120 lines
5.4 KiB
C++
120 lines
5.4 KiB
C++
//( { file_desc: "Cross platform audio device interface." kw:[audio rt] }
|
|
//
|
|
// This interface provides data declarations for platform dependent
|
|
// audio I/O functions. The implementation for the functions are
|
|
// in platform specific modules. See cmAudioPortOsx.c and cmAudioPortAlsa.c.
|
|
//
|
|
// ALSA Notes:
|
|
// Assign capture device to line or mic input:
|
|
// amixer -c 0 cset iface=MIXER,name='Input Source',index=0 Mic
|
|
// amixer -c 0 cset iface=MIXER,name='Input Source',index=0 Line
|
|
//
|
|
// -c 0 select the first card
|
|
// -iface=MIXER the cset is targetting the MIXER component
|
|
// -name='Input Source',index=0 the control to set is the first 'Input Source'
|
|
// Note that the 'Capture' control sets the input gain.
|
|
//
|
|
// See alsamixer for a GUI to accomplish the same thing.
|
|
//
|
|
//
|
|
//)
|
|
|
|
#ifndef cwAudioPort_H
|
|
#define cwAudioPort_H
|
|
|
|
namespace cw
|
|
{
|
|
namespace audio
|
|
{
|
|
namespace device
|
|
{
|
|
typedef float sample_t;
|
|
|
|
// audioPacket_t flags
|
|
enum
|
|
{
|
|
kInterleavedApFl = 0x01, // The audio samples are interleaved.
|
|
kFloatApFl = 0x02 // The audio samples are single precision floating point values.
|
|
};
|
|
|
|
// Audio packet record used by the audioPacket_t callback.
|
|
// Audio ports send and receive audio using this data structure.
|
|
typedef struct
|
|
{
|
|
unsigned devIdx; // device associated with packet
|
|
unsigned begChIdx; // first device channel
|
|
unsigned chCnt; // count of channels
|
|
unsigned audioFramesCnt; // samples per channel (see note below)
|
|
unsigned bitsPerSample; // bits per sample word
|
|
unsigned flags; // kInterleavedApFl | kFloatApFl
|
|
void* audioBytesPtr; // pointer to sample data
|
|
void* userCbPtr; // user defined argument passed in via deviceSetup()
|
|
time::spec_t timeStamp; // Packet time stamp.
|
|
} audioPacket_t;
|
|
|
|
|
|
// Audio port callback signature.
|
|
// inPktArray[inPktCnt] are full packets of audio coming from the ADC to the application.
|
|
// outPktArray[outPktCnt] are empty packets of audio which will be filled by the application
|
|
// and then sent to the DAC.
|
|
//
|
|
// The value of audioFrameCnt gives the number of samples per channel which are available
|
|
// in the packet data buffer 'audioBytesPtr'. The callback function may decrease this number in
|
|
// output packets if the number of samples available is less than the size of the buffer.
|
|
// It is the responsibility of the calling audio port to notice this change and pass the new,
|
|
// decreased number of samples to the hardware.
|
|
//
|
|
// In general it should be assmed that this call is made from a system thread which is not
|
|
// the same as the application thread.
|
|
// The usual thread safety precautions should therefore be taken if this function implementation
|
|
// interacts with data structures also handled by the application. The audio buffer class (\see cmApBuf.h)
|
|
// is designed to provide a safe and efficient way to communicate between
|
|
// the audio thread and the application.
|
|
typedef void (*cbFunc_t)( audioPacket_t* inPktArray, unsigned inPktCnt, audioPacket_t* outPktArray, unsigned outPktCnt );
|
|
|
|
rc_t initialize();
|
|
rc_t finalize();
|
|
unsigned deviceCount();
|
|
const char* deviceLabel( unsigned devIdx );
|
|
unsigned deviceLabelToIndex( const char* label );
|
|
unsigned deviceChannelCount( unsigned devIdx, bool inputFl );
|
|
|
|
// Get the current sample rate of a device. Note that if the device has both
|
|
// input and output capability then the sample rate is the same for both.
|
|
double deviceSampleRate( unsigned devIdx );
|
|
unsigned deviceFramesPerCycle( unsigned devIdx, bool inputFl );
|
|
|
|
// Configure a device.
|
|
// All devices must be setup before they are started.
|
|
// framesPerCycle is the requested number of samples per audio callback. The
|
|
// actual number of samples made from a callback may be smaller. See the note
|
|
// regarding this in audioPacket_t.
|
|
// If the device cannot support the requested configuration then the function
|
|
// will return an error code.
|
|
// If the device is started when this function is called then it will be
|
|
// automatically stopped and then restarted following the reconfiguration.
|
|
// If the reconfiguration fails then the device may not be restared.
|
|
rc_t deviceSetup( unsigned devIdx, double srate, unsigned framesPerCallback, cbFunc_t cbFunc, void* cbArg );
|
|
|
|
// Start a device. Note that the callback may be made prior to this function returning.
|
|
rc_t deviceStart( unsigned devIdx );
|
|
rc_t deviceStop( unsigned devIdx );
|
|
bool deviceIsStarted( unsigned devIdx );
|
|
|
|
// Print a report of all the current audio device configurations.
|
|
void report();
|
|
|
|
// Test the audio port by synthesizing a sine signal or passing audio through
|
|
// from the input to the output. This is also a good example of how to
|
|
// use all of the functions in the interface.
|
|
// Set runFl to false to print a report without starting any audio devices.
|
|
// See cmAudiotPortTest.c for usage example for this function.
|
|
rc_t test( bool runFl, int argc, const char** argv );
|
|
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
#endif
|