue();
bool isFinished() { return !m_running; }
private:
Function m_function;
T m_startValue;
T m_endValue;
bool m_running = false;
float m_currentValueX; ///< the current value of x in f(x)
size_t m_duration;
//float m_coeffs[3]; ///< some general coefficient storage
float m_slopeX;
float m_scaleY;
bool m_positiveSlope = true;
};
// TODO: initialize with const number of sequences with null type that automatically skips
// then register each new sequence.
constexpr int MAX_PARAMETER_SEQUENCES = 32;
template <typename T>
class ParameterAutomationSequence
{
public:
ParameterAutomationSequence() = delete;
ParameterAutomationSequence(int numStages);
virtual ~ParameterAutomationSequence();
void setupParameter(int index, T startValue, T endValue, size_t durationSamples, typename ParameterAutomation<T>::Function function);
void setupParameter(int index, T startValue, T endValue, float durationMilliseconds, typename ParameterAutomation<T>::Function function);
/// Trigger a the automation sequence until numStages is reached or a Function is ParameterAutomation<T>::Function::NOT_CONFIGURED
void trigger();
T getNextValue();
bool isFinished();
private:
ParameterAutomation<T> *m_paramArray[MAX_PARAMETER_SEQUENCES];
int m_currentIndex = 0;
int m_numStages = 0;
bool m_running = false;
};
/// Supported LFO waveforms
enum class Waveform : unsigned {
SINE, ///< sinewave
TRIANGLE, ///< triangle wave
SQUARE, ///< square wave
SAWTOOTH, ///< sawtooth wave
RANDOM, ///< a non-repeating random waveform
NUM_WAVEFORMS, ///< the number of defined waveforms
};
/**************************************************************************//**
* The LFO is commonly used on modulation effects where some parameter (delay,
* volume, etc.) is modulated via waveform at a frequency below 20 Hz. Waveforms
* vary between -1.0f and +1.0f.
* @details this LFO is for operating on vectors of audio block samples.
*****************************************************************************/
template <class T>
class LowFrequencyOscillatorVector {
public:
/// Default constructor, uses SINE as default waveform
LowFrequencyOscillatorVector() {}
/// Specifies the desired waveform at construction time.
/// @param waveform specifies desired waveform
LowFrequencyOscillatorVector(Waveform waveform) : m_waveform(waveform) {};
/// Default destructor
~LowFrequencyOscillatorVector() {}
/// Change the waveform
/// @param waveform specifies desired waveform
void setWaveform(Waveform waveform) { m_waveform = waveform; }
/// Set the LFO rate in Hertz
/// @param frequencyHz the LFO frequency in Hertz
void setRateAudio(float frequencyHz);
/// Set the LFO rate as a fraction
/// @param ratio the radians/sample will be 2*pi*ratio
void setRateRatio(float ratio);
/// Get the next waveform value
/// @returns the next vector of phase values
T *getNextVector();
private:
void m_updatePhase(); ///< called internally when updating the phase vector
void m_initPhase(T radiansPerSample); ///< called internally to reset phase upon rate change
Waveform m_waveform = Waveform::SINE; ///< LFO waveform
T m_phaseVec[AUDIO_BLOCK_SAMPLES]; ///< the vector of next phase values
T m_radiansPerBlock = 0.0f; ///< stores the change in radians over one block of data
T m_outputVec[AUDIO_BLOCK_SAMPLES]; ///< stores the output LFO values
std::atomic_flag m_phaseLock = ATOMIC_FLAG_INIT; ///< used for thread-safety on m_phaseVec
const T PI_F = 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899; ///< 2*PI
const T TWO_PI_F = 2.0 * 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899; ///< 2*PI
const T PI_DIV2_F = 0.5 * 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899; ///< PI/2
const T THREE_PI_DIV2_F = 1.5 * 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899; ///< 3*PI/2
const T TRIANGE_POS_SLOPE = 2.0f/PI_F;
const T TRIANGE_NEG_SLOPE = -2.0f/PI_F;
const T SAWTOOTH_SLOPE = -1.0f/PI_F;
};
} // BALibrary
#endif /* __BALIBRARY_LIBBASICFUNCTIONS_H */