maix::audio

maix.audio module

This is maix::audio module of MaixCDK.
All of these elements are in namespace maix::audio.

For MaixCDK developer: DO NOT edit this doc file manually, this doc is auto generated!

Module

No module

Enum

Format

Audio type

item	describe
values	FMT_NONE: format invalid FMT_S8: unsigned 8 bits FMT_S16_LE: signed 16 bits, little endian FMT_S32_LE: signed 32 bits, little endian FMT_S16_BE: signed 16 bits, big endian FMT_S32_BE: signed 32 bits, big endian FMT_U8: unsigned 8 bits FMT_U16_LE: unsigned 16 bits, little endian FMT_U32_LE: unsigned 32 bits, little endian FMT_U16_BE: unsigned 16 bits, big endian FMT_U32_BE: unsigned 32 bits, big endian

item

describe

values

FMT_NONE: format invalid
FMT_S8: unsigned 8 bits
FMT_S16_LE: signed 16 bits, little endian
FMT_S32_LE: signed 32 bits, little endian
FMT_S16_BE: signed 16 bits, big endian
FMT_S32_BE: signed 32 bits, big endian
FMT_U8: unsigned 8 bits
FMT_U16_LE: unsigned 16 bits, little endian
FMT_U32_LE: unsigned 32 bits, little endian
FMT_U16_BE: unsigned 16 bits, big endian
FMT_U32_BE: unsigned 32 bits, big endian

C++ defination code:

enum Format
    {
        FMT_NONE = 0,       // format invalid
        FMT_S8,             // unsigned 8 bits
        FMT_S16_LE,         // signed 16 bits, little endian
        FMT_S32_LE,         // signed 32 bits, little endian
        FMT_S16_BE,         // signed 16 bits, big endian
        FMT_S32_BE,         // signed 32 bits, big endian
        FMT_U8,             // unsigned 8 bits
        FMT_U16_LE,         // unsigned 16 bits, little endian
        FMT_U32_LE,         // unsigned 32 bits, little endian
        FMT_U16_BE,         // unsigned 16 bits, big endian
        FMT_U32_BE,         // unsigned 32 bits, big endian
    }

Variable

fmt_bits

Map the audio format to the number of bits

item	description
param	format: audio format
return	number of bits
value	{ 0, 8, 16, 32, 16, 32, 8, 16, 32, 16, 32 }
readonly	True

C++ defination code:

const std::vector<int> fmt_bits = {
        0, 8, 16, 32, 16, 32, 8, 16, 32, 16, 32
    }

Function

Class

File

Audio file reader

C++ defination code:
class File: public AudioFile<float>

init

Construct a new File object.

item	description
type	func
param	path: wav or pcm file path sample_rate: sample rate, need to be filled in when parsing .pcm files channels: channels, need to be filled in when parsing .pcm files bits_per_sample: bits per sample, need to be filled in when parsing .pcm files
static	False

C++ defination code:

File(int sample_rate = 16000, int channels = 1, int bits_per_sample = 16)

load

Loads an audio file from a given file path.

item	description
type	func
param	path: The file path to load the audio file from. sample_rate: The sample rate of the audio file. Only required for PCM files channels: The number of channels in the audio file. Only required for PCM files bits_per_sample: The number of bits per sample in the audio file. Only required for PCM files
return	An error code indicating whether the operation was successful or not.
static	False

C++ defination code:

err::Err load(std::string path, int sample_rate = 16000, int channels = 1, int bits_per_sample = 16)

save

Saves an audio file to a given file path.

item	description
type	func
param	path: The path to the file where the audio file will be saved.
return	An error code indicating whether the operation was successful or not.
static	False

C++ defination code:
err::Err save(std::string path)

get_pcm

Get pcm data

item	description
type	func
return	pcm data. datatype @see Bytes
static	False

C++ defination code:
Bytes *get_pcm(bool copy = true)

set_pcm

Set pcm data

item	description
type	func
param	new_pcm: pcm data. datatype @see Bytes
static	False

C++ defination code:

void set_pcm(Bytes *new_pcm, bool copy = true)

sample_bits

Get sample bit

item	description
type	func
param	new_sample_bit: if new_sample_bit > 0, set sample bit
return	current sample bit
static	False

C++ defination code:
int sample_bits(int new_sample_bits = -1)

channels

Get channels

item	description
type	func
param	new_channels: if new_channels > 0, change channels
return	current channels
static	False

