JVET-F0050 AhG8: Dynamic viewport based subjective evaluation of 360-degree video coding under CfE test conditions [P. Hanhart, Y. He, Y. Ye (InterDigital)] [late]
A preliminary Joint Call for Evidence (CfE) on Video Compression with Capability beyond HEVC was issued at the 5th JVET meeting (JVET-E1002). The preliminary CfE covers 360-degree video, among other test cases, and defines the test conditions, e.g., coding configuration, sequences, and bit rates, for the evaluations. For subjective evaluation, it is specified that dynamic viewports will be viewed on ordinary monitors and assessed using the expert viewing protocol (EVP) method (Rec. ITU-R BT.2095-0). This document reports results of a subjective evaluation comparing dynamic viewports as defined in JVET-E1030 rendered from 360-degree video sequences encoded with HM-16.15 and JEM-5.0.1 in the equirectangular projection (ERP) format under CfE test conditions. The EVP method was used to assess the compression efficiency of the HM and JEM. The results reportedly showed that the JEM achieves some visual quality improvements over the HM at low and middle bit rates. Finally, based on observations made during the experiment, this document discusses issues regarding the use of the EVP method.
Due to the fact that already the original has impairments (stitching artefacts), additional training is necessary to only judge coding artefacts
The results indicate that for most cases the rate definitions are appropriate.
Further action requested during the meeting was to:
- Investigate the coded results with Vittorio Baroncini
- Perform a further (informal) viewing session to finally decide the rate points for the CfE. These were requested to be selected in a way that for the lowest rate, HEVC starts becoming poor quality, and for the highest rate point HEVC is not yet transparent.
- In case when we come to the opinion that certain rate points need to be aligned, additional results are available with a fixed QP