Accessing music samples?

[notshaggy]

Is there a way to access the samples of a music?

I'm trying to create an audio visualiser using FFTW, so think I need the audio samples to give as input?

Thanks for any help.

[dabbertorres]

http://www.sfml-dev.org/documentation/2.2/classsf_1_1SoundBuffer.php#a4ba0c1e5b5be500af42de30b1360eb2e

[notshaggy]

Thanks for pointing that out!

However it always gives me the same values when I print out the array, so I'm not really sure if I'm calling it correctly?

[Nexus]

What do you expect? Should they magically change?

[notshaggy]

I would have expected the samples to have different values as the music is played, yes.

Surely if the samples are the same then the sound played would be one continuous tone?

[Nexus]

No, sf::SoundBuffer stores all the samples of an audio file, it does not stream continuously. As such, the samples only change when you reload them.

[Laurent]

If you want to process the samples of a playing sf::Music on the fly, then create your own class derived from it, and override the onGetData virtual function. Something like:

class MyMusic : public sf::Music
{
protected:

    bool onGetData(Chunk& data) override
    {
        if (sf::Music::onGetData(data))
        {
            // ... data contains the next chunk of samples to be played by the music ...
            return true;
        }
        else
            return false;
    }
};

Since sf::Music is triple-buffered, the data that you get there will only be played a few moments later (something like 2 seconds), so you may have to adjust if you want your visualizer to be perfectly synchronized with the music.

[notshaggy]

Thanks for everyone's help so far.

I tried doing it as above with better results. Is there a way to get onGetData() to run more frequently?

[Laurent]

Nop. It is currently hard-coded in sf::Music (buffer length) and sf::SoundStream (buffer count).