PlaybackWav Class

PlaybackWav Class

Description
A class used for controlling and playback of .wav file format audio data.

Syntax
class PlaybackWav

Members

Public Constructors 
PlaybackWav::PlaybackWavConstructs a PlaybackWav class object.
Public Methods 
PlaybackWav::openFileOpen a .wav audio file for playback.
PlaybackWav::closeFileClose a previously opened audio file.
PlaybackWav::fileOpenedCheck if a .wav file is already opened.
PlaybackWav::getSampleRateGet the sample rate of the .wav file.
PlaybackWav::getChannelCountGet the number of audio channels in the .wav file.
PlaybackWav::getBitDepthGet the bit depth of each sample in the .wav file.
PlaybackWav::getLengthMillisGet the playback length of the .wav file in milliseconds.
PlaybackWav::getPositionMillisGet the current playback position in milliseconds.
PlaybackWav::setPositionMillisSet the current playback position in milliseconds.
PlaybackWav::millisToBytesConvert a playback duration from milliseconds to bytes.
PlaybackWav::bytesToMillisConvert a playback duration from bytes to milliseconds.
PlaybackWav::readAudioDataRead audio data from the .wav file.

PlaybackWav::PlaybackWav

Description
Constructs a PlaybackWav class object.

Syntax
void PlaybackWav(void);

Parameters
NA

Returns
NA

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::openFile

Description
Open a .wav file for playback.

Syntax
void openFile(const char* absFilepath);

Parameters
absFilepath: The filepath of the .wav file that will be opened.

Returns
NA

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::closeFile

Description
Close a previously opened audio file.

Syntax
void closeFile(void);

Parameters
NA

Returns
NA

Example Code
NA

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::fileOpened

Description
Check if a .wav file is already opened.

Syntax
bool fileOpened(void);

Parameters
NA

Returns
This function returns true if a .wav file is already open, false otherwise.

Example Code
Example: RecordPlaybackWav
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::getSampleRate

Description
Get the sample rate of the .wav file.

Syntax
uint32_t getSampleRate(void);

Parameters
NA

Returns
This function returns sampling rate encoded in the .wav file header.

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::getChannelCount

Description
Get the number of audio channels in the .wav file.

Syntax
uint16_t getChannelCount(void);

Parameters
NA

Returns
This function returns channel count encoded in the .wav file header.

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::getBitDepth

Description
Get the bit depth of each sample in the .wav file.

Syntax
uint16_t getBitDepth(void);

Parameters
NA

Returns
This function returns bit depth encoded in the .wav file header.

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::getLengthMillis

Description
Get the playback length of the .wav file in milliseconds.

Syntax
uint32_t getLengthMillis(void);

Parameters
NA

Returns
This function returns the total playback length of the currently open .wav file in milliseconds.

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::getPositionMillis

Description
Get the current playback position in milliseconds.

Syntax
uint32_t getPositionMillis(void);

Parameters
NA

Returns
This function returns the current playback position of the currently open .wav file in milliseconds.

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::setPositionMillis

Description
Set the current playback position in milliseconds.

Syntax
void setPositionMillis(uint32_t pos);

Parameters
pos: The desired playback position expressed in milliseconds.

Returns
NA

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
Any changes to playback position will only take effect on the next call to PlaybackWav::readAudioData. If the desired playback position is beyond the total playback length of the file, the playback position will be set to the end of file, and no audio data will be output on subsequent data reads.
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::millisToBytes

Description
Convert a playback duration from milliseconds to bytes.

Syntax
uint32_t millisToBytes(uint32_t ms);

Parameters
ms: playback duration in milliseconds.

Returns
This function returns the number of bytes that is equivalent to the input playback duration in ms, converted using the current sample rate, number of channels and bit depth.

Example Code
NA

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::bytesToMillis

Description
Convert a playback duration from bytes to milliseconds.

Syntax
uint32_t bytesToMillis(uint32_t bytes);

Parameters
bytes: playback duration in number of bytes.

Returns
This function returns the time duration in milliseconds that is equivalent to the input number of bytes, converted using the current sample rate, number of channels and bit depth.

Example Code
NA

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

PlaybackWav::readAudioData

Description
Read audio data from the .wav file.

Syntax
uint32_t readAudioData(int8_t* dst, uint32_t len);
uint32_t readAudioData(int16_t* dst, uint32_t len);

Parameters
dst: Pointer to an array that stores audio data from .wav file to be read .
len: number of audio samples to be read from .wav file.

Returns
This function returns number of audio samples to be read.

Example Code
Example: PlaybackWavFile
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“PlaybackWav.h” must be included to use the class function.

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