Async 1.7.0
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Base class for handling audio devices. More...
#include <AsyncAudioDevice.h>
Public Types | |
enum | Mode { MODE_NONE , MODE_RD , MODE_WR , MODE_RDWR } |
The different modes to open a device in. More... | |
Public Member Functions | |
virtual size_t | readBlocksize (void)=0 |
Find out what the read (recording) blocksize is set to. | |
virtual size_t | writeBlocksize (void)=0 |
Find out what the write (playback) blocksize is set to. | |
virtual bool | isFullDuplexCapable (void)=0 |
Check if the audio device has full duplex capability. | |
bool | open (Mode mode) |
Open the audio device. | |
void | close (void) |
Close the audio device. | |
Mode | mode (void) const |
Get the current operating mode of this audio device. | |
virtual void | audioToWriteAvailable (void)=0 |
Tell the audio device handler that there are audio to be written in the buffer. | |
virtual void | flushSamples (void)=0 |
virtual int | samplesToWrite (void) const =0 |
Find out how many samples there are in the output buffer. | |
int | sampleRate (void) const |
Return the sample rate. | |
const std::string & | devName (void) const |
Return the device name. | |
Static Public Member Functions | |
static AudioDevice * | registerAudioIO (const std::string &dev_designator, AudioIO *audio_io) |
Register an AudioIO object with the given device name. | |
static void | unregisterAudioIO (AudioIO *audio_io) |
Unregister a previously registered AudioIO object. | |
static void | setSampleRate (int rate) |
Set the sample rate used when doing future opens. | |
static void | setBlocksize (size_t size) |
Set the blocksize used when opening audio devices. | |
static void | setBlockCount (size_t count) |
Set the buffer count used when opening audio devices. | |
static void | setChannels (size_t channels) |
Set the number of channels used when doing future opens. | |
static size_t | getChannels (void) |
Get the number of channels used for future opens. | |
Protected Member Functions | |
AudioDevice (const std::string &dev_name) | |
Constuctor. | |
virtual | ~AudioDevice (void) |
Destructor. | |
virtual bool | openDevice (Mode mode)=0 |
Open the audio device. | |
virtual void | closeDevice (void)=0 |
Close the audio device. | |
void | putBlocks (int16_t *buf, size_t frame_cnt) |
Write samples read from audio device to upper layers. | |
size_t | getBlocks (int16_t *buf, size_t block_cnt) |
Read samples from upper layers to write to audio device. | |
Protected Attributes | |
std::string | dev_name |
Static Protected Attributes | |
static int | sample_rate |
static size_t | block_size_hint |
static size_t | block_count_hint |
static size_t | channels |
Base class for handling audio devices.
This class implements a base class for supporting different audio devices. This class is not intended to be used by the end user of the Async library. It is used by the Async::AudioIO class, which is the Async API frontend for using audio in an application.
Definition at line 122 of file AsyncAudioDevice.h.
The different modes to open a device in.
Enumerator | |
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MODE_NONE | No mode. The same as close. |
MODE_RD | Read. |
MODE_WR | Write. |
MODE_RDWR | Both read and write. |
Definition at line 128 of file AsyncAudioDevice.h.
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explicitprotected |
Constuctor.
dev_name | The name of the device to associate this object with |
References dev_name.
Referenced by registerAudioIO().
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protectedvirtual |
Destructor.
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pure virtual |
Tell the audio device handler that there are audio to be written in the buffer.
void Async::AudioDevice::close | ( | void | ) |
Close the audio device.
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protectedpure virtual |
Close the audio device.
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inline |
Return the device name.
Definition at line 294 of file AsyncAudioDevice.h.
References dev_name.
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pure virtual |
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protected |
Read samples from upper layers to write to audio device.
buf Buffer which will be filled with frames of samples
block_cnt The size of the buffer counted in blocks
This function is used by an audio device implementation to get samples from upper layers to write to the actual audio device. The count is given in blocks. The buffer must be able to store the number given in block_cnt. Fewer blocks may be returned if the requested block count is not available. The number of samples a block contain is ret_blocks * writeBlocksize() * channels.
