Video and audio files in MATLAB® and their supported file formats and codecs.
For video data, the term “file format” often refers to either the container format or the codec. A container format describes the layout of the file, while a codec describes how to encode/decode the video data. Many container formats can hold data encoded with different codecs.
To read a video file, any application must:
Recognize the container format (such as AVI).
Have access to the codec that can decode the video data stored in the
file. Some codecs are part of standard Windows® and Macintosh system installations, and allow you to play video in
Media® Player or QuickTime. In MATLAB,
VideoReader can access most, but not
all, of these codecs.
Properly use the codec to decode the video data in the file.
VideoReader cannot always read files associated
with codecs that were not part of your original system
VideoReader to read video files in MATLAB. The file formats that
vary by platform, and have no restrictions on file extensions.
AVI, including uncompressed, indexed, grayscale, and
Motion JPEG-encoded video (
Windows 7 or later
MPEG-4, including H.264 encoded video (
Most formats supported by QuickTime Player, including:
Note: For OS X Yosemite (Version 10.10) and
later, MPEG-4/H.264 files written using
Any format supported by your installed plug-ins for GStreamer 1.0 or higher, as listed
on https://gstreamer.freedesktop.org/documentation/plugins_doc.html, including Ogg Theora (
This example shows how to view the codec associated with a video file, using the
Store information about the sample video file,
shuttle.avi, in a structure array named
info structure contains the following fields:
info = mmfileinfo('shuttle.avi');
Show the properties in the command window by displaying the fields of the
info structure. For example, to view information under the
Video field, type
ans = struct with fields: Format: 'Motion JPEG' Height: 288 Width: 512
shuttle.avi, uses the Motion JPEG codec.
You might be unable to read a video file if MATLAB cannot access the appropriate codec. 64-bit applications use 64-bit codec libraries, while 32-bit applications use 32-bit codec libraries. For example, when working with 64-bit MATLAB, you cannot read video files that require access to a 32-bit codec installed on your system. To read these files, try one of the following:
Install a 64-bit codec that supports this file format. Then, try reading the file using 64-bit MATLAB.
Re-encode the file into a different format with a 64-bit codec that is installed on your computer.
VideoReader cannot open a video file for reading
on Windows platforms. This might occur if you have installed a third-party
codec that overrides your system settings. Uninstall the codec and try opening
the video file in MATLAB again.
The audio signal in a file represents a series of samples that capture the amplitude of the sound over time. The sample rate is the number of discrete samples taken per second and given in hertz. The precision of the samples, measured by the bit depth (number of bits per sample), depends on the available audio hardware.
MATLAB audio functions read and store single-channel (mono) audio data in
m-by-1 column vector, and stereo data in an
m-by-2 matrix. In either case,
m is the number of samples. For stereo data, the
first column contains the left channel, and the second column contains the right
Typically, each sample is a double-precision value between -1 and 1. In some
cases, particularly when the audio hardware does not support high bit depths,
audio files store the values as 8-bit or 16-bit integers. The range of the
sample values depends on the available number of bits. For example, samples
uint8 values can range from 0 to 255
(28 – 1). The MATLAB
soundsc functions support only
single- or double-precision values between -1 and 1. Other audio functions
support multiple data types, as indicated on the function reference
|Platform Support||File Format|
|All platforms||WAVE (|
|Windows 7 (or later), Macintosh, and Linux||MP3 (|
|MPEG-4 AAC (|
On Windows platforms prior to
audioread does not read WAVE files with MP3 encoded
On Windows 7 (or later) platforms,
audioread might also
read any files supported by Windows
On Linux platforms,
audioread might also read any files
supported by GStreamer.
audioread can extract audio from MPEG-4
.m4v) video files on
Windows 7 or later, Macintosh, and Linux, and from Windows
Media Video (
.wmv) and AVI (
files on Windows 7 (or later) and Linux platforms.