Matched Quality Evaluation of Temporally Downsampled Videos with Non-Integer Factors

Recent research has shown that temporal downsampling of high-frame-rate sequences can be exploited to improve the rate-distortion performance in video coding. However, until now, research only targeted downsampling factors of powers of two, which greatly restricts the potential applicability of temporal downsampling. A major reason is that traditional, objective quality metrics such as peak signal-to-noise ratio or more recent approaches, which try to mimic subjective quality, can only be evaluated between two sequences whose frame rate ratio is an integer value. To relieve this problem, we propose a quality evaluation method that allows calculating the distortion between two sequences whose frame rate ratio is fractional. The proposed method can be applied to any full-reference quality metric.