CABSscore
A definite video codec metric
Read CABScore spec here: CABSscore specification
Create your own CABSscores with codecbench
From the abstract:
Measuring video codec performance has traditionally been a simple matter. One selects an encoder and runs a sequence set through it producing the resulting compressed bitstreams. Subsequent comparisons of the size of the resulting bitstream against some chosen metric (SSIM, PSNR, ...) yields the framework for comparison of performance between different setups. While this is a valid proposition some problems are inherent with it. The lack of standardization between benchmarking setups makes their results not comparable and therefore relative. This paper introduces the CABSscore (Codec Average Bitrate Savings) which provides a definite, clearly stated framework to the benchmarking environment.