MATLAB Function Reference

mmfileinfo

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Information about multimedia file

Syntax

info = mmfileinfo(filename)

Description

info = mmfileinfo(filename) returns a structure, info, with fields containing information about the contents of the multimedia file identified by filename. The filename input is a string enclosed in single quotes.

Note mmfileinfo can be used only on Windows systems.

If filename is a URL, mmfileinfo might take a long time to return because it must first download the file. For large files, downloading can take several minutes. To avoid blocking the MATLAB command line while this processing takes place, download the file before calling mmfileinfo.

The info structure contains the following fields, listed in the order they appear in the structure.

Field	Description
`Filename`	String indicating the name of the file
`Duration`	Length of the file in seconds
`Audio`	Structure containing information about the audio data in the file. See Audio Data for more information about this data structure.
`Video`	Structure containing information about the video data in the file. See Video Data for more information about this data structure.

Audio Data

The Audio structure contains the following fields, listed in the order they appear in the structure. If the file does not contain audio data, the fields in the structure are empty.

Field	Description
`Format`	Text string, indicating the audio format
`NumberOfChannels`	Number of audio channels

Video Data

The Video structure contains the following fields, listed in the order they appear in the structure.

Field	Description
`Format`	Text string, indicating the video format
`Height`	Height of the video frame
`Width`	Width of the video frame

Examples

This example gets information about the contents of a file containing audio data.

info = mmfileinfo('my_audio_data.mp3')

info = 

    Filename: 'my_audio_data.mp3'
    Duration: 1.6030e+002
       Audio: [1x1 struct]
       Video: [1x1 struct]

To look at the information returned about the audio data in the file, examine the fields in the Audio structure.

audio_data = info.Audio

audio_data = 

              Format: 'MPEGLAYER3'
    NumberOfChannels: 2

Because the file contains only audio data, the fields in the Video structure are empty.

info.Video

ans = 

    Format: ''
    Height: []
     Width: []

mlock

mmreader

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