Our TVNZ OnDemand app uses a technique called 'adaptive bitrate streaming'.
This means it works by detecting your available connection speed and device capabilities and then selects a picture quality that best matches these at that very moment. Clever eh?
If your available connection speed changes while video is being played out, the picture quality will adjust as required. This results in very minor freezing of video, fast start time and ultimately the best viewing experience possible regardless of your device or connection speed. Hope that translation helped!