International organisation for standardisation organisation internationale de normalisation

Other SEI and VUI (7)

14.1.97.1.1.1.1.1.343JCTVC-P0081 Comments on chroma_resampling_filter_hint SEI [C. Fogg (Harmonic)]

This contribution suggests a few clarifications on chroma_filter_hint SEI semantics that is intended for indicating chroma subsampling filters in cascaded encoding within studio exchange: 1) the intended precision of the operation; 2) intended use of the SEI. It was also requested to consider whether the syntax should have the ability to signal an explicit phase offset for the chroma channels so that MPEG-1 and JPEG-style horizontal chroma subsample siting can be unambiguously conveyed. It was also recommended to carry over what is asserted to be a key note from the SMPTE RP.2050 spec. into the chroma_filter_hint SEI semantics section clarifying that "... there is no benefit to using the filter sets defined in this document in an application when the output is not re-encoded." It was suggested to also be useful to add an a note that the SEI is not intended to support device-independent output chroma resampling should JCT wish to inform readers of the possibility that decoders are unlikely to implement a programmable chroma resampling engine, especially in the light that display processors may combine the chroma 4:2:0 upsampling step with other scaling, and that HDMI 2.0 et al that are now capable of passing through 4:2:0 from the HEVC decoded picture buffers directly to an external display processor.

(The phase offset issue may be adequately addressed by the VUI chroma siting indicator per Annex E.)

Decision: Intended primarily as editorial input; delegated to the editors for consideration.

14.1.97.1.1.1.1.1.344JCTVC-P0120 AHG9: Display hint SEI message for ROI layers [K. Ugur, M. M. Hannuksela (Nokia)] [late]

See BoG report P0290 and related notes.

14.1.97.1.1.1.1.1.345JCTVC-P0123 RExt HLS (AHG5 and 9): SEI message for alpha channel information [M. Naccari, M. Mrak (BBC)]

See BoG report P0290 and related notes.

14.1.97.1.1.1.1.1.346JCTVC-P0131 MV-HEVC/SHVC HLS: Layer up-switching information SEI message [A.K. Ramasubramonian, Hendry, Y.-K. Wang (Qualcomm)]

See BoG report P0290 and related notes.

14.1.97.1.1.1.1.1.347JCTVC-P0133 MV-HEVC/SHVC HLS: On recovery point and region refresh SEI messages [Hendry, Y.-K. Wang, A. K. Ramasubramonian (Qualcomm)]

See BoG report P0290 and related notes.

14.1.97.1.1.1.1.1.348JCTVC-P0204 MV-HEVC/SHVC HLS: Sub-bitstream property SEI message [Y. Chen, Y.-K. Wang, A. K. Ramasubramonian, Hendry (Qualcomm)]

See BoG report P0290 and related notes.

14.1.97.1.1.1.1.1.349JCTVC-P0261 Extension of the pic_struct element in HEVC [A. Tourapis, D. Singer, K. Kolarov, S. Saunders (Apple)] [late]

Discussed 01-16 (GJS).

In this contribution, an extension of the pic_struct element that is present in the picture timing SEI message of HEVC is proposed. This extension is asserted to enable carriage of interlaced video material using a "progressive-like" carriage mechanism that does not require any other coding tool modifications in the specification.

The proponent indicated that they were proposing this to help fulfil the needs of others rather than as something they planned to use themselves.

It was noted that this is related to P0083. It was suggested that, if adopted, we should consider whether it should be done as a new SEI message rather than as use of reserved type codes. Some interest was expressed. Further study was encouraged.

6.