% Saves audio data to a wav file before playback.
%
% audio     - audio samples
% fs        - sampling rate (Hz) [default: 8000]
% nbits     - precision (bits) [default: 16]
% wavfile   - filename for the wav file [default: '/tmp/tmp.wav']
%
% usage: play(audio, fs, nbits, wavfile)

function play(audio, fs, nbits, wavfile)

    % parse input arguments or use defaults
    switch(nargin)
        case 1, wavfile='/tmp/tmp.wav'; nbits=16; fs=8000;
        case 2, wavfile='/tmp/tmp.wav'; nbits=16; 
        case 3, wavfile='/tmp/tmp.wav';
        case 4,
        otherwise, error(sprintf('usage: play(audio, 8000, 16, ''/tmp/tmp.wav''\ntype: help play for further details...'));
    end

    % save audio to file, scale prior to writing to avoid clipping
    audio = 0.999*audio/max(abs(audio));
    wavwrite(audio, fs, nbits, wavfile);
    
    % playback the audio
    if(exist(wavfile, 'file'))
        syscmd = sprintf('mplayer %s', wavfile); % uses mplayer for playback
        %syscmd = sprintf('play %s', wavfile);   % uses sox play for playback
        system(syscmd);
    else
        error(sprintf('%s: file not found.', wavfile));
    end

% EOF