C++ defination code:
int channels(int new_channels = -1)

sample_rate

Get sample rate

item	description
type	func
param	new_sample_rate: if new_sample_rate > 0, change sample rate
return	current sample rate
static	False

C++ defination code:
int sample_rate(int new_sample_rate = -1)

Recorder

Recorder class

C++ defination code:
class Recorder

Recorder

Construct a new Recorder object. currectly only pcm and wav formats supported.

item	description
type	func
param	path: record path. the path determines the location where you save the file, if path is none, the audio module will not save file. sample_rate: record sample rate, default is 48000(48KHz), means 48000 samples per second. format: record sample format, default is audio::Format::FMT_S16_LE, means sampling 16 bits at a time and save as signed 16 bits, little endian. see @audio::Format channel: record sample channel, default is 1, means 1 channel sampling at the same time block: block record, default is true, means block record, if false, record will not block
static	False

C++ defination code:

Recorder(std::string path = std::string(), int sample_rate = 48000, audio::Format format = audio::Format::FMT_S16_LE, int channel = 1, bool block = true)

volume

Set/Get record volume

item	description
type	func
param	value: volume value, If you use this parameter, audio will set the value to volume, if you don't, it will return the current volume. range is [0, 100].
return	the current volume
static	False

C++ defination code:
int volume(int value = -1)

mute

Mute

item	description
type	func
note	MaixCAM2 dose not support this api.
param	data: mute data, If you set this parameter to true, audio will set the value to mute, if you don't, it will return the current mute status.
return	Returns whether mute is currently enabled.
static	False

C++ defination code:
bool mute(int data = -1)

reset

Reset record status

item	description
type	func
param	start: start prepare audio data, default is True
static	False

C++ defination code:
void reset(bool start = true)

record

Record, Read all cached data in buffer and return. If there is no audio data in the buffer, may return empty data.

item	description
type	func
note	1. Do not set the time too low, for example: 1ms, as the buffer may not be ready with audio data, which could corrupt the internal state. 2. In non-blocking mode, you need to actively execute reset() before you can start capturing audio. Additionally, in non-blocking mode, if the buffer does not have enough data, only the currently prepared audio data will be returned. As a result, the length of the actual output audio data may not match the length of the captured audio data.
param	record_ms: Block and record audio data lasting `record_ms` milliseconds and save it to a file, the return value does not return audio data. Only valid if the initialisation `path` is set.
return	pcm data. datatype @see Bytes. If you pass in record_ms parameter, the return value is an empty Bytes object.
static	False

C++ defination code:
maix::Bytes *record(int record_ms = -1)

record_bytes

Record, Read all cached data in buffer and return. If there is no audio data in the buffer, may return empty data.

item	description
type	func
note	1. This interface is experimental and may be removed in the future. 2. In non-blocking mode, you need to actively execute reset() before you can start capturing audio. Additionally, in non-blocking mode, if the buffer does not have enough data, only the currently prepared audio data will be returned. As a result, the length of the actual output audio data may not match the length of the captured audio data.
param	record_size: Record audio data of size record_size.
return	pcm data. datatype @see Bytes. If you pass in record_ms parameter, the return value is an empty Bytes object.
static	False

C++ defination code:

maix::Bytes *record_bytes(int record_size = -1)

finish

Finish the record, if you have passed in the path, this api will save the audio data to file.

item	description
type	func
return	error code, err::ERR_NONE means success, others means failed
static	False

C++ defination code:
err::Err finish()

frame_size

Returns the number of bytes for frame_count frames.

item	description
type	func
param	frame_count: frame count
return	frame bytes
static	False

C++ defination code:
int frame_size(int frame_count = 1)

get_remaining_frames

Return the number of frames available for reading during recording, unit is frame.

item	description
type	func
note	1. MaixCAM2 dose not support this api. 2. The number of bytes per frame can be calculated using frame_size().
return	remaining frames
static	False

C++ defination code:
int get_remaining_frames()

period_size

Set/Get the audio buffer size, unit: frame.

item	description
type	func
note	1. Generally, the buffer size needs to be modified during non-blocking operations. 2. The number of bytes per frame can be calculated using frame_size().
param	period_size: When period_size is less than 0, the current value of period_size will be returned; when period_size is greater than 0, period_size will be updated, and the size of period_size after setting will be returned.
return	the current period size
static	False

