a few words about web development

How to generate waveform from audio file?

Waveform images done the easy way
In this example we are going to use a free REST API:

$url = 'http://my_server.com/song.mp3'; //you can also send m4a, flac, wav and wma
$data = json_decode(file_get_contents('http://api.rest7.com/v1/sound_waveform.php?url=' . $url));

if (@$data->success !== 1)
    $image = file_get_contents($data->file);
    file_put_contents('waveform.png', $image);

The script will generate for a 4 minute song something similar to this image:
The background is transparent and only color used is black (for the waveform).