Audacity 3.2.0
Classes | Macros | Functions
AudioIO.cpp File Reference
#include "AudioIO.h"
#include "AudioIOExt.h"
#include "AudioIOListener.h"
#include "float_cast.h"
#include "DeviceManager.h"
#include <cfloat>
#include <math.h>
#include <stdlib.h>
#include <algorithm>
#include <numeric>
#include <optional>
#include <malloc.h>
#include "portaudio.h"
#include <wx/wxcrtvararg.h>
#include <wx/log.h>
#include <wx/time.h>
#include <wx/debug.h>
#include <wx/power.h>
#include "Meter.h"
#include "Mix.h"
#include "Resample.h"
#include "RingBuffer.h"
#include "Decibels.h"
#include "Prefs.h"
#include "Project.h"
#include "TransactionScope.h"
#include "RealtimeEffectManager.h"
#include "QualitySettings.h"
#include "SampleTrack.h"
#include "BasicUI.h"
#include "Gain.h"
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struct  AudioIoCallback::TransportState


#define MAX(a, b)   ((a) > (b) ? (a) : (b))


int audacityAudioCallback (const void *inputBuffer, void *outputBuffer, unsigned long framesPerBuffer, const PaStreamCallbackTimeInfo *timeInfo, PaStreamCallbackFlags statusFlags, void *userData)
static PaSampleFormat AudacityToPortAudioSampleFormat (sampleFormat format)
static void DoSoftwarePlaythrough (constSamplePtr inputBuffer, sampleFormat inputFormat, unsigned inputChannels, float *outputBuffer, unsigned long len)
void ClampBuffer (float *pBuffer, unsigned long len)

Macro Definition Documentation


#define MAX (   a,
)    ((a) > (b) ? (a) : (b))

Definition at line 2402 of file AudioIO.cpp.

Function Documentation

◆ audacityAudioCallback()

int audacityAudioCallback ( const void *  inputBuffer,
void *  outputBuffer,
unsigned long  framesPerBuffer,
const PaStreamCallbackTimeInfo *  timeInfo,
PaStreamCallbackFlags  statusFlags,
void *  userData 

brief The function which is called from PortAudio's callback thread context to collect and deliver audio for / from the sound device.

This covers recording, playback, and doing both simultaneously. It is also invoked to do monitoring and software playthrough. Note that dealing with the two buffers needs some care to ensure that the right things happen for all possible cases.

inputBufferBuffer of length framesPerBuffer containing samples from the sound card, or null if not capturing audio. Note that the data type will depend on the format of audio data that was chosen when the stream was created (so could be floats or various integers)
outputBufferUninitialised buffer of length framesPerBuffer which will be sent to the sound card after the callback, or null if not playing audio back.
framesPerBufferThe length of the playback and recording buffers
PaStreamCallbackTimeInfoPointer to PortAudio time information structure, which tells us how long we have been playing / recording
statusFlagsPortAudio stream status flags
userDatapointer to user-defined data structure. Provided for flexibility by PortAudio, but not used by Audacity - the data is stored in the AudioIO class instead.

Definition at line 2423 of file AudioIO.cpp.

2428 auto gAudioIO = AudioIO::Get();
2429 return gAudioIO->AudioCallback(
2430 static_cast<constSamplePtr>(inputBuffer),
2431 static_cast<float*>(outputBuffer), framesPerBuffer,
2432 timeInfo, statusFlags, userData);
const char * constSamplePtr
Definition: SampleFormat.h:56
static AudioIO * Get()
Definition: AudioIO.cpp:147

References AudioIO::Get().

Referenced by AudioIO::StartPortAudioStream().

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◆ AudacityToPortAudioSampleFormat()

static PaSampleFormat AudacityToPortAudioSampleFormat ( sampleFormat  format)

Definition at line 480 of file AudioIO.cpp.

482 switch(format) {
483 case int16Sample:
484 return paInt16;
485 case int24Sample:
486 return paInt24;
487 case floatSample:
488 default:
489 return paFloat32;
490 }
int format
Definition: ExportPCM.cpp:53
constexpr sampleFormat int16Sample
Definition: SampleFormat.h:41
constexpr sampleFormat floatSample
Definition: SampleFormat.h:43
constexpr sampleFormat int24Sample
Definition: SampleFormat.h:42

References floatSample, format, int16Sample, and int24Sample.

Referenced by AudioIO::StartPortAudioStream().

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◆ ClampBuffer()

void ClampBuffer ( float *  pBuffer,
unsigned long  len 

Definition at line 2512 of file AudioIO.cpp.

2512 {
2513 for(unsigned i = 0; i < len; i++)
2514 pBuffer[i] = std::clamp(pBuffer[i], -1.0f, 1.0f);

Referenced by AudioIoCallback::FillOutputBuffers().

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◆ DoSoftwarePlaythrough()

static void DoSoftwarePlaythrough ( constSamplePtr  inputBuffer,
sampleFormat  inputFormat,
unsigned  inputChannels,
float *  outputBuffer,
unsigned long  len 

Definition at line 2404 of file AudioIO.cpp.

2410 for (unsigned int i=0; i < inputChannels; i++) {
2411 auto inputPtr = inputBuffer + (i * SAMPLE_SIZE(inputFormat));
2413 SamplesToFloats(inputPtr, inputFormat,
2414 outputBuffer + i, len, inputChannels, 2);
2415 }
2417 // One mono input channel goes to both output channels...
2418 if (inputChannels == 1)
2419 for (int i=0; i < len; i++)
2420 outputBuffer[2*i + 1] = outputBuffer[2*i];
void SamplesToFloats(constSamplePtr src, sampleFormat srcFormat, float *dst, size_t len, size_t srcStride, size_t dstStride)
Copy samples from any format into the widest format, which is 32 bit float, with no dithering.
#define SAMPLE_SIZE(SampleFormat)
Definition: SampleFormat.h:50

References SAMPLE_SIZE, and SamplesToFloats().

Referenced by AudioIoCallback::DoPlaythrough().

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