C++ defination code:
int period_size(int period_size = -1)

period_count

Set/Get the audio buffer count, unit: frame.

item	description
type	func
note	Generally, the buffer size needs to be modified during non-blocking operations.
param	period_count: When period_count is less than 0, the current value of period_count will be returned; when period_count is greater than 0, period_count will be updated, and the size of period_count after setting will be returned.
return	the current period size
static	False

C++ defination code:
int period_count(int period_count = -1)

sample_rate

Get sample rate

item	description
type	func
return	returns sample rate
static	False

C++ defination code:
int sample_rate()

format

Get sample format

item	description
type	func
return	returns sample format
static	False

C++ defination code:
audio::Format format()

channel

Get sample channel

item	description
type	func
return	returns sample channel
static	False

C++ defination code:
int channel()

Player

Player class

C++ defination code:
class Player

Player

Construct a new Player object

item	description
type	func
param	path: player path. the path determines the location where you save the file, if path is none, the audio module will not save file. sample_rate: player sample rate, default is 48000(48KHz), means 48000 samples per second. format: player sample format, default is audio::Format::FMT_S16_LE, means sampling 16 bits at a time and save as signed 16 bits, little endian. see @audio::Format channel: player sample channel, default is 1, means 1 channel sampling at the same time block: block record, default is true, means block record, if false, record will not block
static	False

C++ defination code:

Player(std::string path = std::string(), int sample_rate = 48000, audio::Format format = audio::Format::FMT_S16_LE, int channel = 1, bool block = true)

volume

Set/Get player volume

item	description
type	func
param	value: volume value, If you use this parameter, audio will set the value to volume, if you don't, it will return the current volume. range is [0, 100].
return	the current volume
static	False

C++ defination code:
int volume(int value = -1)

play

Play

item	description
type	func
param	data: audio data, must be raw data
return	error code, err::ERR_NONE means success, others means failed
static	False

C++ defination code:

err::Err play(maix::Bytes *data = maix::audio::Player::NoneBytes)

frame_size

Returns the number of bytes for frame_count frames.

item	description
type	func
param	frame_count: frame count
return	frame bytes
static	False

C++ defination code:
int frame_size(int frame_count = 1)

get_remaining_frames

Return the number of idle frames available for writing during playback, unit: frame. if there are no idle frames, it will cause blocking.

item	description
type	func
note	1. MaixCAM2 dose not support this api. 2. The number of bytes per frame can be calculated using frame_size().
return	remaining frames
static	False

C++ defination code:
int get_remaining_frames()

period_size

Set/Get the audio buffer size, unit: frame.

item	description
type	func
note	1. Generally, the buffer size needs to be modified during non-blocking operations. 2. The number of bytes per frame can be calculated using frame_size().
param	period_size: When period_size is less than 0, the current value of period_size will be returned; when period_size is greater than 0, period_size will be updated, and the size of period_size after setting will be returned.
return	the current period size
static	False

C++ defination code:
int period_size(int period_size = -1)

period_count

Set/Get the audio buffer count, unit: frame.

item	description
type	func
note	Generally, the buffer size needs to be modified during non-blocking operations.
param	period_count: When period_count is less than 0, the current value of period_count will be returned; when period_count is greater than 0, period_count will be updated, and the size of period_count after setting will be returned.
return	the current period size
static	False

C++ defination code:
int period_count(int period_count = -1)

reset

Reset player status

item	description
type	func
param	start: start play audio data, default is False
static	False

C++ defination code:
void reset(bool start = false)

sample_rate

Get sample rate

item	description
type	func
return	returns sample rate
static	False

C++ defination code:
int sample_rate()

format

Get sample format

item	description
type	func
return	returns sample format
static	False

C++ defination code:
audio::Format format()

channel

Get sample channel

item	description
type	func
return	returns sample channel
static	False

C++ defination code:
int channel()

protocol

image

MaixCDK

maix::audio

Module

Enum

Format

Variable

fmt_bits

Function

Class

File

__init__

load

save

get_pcm

set_pcm

sample_bits

channels

sample_rate

Recorder

Recorder

volume

mute

reset

record

record_bytes

finish

frame_size

get_remaining_frames

period_size

period_count

sample_rate

format

channel

Player

Player

volume

play

frame_size

get_remaining_frames

period_size

period_count

reset

sample_rate

format

channel

init