Slight sounds when braking Yaris

I just started hearing a slight "popping" sound when I apply brakes to my 2012 Yaris. The manual doesn't say what sound to expect when the linings are getting low. Anyone with a Yaris heard a similar sound?

Unless Yaris is different from other Toyotas, the sound you hear when the pads are getting thin is a really loud obnoxious squeal.