How to get the audio signal from a video

I have a video, i needed to get the audio signal from the video...

I did as,

a = audioread('audio1.avi');

in some cases i can read the audio, but in some cases it is showing error such as

Error using audioread (line 88)
The file type is not supported

Error in demo_audio (line 5)
a = audioread('audio1.avi');

In some videos it shows the error as

Error using audioread (line 88)
Failed to initialize internal resources.

Error in demo_audio_extract (line 9)
input_file = audioread('audio1.avi');

Is there any other way to get the audio signal from a video... why does this error occur?

Answer 1

[KSSV]

A quick googling leads to the following links:

https://in.mathworks.com/matlabcentral/newsreader/view_thread/291514

http://in.mathworks.com/matlabcentral/newsreader/view_thread/302147

[Elysi Cochin]

Sir i had tried that also,

fileInput = 'inputVideo.avi';
fileOutput = 'outputAudio.wav';
hmfr = video.MultimediaFileReader(fileInput, 'AudioOutputPort', true, 'VideoOutputPort', false);
hmfw = video.MultimediaFileWriter(fileOutput, 'AudioInputPort', true, 'FileFormat', 'WAV');

The error i got was as

Undefined variable "video" or class "video.MultimediaFileReader".

Error in demo_audio_extract (line 3)
hmfr = video.MultimediaFileReader(fileInput, 'AudioOutputPort', true, 'VideoOutputPort',
false);

[KSSV]

You are supposed to have some toolbox mentioned in the link. You have seen that?

[Elysi Cochin]

They say "As of release R2011a, this product was renamed Computer Vision System Toolbox"...

I have "Computer Vision System Toolbox", so how to edit the codes accordingly...