<?php
$input = "www.soundcloud.com/username/songtitle/s-qciX1vDI2Cq";
$output = preg_replace("/^(?:https?:\/\/|)(?:www|m)\.(soundcloud\.com\/[^\/]+\/[^\/]+)(?:\/.*?|)$/", "http://$1", $input);
print "$output\n";
PD9waHAKCiRpbnB1dCAgPSAid3d3LnNvdW5kY2xvdWQuY29tL3VzZXJuYW1lL3Nvbmd0aXRsZS9zLXFjaVgxdkRJMkNxIjsKJG91dHB1dCA9IHByZWdfcmVwbGFjZSgiL14oPzpodHRwcz86XC9cL3wpKD86d3d3fG0pXC4oc291bmRjbG91ZFwuY29tXC9bXlwvXStcL1teXC9dKykoPzpcLy4qP3wpJC8iLCAiaHR0cDovLyQxIiwgJGlucHV0KTsKCnByaW50ICIkb3V0cHV0XG4iOw==