The Joint Collaborative Team on Video Coding (jct-vc) of itu-t wp3/16 and iso/iec jtc 1/ sc 29/ wg 11 held its tenth meeting during 11-20 July 2012 at the City Conference Centre (ccc), a k. a

JCTVC-J0555 Mental cross-check of Additional sample_ratio_idc values for square samples (JCTVC-J0287) [Lowell Winger (??)] [late]

5.12.9.2Frame packing arrangement (FPA) SEI message and related (4)

JCTVC-J0070 2D compatible frame packing arrangement SEI [O. Nakagami, T. Suzuki (Sony)]

In the 9^th Geneva meeting, 2D compatibility of frame compatible stereo 3D coding was discussed. JCTVC-I0058 and JCTVC-I0072 suggested using cropping and SAR syntax with frame packing arrangement SEI (FPA_SEI) for the purpose. One issue raised there was inconsistency between the cropping syntax and the current FPA_SEI definition. It was discussed that one solution was to change the definition of FPA_SEI in HEVC, apart from AVC.

This contribution proposes to define a SEI for the 2D compatibility as a subset of FPA_SEI. The motivation is not to create confusion in the market by changing the FPA_SEI behavior in HEVC. The proposed SEI is named as 2D compatible frame packing arrangement SEI (2Dcomp_FPA_SEI). The differences from FPA_SEI are 1) timing to be applied, 2) syntax removal for some packing types and 3) syntax addition for view position. It is asserted that the proposed SEI is consistent with the cropping scheme for the 2D compatibility.

This contribution suggests that “the SEI message informs the decoder to not perform the cropping”, where however due to the description of cropping in SPS it would be normative. It would be a contradiction if an SEI message which does not usually imply normative decoder behaviour would do that.

Options:

• 
  Put cropping to VUI – in that case 2D decoders may exist which ignore it – not desirable.
  
• 
  Describe cropping as normative unless an SEI message is known to the decoder which makes use of the non-cropped area.
  
• 
  Define a second cropping window only for the second view in context of the SEI message, where only the first (“base view”) cropping window decoding belongs to the conformant part (to be decoded by both 2D and 3D devices), but any decoder targeting 3D would usually decode the second window as well.
  

See further notes in discussion of J0247.