1. A method of controlling a video content system based on an input video sequence and a corresponding degraded video sequence, the input video sequence including at least a current input frame and a preceding input frame, and the degraded video sequence including at least a current degraded frame and a preceding degraded frame, the method comprising obtaining the current input frame, the preceding input frame, the current degraded frame and the preceding degraded frame; computing a first differences value from the current input and the preceding input frames and a second differences value from the current degraded frame and the preceding degraded frame; comparing the first and second differences values giving rise to an inter-frame quality score; computing an intra-frame quality score using an intra-frame quality measure that is applied in the pixel-domain of the current degraded frame and the current input frame; and providing a configuration instruction to the video content system based on a quality criterion related to the inter-frame and the intra-frame quality scores.