Class PlaybackWav
- class PlaybackWav
Description
A class used for control and playback of .wav file format audio data.
Syntax
class PlaybackWav
Members
Public Constructors
PlaybackWav::PlaybackWav |
Create an instance of the PlaybackWav class |
Public Methods
PlaybackWav::openFile |
Open a .wav file for playback |
PlaybackWav::closeFile |
Close a previously opened file |
PlaybackWav::fileOpened |
Check if a .wav file is already opened |
PlaybackWav::getSampleRate |
Get the sample rate of the .wav file |
PlaybackWav::getChannelCount |
Get the number of audio channels in the .wav file |
PlaybackWav::getBitDepth |
Get the bit depth of each sample in the .wav file |
PlaybackWav::getLengthMillis |
Get the playback length of the .wav file in milliseconds |
PlaybackWav::getPositionMillis |
Get the current playback position in milliseconds |
PlaybackWav::setPositionMillis |
Set the current playback position in milliseconds |
PlaybackWav::millisToBytes |
Convert a playback duration to equivalent number of bytes |
PlaybackWav::bytesToMillis |
Convert number of bytes to an equivalent playback duration |
PlaybackWav::readAudioData |
Read audio data from the .wav file |
- PlaybackWav::PlaybackWav
Description
Create a PlaybackWav class object.
Syntax
void PlaybackWav(void);
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
Example Code
NA
Notes and Warnings
NA
- PlaybackWav::fileOpened
Description
Check if a .wav file is already opened.
Syntax
bool fileOpened(void);
Parameters
The function requires no input parameter.
Returns
The function returns true if a .wav file is already open, false otherwise.
Example Code
Example: RecordPlaybackWav
Notes and Warnings
NA
- PlaybackWav::getSampleRate
Description
Get the sample rate of the .wav file.
Syntax
uint32_t getSampleRate(void);
Parameters
The function requires no input parameter.
Returns
The function returns sampling rate encoded in the .wav file header.
Example Code
Example: PlaybackWavFile
Notes and Warnings
NA
- PlaybackWav::getChannelCount
Description
Get the number of audio channels in the .wav file.
Syntax
uint16_t getChannelCount(void);
Parameters
The function requires no input parameter.
Returns
The function returns channel count encoded in the .wav file header.
Example Code
Example: PlaybackWavFile
Notes and Warnings
NA
- PlaybackWav::getBitDepth
Description
Get the bit depth of each sample in the .wav file.
Syntax
uint16_t getBitDepth(void);
Parameters
The function requires no input parameter.
Returns
The function returns bit depth encoded in the .wav file header.
Example Code
Example: PlaybackWavFile
Notes and Warnings
NA
- PlaybackWav::getLengthMillis
Description
Get the playback length of the .wav file in milliseconds.
Syntax
uint32_t getLengthMillis(void);
Parameters
The function requires no input parameter.
Returns
The function returns the total playback length of the currently open .wav file in milliseconds.
Example Code
Example: PlaybackWavFile
Notes and Warnings
NA
- PlaybackWav::getPositionMillis
Description
Get the current playback position in milliseconds.
Syntax
uint32_t getPositionMillis(void);
Parameters
The function requires no input parameter.
Returns
The function returns the current playback position of the currently open .wav file in milliseconds.
Example Code
Example: PlaybackWavFile
Notes and Warnings
NA
- 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
The function returns nothing.
Example Code
Example: PlaybackWavFile
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::millisToBytes
Description
Convert a playback duration to equivalent number of bytes.
Syntax
uint32_t millisToBytes(uint32_t ms);
Parameters
ms
: playback duration in milliseconds.
Returns
The function returns the number of bytes that is equivalent to the input playback duration, converted using the current sample rate, number of channels and bit depth.
Example Code
NA
Notes and Warnings
NA
- PlaybackWav::bytesToMillis
Description
Convert number of bytes to an equivalent playback duration.
Syntax
uint32_t bytesToMillis(uint32_t bytes);
Parameters
bytes
: playback duration in number of bytes.
Returns
The 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
NA
- PlaybackWav::read
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 array to store data read from .wav file.
len
: number of audio samples to read from .wav file.
Returns
The function returns number of audio samples read.
Example Code
Example: PlaybackWavFile
Notes and Warnings
NA