Video quality metric for low bitrate compressed videos

Traditionally, peak signal-to-noise ratio (PSNR) has been used to represent the quality of a compressed video sequence. However, PSNR has been found to correlate poorly with subjective quality ratings, particularly at much lower bit rates and frame rates. This paper proposes an objective video quality metric to automatically measure the perceived quality of a stream of video images based on a combined measure of distortion-invisibility, block-fidelity, and content richness fidelity. The proposed method has been tested on CIF and QCIF video sequences compressed at low bit rates and frame rates and it is shown to give significantly better correlations to human perception than peak signal-to-noise ratio (PSNR).