2024年3月22日发(作者：)

whos y

Name Size Bytes Class Attributes

y 16384x1 131072 double

The data type of

y

is

double

.

Request audio data in the native format of the file, and then view the data type of the sampled data

y

.

[y,Fs] = audioread(filename,'native');

whos y

Name Size Bytes Class Attributes

y 16384x1 32768 int16

The data type of

y

is now

int16

.

Input Arguments

string

Name of file to read, specified as a string that includes the file extension. If a path is specified, it can be absolute, relative or

partial.

Example:

'3'

Example:

'../3'

Example:

'C:3'

audioread

supports the following file formats.

Platform Support

All platformsWAVE (

.wav

)

OGG (

.ogg

)

FLAC (

.flac

)

AU (

.au

)

AIFF (

.aiff

,

.aif

)

AIFC (

.aifc

)

Windows

®

7 (or later), Macintosh, and Linux

®

MP3 (

.mp3

)

File Format

MPEG-4 AAC (

.m4a

,

.mp4

)

On Windows platforms prior to Windows 7,

audioread

does not read WAVE files with MP3 encoded data.

On Windows 7 (or later) platforms,

audioread

might also read any files supported by Windows Media

®

Foundation.

On Linux platforms,

audioread

might also read any files supported by GStreamer.

audioread

can extract audio from MPEG-4 (

.mp4

,

.m4v

) video files on Windows 7 or later, Macintosh, and Linux, and from Windows

Media Video (

.wmv

) and AVI (

.avi

) files on Windows 7 (or later) and Linux platforms.

[1,inf]

(default) | two-element vector of positive scalar integers

Audio samples to read, specified as a two-element vector of the form

[start,finish]

, where

start

and

finish

are the first and last

samples to read, and are positive scalar integers.

start

must be less than or equal to

finish

.

start

and

finish

must be less than the number of audio samples in the file,

You can use

inf

to indicate the last sample in the file.

Note: When reading a portion of some MP3 files on Windows 7 platforms,

audioread

might read a shifted range of samples.

This is due to a limitation in the underlying Windows Media Foundation framework.

When reading a portion of MP3 and M4A files on Linux platforms,

audioread

might read a shifted range of samples. This is due

to a limitation in the underlying GStreamer framework.

Example:

[1,100]

Data Types:

double

'double'

(default) |

'native'

Data format of audio data,

y

, specified as one of the following strings:

'double'

'native'

Double-precision normalized samples.

Samples in the native format found in the

file.

For compressed audio formats, such as MP3 and MPEG-4 AAC that do not store data in integer form,

'native'

defaults to

'single'

.

Output Arguments

matrix

Audio data in the file, returned as an

m

-by-

n

matrix, where

m

is the number of audio samples read and

n

is the number of audio

channels in the file.

If you do not specify

dataType

, or

dataType

is

'double'

, then

y

is of type

double

, and matrix elements are normalized values

between −1.0 and 1.0.

If

dataType

is

'native'

, then

y

can be one of several MATLAB data types, depending on the file format and

the

BitsPerSample

value of the input file. Call

audioinfo

to determine the

BitsPerSample

value of the file.

File Format

WAVE (

.wav

)

BitsPerSample

8

16

24

32

32

64

FLAC (

.flac

)8

16

24

MP3 (

.mp3

), MPEG-4 AAC

(

.m4a

,

.mp4

), OGG (

.ogg

), and

certain compressed WAVE

files

N/A

Data Type of y

uint8

int16

int32

int32

single

double

uint8

int16

int32

single

Data Range of y

0 ≤

y

≤ 255

-32768 ≤

y

≤ +32767

-2^32 ≤

y

≤ 2^32–1

-2^32 ≤

y

≤ 2^32–1

-1.0 ≤

y

≤ +1.0

-1.0 ≤

y

≤ +1.0

0 ≤

y

≤ 255

-32768 ≤

y

≤ +32767

-2^32 ≤

y

≤ 2^32–1

-1.0 ≤

y

≤ +1.0

Note: Where

y

is

single

or

double

and the

BitsPerSample

is 32 or 64, values in

y

might exceed −1.0 or +1.0.

positive scalar

Sample rate, in hertz, of audio data

y

, returned as a positive scalar.

Limitations

For MP3, MPEG-4 AAC, and AVI audio files on Windows 7 or later and Linux platforms,

audioread

might read fewer

samples than expected. On Windows 7 platforms, this is due to a limitation in the underlying Media Foundation framework.

On Linux platforms, this is due to a limitation in the underlying GStreamer framework. If you require sample-accurate

reading, work with WAV or FLAC files.

On Linux platforms,

audioread

reads MPEG-4 AAC files that contain single-channel data as stereo data.

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