How do I retreive the data, samples, from a audioplayer object

How do I retrieve the sample data from an audioplayer object. This seems like an obvious thing to allow, but I cannot find any information on it.

Example: AudObj = audioplayer(SoundData, Fs, N);

Now if I don't have access to SoundData, how can I retrieve it from AudObj?

Answer 1

[Wayne King]

I'm not sure what you mean by "you don't have access to SoundData"

What is SoundData?

Normally you feed audioplayer, the data vector from the MATLAB workspace.

Like:

            load handel;
            p = audioplayer(y, Fs);

Or are you passing it a handle from an audiorecorder object?

[Jerry Gregoire]

By SoundData I mean the samples that were used to create the object, (ie) y. So if I am given the object, I can extract y to do analysis. JG

Answer 2

[Matt Tearle]

This seems like an unnecessarily inelegant hack, but you could always attach SoundData as AudObj's UserData property:

load handel;
player = audioplayer(y, Fs);
player.UserData = y;
clear y
y = player.UserData;

If you edit the audioplayer classdef, it appears that the actual audio data is "locked down" as a private property (called AudioData).

[Jerry Gregoire]

Yeah, I thought of this. It is inefficient since the object already has the data. If I have to, I will do it this way. It would be nice though to have access to the data if I didn't create the object.

[Matt Tearle]

I'm not sure it will be that inefficient. MATLAB generally does a lazy copy (just a reference unless the data is modified). Not sure if there's anything about being a private property of the object that changes that behavior.

But, yes, the issue of getting the object from someone/somewhere else is tricky. Not much you can do about that. Maybe you could submit an enhancement request.

Answer 3

[Sean de Wolski]

The audioplayer data is stored in a property that has SetAccess and GetAccess attributes set to private

This can be seen by opening the audioplayer class.

I'll put in the enhancement request.

Answer 4

[Peter Urlings]

To retrieve the data from an audioplayer object use:

s=struct(AudObj)
SoundDataPullout = s.AudioData;

[Petros Oratiou]

Does this mean that making a struct copy of an object will ignore all restrictions?

[Walter Roberson]

@Petros Oratiou

Yes, using struct() can violate access restrictions.