Here are some photos that could make any lecturer's heart melt. SKM4212 (Audio Video Digitization) is not known to be an easy subject. The concepts of digital audio, in particular, is challenging to digest, at best.Students typically struggle as they could not for the life of them visualize what is going on with these sound signals. Last lesson was particularly tough, when the concepts of Waveform, Spectrum and Spectrogram were discussed. However, towards the end of the lesson, this was spotted.