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inlinestatic |
Get the number of channels used for future opens.
Definition at line 234 of file AsyncAudioDevice.h.
References channels.
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pure virtual |
Check if the audio device has full duplex capability.
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inline |
Get the current operating mode of this audio device.
Definition at line 259 of file AsyncAudioDevice.h.
Referenced by open(), and openDevice().
bool Async::AudioDevice::open | ( | Mode | mode | ) |
Open the audio device.
mode | The mode to open the audio device in (See AudioIO::Mode) |
References mode().
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protectedpure virtual |
Open the audio device.
mode | The mode to open the audio device in (See AudioIO::Mode) |
References mode().
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protected |
Write samples read from audio device to upper layers.
buf | Buffer containing frames of samples to write |
frame_cnt | The number of frames of samples in the buffer |
This function is used by an audio device implementation to write audio samples recorded from the actual audio device to the upper software layers, for further processing. The number of samples is given as frames. A frame contains one sample per channel starting with channel 0. Frames are put in the buffer one after the other. Thus, the sample buffer should contain frame_cnt * channels samples.
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pure virtual |
Find out what the read (recording) blocksize is set to.
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static |
Register an AudioIO object with the given device name.
dev_designator | The name of the audio device |
audio_io | A previously created AudioIO object |
This function is used to register an AudioIO object with the given audio device. If an AudioDevice object already exist for the given device, it is returned. If there is no AudioDevice object for the given device, a new one is created.
References AudioDevice().
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inline |
Return the sample rate.
Definition at line 288 of file AsyncAudioDevice.h.
References sample_rate.
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pure virtual |
Find out how many samples there are in the output buffer.
This function can be used to find out how many samples there are in the output buffer at the moment. This can for example be used to find out how long it will take before the output buffer has been flushed.
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inlinestatic |
Set the buffer count used when opening audio devices.
count | The buffer count to use |
Use this function to set the buffer count used when opening audio devices. The buffer count is the maximum number of blocks the driver will buffer when reading and writing audio to/from the sound card. Lower numbers give less delay but could cause choppy audio if the computer is too slow. This is a global setting so all sound cards will be affected. Already opened sound cards will not be affected.
Definition at line 211 of file AsyncAudioDevice.h.
References block_count_hint.
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inlinestatic |
Set the blocksize used when opening audio devices.
size | The blocksize, in samples per channel, to use |
Use this function to set the block size used when opening audio devices. The block size is the size of the blocks used when reading and writing audio to/from the sound card. Smaller blocks give less delay but could cause choppy audio if the computer is too slow. The blocksize is set as samples per channel. For example, a blocksize of 256 samples at 8kHz sample rate will give a delay of 256/8000 = 32ms. This is a global setting so all sound cards will be affected. Already opened sound cards will not be affected.
Definition at line 181 of file AsyncAudioDevice.h.
References block_size_hint.
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inlinestatic |
Set the number of channels used when doing future opens.
channels | The number of channels to use |
Use this function to set the number of channels used when opening audio devices. This is a global setting so all sound cards will be affected. Already opened sound cards will not be affected.
Definition at line 225 of file AsyncAudioDevice.h.
References channels.
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inlinestatic |
Set the sample rate used when doing future opens.
rate | The sampling rate to use |
Use this function to set the sample rate used when opening audio devices. This is a global setting so all sound cards will be affected. Already opened sound cards will not be affected.
Definition at line 165 of file AsyncAudioDevice.h.
References sample_rate.
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static |
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pure virtual |
Find out what the write (playback) blocksize is set to.
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staticprotected |
Definition at line 300 of file AsyncAudioDevice.h.
Referenced by setBlockCount().
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staticprotected |
Definition at line 299 of file AsyncAudioDevice.h.
Referenced by setBlocksize().
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staticprotected |
Definition at line 301 of file AsyncAudioDevice.h.
Referenced by getChannels(), and setChannels().
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protected |
Definition at line 303 of file AsyncAudioDevice.h.
Referenced by AudioDevice(), and devName().
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staticprotected |
Definition at line 298 of file AsyncAudioDevice.h.
Referenced by sampleRate(), and setSampleRate().