audioinfo

Information about audio file

Syntax

info = audioinfo(filename)

Description

info = audioinfo(filename) returns information about the contents of the audio file specified by filename.

Examples

Get Information About Audio File

Create a WAVE file from the example file handel.mat, and get information about the file.

Create a WAVE (.wav) file in the current folder.

load handel.mat
filename = 'C:\Temp\handel.wav';
audiowrite(filename,y,Fs);
clear y Fs

Use audioinfo to return information about the WAVE file.

info = audioinfo(filename)

info = 

  struct with fields:

             Filename: 'C:\Temp\handel.wav'
    CompressionMethod: 'Uncompressed'
          NumChannels: 1
           SampleRate: 8192
         TotalSamples: 73113
             Duration: 8.9249
                Title: []
              Comment: []
               Artist: []
        BitsPerSample: 16

Input Arguments

filename — Name of file

character vector | string scalar

Name of file, specified as a character vector or string scalar that includes the file extension.

Depending on the location of your file, filename can take on one of these forms.

Current folder	Specify the name of the file in filename. Example: 'sample_audio.wav'
Other folders	If the file is not in the current folder or in a folder on the MATLAB® path, then specify the full or relative path name in filename. Example: 'C:\myFolder\myFile.sample_audio.wav' Example: 'myFolder\sample_audio.mp3'
Internet URL	If the file is specified as an internet uniform resource locator (URL), then filename must contain the protocol type 'http://' or 'https://'. Example: 'http://hostname/path_to_file/sample_audio.mp3'
Remote Location	If the file is stored at a remote location, then filename must contain the full path of the file specified with the form: scheme_name://path_to_file/my_file.ext Based on the remote location, scheme_name can be one of the values in this table. Remote Location scheme_name Amazon S3™ s3 Windows Azure® Blob Storage wasb, wasbs HDFS™ hdfs For more information, see Work with Remote Data. Example: 's3://bucketname/path_to_file/sample_audio.mp3'

Example: 'myFile.mp3'

Example: '../myFile.mp3'

Example: 'C:\temp\myFile.mp3'

audioinfo supports the following file formats.

Platform Support	File Format
All platforms	AIFC (.aifc)
	AIFF (.aiff, .aif)
	AU (.au)
	FLAC (.flac)
	OGG (.ogg)
	OPUS (.opus)
	WAVE (.wav)
Windows® 7 (or later), Macintosh, and Linux®	MP3 (.mp3)
	MPEG-4 AAC (.m4a, .mp4)

On Windows 7 platforms (or later), audioinfo might also return information about the contents of any files supported by Windows Media^® Foundation.

On Linux platforms, audioinfo might also return information about the contents of any files supported by GStreamer.

audioinfo can extract audio metadata from MPEG-4 (.mp4, .m4v) video files on Windows 7 or later, macOS 10.7 Lion or higher, and Linux, and from Windows Media Video (.wmv) and AVI (.avi) files on Windows 7 (or later) and Linux platforms.

Data Types: char | string

Output Arguments

info — Information about audio file

structure

Information about audio file, returned as a structure. info can contain the following fields.

Field Name	Description	Data Type
Filename	Filename including the absolute path to the file and the file extension.	character vector
CompressionMethod	Compression method used.	character vector
NumChannels	Number of audio channels encoded in the audio file.	double
SampleRate	Sample rate of the audio data in the file, in hertz.	double
TotalSamples	Total number of audio samples in the file.	double
Duration	Duration of the file, in seconds.	double
BitsPerSample	Number of bits per sample encoded in the audio file. Only valid for WAVE (.wav) and FLAC (.flac) files.	double
BitRate	Number of kilobits per second (kbit/s) used for compressed audio files. Only valid for MP3 (.mp3) and MPEG-4 Audio (.m4a, .mp4) files.	double
Title	Value of 'Title', if any.	character vector
Artist	Value of 'Artist', if any.	character vector
Comment	Value of 'Comment', if any.	character vector

Note

The BitRate property returns the actual bit rate on Mac platforms, and not the encoded bit rate. This means that bit rate values might be lower than specified at the time of the encoding, depending on the source data.

Note

On Mac platforms, audioinfo returns metadata from .m4a and .mp4 files only on macOS 10.7 Lion or higher. Previous versions of macOS will not read the 'Title', 'Author', or 'Comment' fields.

Limitations

• For MP3 and MPEG-4 AAC audio files on Windows 7 or later and Linux platforms, audioinfo might report fewer samples than expected. On Linux platforms, this is caused by a limitation in the underlying GStreamer framework.

• On Linux platforms, audioinfo interprets single channel data in MPEG-4 AAC files as stereo data.

• For MP3 files on Windows platforms, audioinfo might not report values in the Artist, Title, or Comment fields of the output structure. This omission is caused by a limitation in the underlying Windows Media Foundation library.

Version History

Introduced in R2012b

R2022a: Analyze Opus (.opus) audio files

You can analyze Ogg Opus audio files.

R2021a: Analyze audio files from an HTTP or HTTPS URL

You can analyze audio files from an internet URL by specifying filename as a string or character vector that contains the protocol type 'http://' or 'https://'.

R2020b: Analyze audio files from a remote location

You can analyze audio files stored in remote locations, such as Amazon S3, Windows Azure Blob Storage, and HDFS.