152 рядки
6.3 KiB
C
152 рядки
6.3 KiB
C
/// \file cmAudioPort.h
|
|
/// \brief Cross platform audio I/O interface.
|
|
///
|
|
/// 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.
|
|
///
|
|
///
|
|
/// Usage example and testing code:
|
|
/// See cmApPortTest() and cmAudioSysTest().
|
|
/// \snippet cmAudioPort.c cmAudioPortExample
|
|
///
|
|
#ifndef cmAudioPort_h
|
|
#define cmAudioPort_h
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
typedef unsigned cmApRC_t; ///< Audio port interface result code.
|
|
typedef float cmApSample_t; ///< Audio sample type.
|
|
|
|
enum
|
|
{
|
|
kOkApRC =0,
|
|
kSysErrApRC,
|
|
kInvalidDevIdApRC,
|
|
kAudioPortFileFailApRC,
|
|
kThreadFailApRC
|
|
};
|
|
|
|
// cmApAudioPacket_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 cmApAudioPacket_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 value passed in cmApDeviceSetup()
|
|
} cmApAudioPacket_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 (*cmApCallbackPtr_t)( cmApAudioPacket_t* inPktArray, unsigned inPktCnt, cmApAudioPacket_t* outPktArray, unsigned outPktCnt );
|
|
|
|
/// Setup the audio port management object for this machine.
|
|
cmApRC_t cmApInitialize( cmRpt_t* rpt );
|
|
|
|
/// Stop all audio devices and release any resources held
|
|
/// by the audio port management object.
|
|
cmApRC_t cmApFinalize();
|
|
|
|
/// Return the count of audio devices attached to this machine.
|
|
unsigned cmApDeviceCount();
|
|
|
|
/// Get a textual description of the device at index 'devIdx'.
|
|
const char* cmApDeviceLabel( unsigned devIdx );
|
|
|
|
/// Given an audio device label return the associated device index.
|
|
unsigned cmApDeviceLabelToIndex( const cmChar_t* label );
|
|
|
|
/// Get the count of audio input or output channesl on device at index 'devIdx'.
|
|
unsigned cmApDeviceChannelCount( 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 cmApDeviceSampleRate( unsigned devIdx );
|
|
|
|
/// Get the count of samples per callback for the input or output for this device.
|
|
unsigned cmApDeviceFramesPerCycle( 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 cmApAudioPacket_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.
|
|
cmApRC_t cmApDeviceSetup(
|
|
unsigned devIdx,
|
|
double srate,
|
|
unsigned framesPerCycle,
|
|
cmApCallbackPtr_t callbackPtr,
|
|
void* userCbPtr );
|
|
|
|
/// Start a device. Note that the callback may be made prior to this function returning.
|
|
cmApRC_t cmApDeviceStart( unsigned devIdx );
|
|
|
|
/// Stop a device.
|
|
cmApRC_t cmApDeviceStop( unsigned devIdx );
|
|
|
|
/// Return true if the device is currently started.
|
|
bool cmApDeviceIsStarted( unsigned devIdx );
|
|
|
|
/// Print a report of all the current audio device configurations.
|
|
void cmApReport( cmRpt_t* rpt );
|
|
|
|
/// 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.
|
|
int cmApPortTest(bool runFl, cmRpt_t* rpt, int argc, const char* argv[] );
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif
|