The results and an extensive analysis of the formal subjective verification tests of the H.265/HEVC video compression standard are published in the IEEE Transactions on Circuits and Systems for Video Technology (TCSVT), January 2016. focused on evaluations of UHD content and definition of analytics as part of standardisation process and presented in this paper. The full text of the paper can be accessed .
The tests confirmed the significant compression efficiency improvements achieved in HEVC, verifying the results previously reported using objective quality metrics (PSNR based methods). In fact the compression gains of HEVC compared to AVC were noted to be significantly higher when the subjective metrics (Mean Opinion Scores – MOS) were considered compared to the same considering objective metrics (PSNR). The overall average bit rate saving achieved by HEVC compared to AVC for the same subjective quality was found to be 59% as supposed to the 44% gain shown with objective quality metrics. It was also noted that the bit rate savings for larger picture sizes were higher than smaller picture sizes, which is a very encouraging sign for future UHD deployments.
Detailed results of this subjective experiment are published in , including an extensive set of statistical analyses to help interpret the observations, including the variations in compression performance in distinct test categories. For example, a student’s t-test was used to show that in 92.5% of the test cases, HEVC achieved a comparable or better subjective quality at half the bit rate of AVC.
Detailed introductions to the video quality evaluation methods and statistical analysis methods are also included in the paper to help in appreciating the full extent of the analysis of results.
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