Of itu-t sg16 wp3 and iso/iec jtc1/SC29/WG11

JCTVC-O0013 JCT-VC AHG report: SHVC inter-layer filtering (AHG13) [E. Alshina, J. Chen, J. Dong, A. Segall, P. Topiwala]

There have not been discussions related to the mandates of this ad-hoc group over the reflector between the 13th JCT-VC meeting and the 14th JCT-VC meeting. However, there was significant activity in the area within the SCE1 and SCE3 core experiments.

Two versions of down-samplers with different spectral characteristics (so-called SHVC and JSVM down-samplers) were provided by Qualcomm for SCE1 experiments.

Test sequences down-sampled with non ×1.5 and ×2.0 ratios were generated and shared by Samsung. Specific spatial ratio (~×1.75) was selected to exploit more or less equally intensively re-sampling filters with all 16 phases. These sequences were used in SCE1 tests for identification the best re-sampling filter design for arbitrary spatial ratio scalability support.

The performance of two scalable systems with different down-samplers was studied as part of AhG13 activity. Corresponding contribution is submitted to this meeting. So-called SHVC down-sampler was found to be better for all-intra, random access and low-delay-B configurations.

This was discussed during the AHG report presentation, and assurances were given regarding the subjective quality, sharpness, and lack of excessive aliasing in the proposed SHVC down-sampler.

“SHVC downsampler has better performance than JSVM” – there was some discussion whether this statement would be true under all circumstances, e.g. with usage of rate control.

Several experts emphasized that the JSVM downsampler has higher frequency cut-off, and subjective viewing had been performed earlier unveiling better subjective performance at base layer.

An effect of accurately taking into account chroma position alignment during re-sampling processing was studied. There is one contribution on this issue.

One more contribution which re-open the discussion about taking into account displacement between base and enhancement pictures was submitted to this meeting.

There is one non-SCE contribution which proposed modification of SHVC re-sampling process.

In SCE3 and non-SCE3 contribution 2 different inter-layer filters which are applied additionally to re-sampling were studied.

Relevant contributions were listed.