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

6.3.2Parameter set extension mechanism (3)

General

Discussed Wed 23rd evening (GJS).

Decision: Adopt JCTVC-O0142 (as a structure to be used to switch whatever extensions we define in SPS, not necessarily committing to having these extensions be separate for each extension, but the current plan unless decided otherwise is to use one flag for range extensions syntax presence and one flag for SHVC+MV-HEVC extension syntax presence).

JCTVC-O0142 Conditional SPS extension syntax for RExt, SHVC, and MV-HEVC [J. Boyce (Vidyo)]

Discussed Wed 23rd evening (GJS).

Multiple extensions to HEVC (RExt, MV-HEVC, SHVC) are currently being developed in parallel. It is asserted to be desirable to be able to implement a codec for a particular extension without having to be aware of the other extensions. It is proposed to add flags in the SPS extension to indicate conditional inclusion of SPS extension syntax for particular extensions, so that decoders are not required to parse SPS extension syntax elements related to unsupported extensions. The proposed syntax enables future profile definitions which enable combinations of extension types.

It is also asserted that the recent drafts of the RExt (JCTVC-N1005_v3) and MV-HEVC (JCT3V-E1004) extensions have incompatible SPS extension syntax. The proposed syntax addresses this incompatibility between extensions.

The proposal is to conditionally include syntax elements in the SPS – similar to prior proposal JCTVC-M0045 sub-proposal #4.

It would be undesirable for the (N+1)th extension to be required to parse all syntax that was put in previously by the previous N extensions.

Proposes to send 8 flags, each of which indicates the presence of some syntax elements (where the 8th could be used to nest another 8 later).

Could also be used for a PPS extension if needed.

It was remarked that O0214 is somewhat similar.