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

JCTVC-M0146 VUI extension and SEI for chroma sampling filter [T. Chujoh (Tosiba), K. Kazui (Fujitsu Lab.), P. Topiwala, W. Dai, M. Krishnan (FastVDO LCC.)]

Chaired by J. Boyce.

Since chroma formats that are called 4:2:0, 4:2:2 and 4:4:4 are used at the video coding technology, some kinds of chroma format conversions are needed when output video is translated or displayed. Although the sample location of chroma format can be specified at VUI in current draft specification, there is no information regarding chroma sampling filter. This contribution provides a framework to send recommended up-sampling and down-sampling filter coefficients for chroma format conversion by using VUI and SEI message. Especially, it is possible to solve a problem of error accumulation when chroma conversions are repeated.

Proposed method includes a new VUI syntax elements in an SPS extension and an SEI message. If the VUI specifies a user-defined filter, the SEI message is used to carry the user-defined filter coefficients.

It was questioned why a specific entry in the VUI table was proposed for a particular filter that is not specified in any standard, and not just using a user defined entry.

An alternative would be to use only an SEI message instead of a hybrid solution between a VUI and an SEI message.

The contribution does not contain information about the normalization stage.

For further study.

JCTVC-M0281 Additional experiment results for frame packing arrangement SEI message for 4:4:4 content in 4:2:0 bitstreams [Y. Zhang, Y. Wu, S. Kanumuri, S. Sadhwani, G. J. Sullivan, H. S. Malvar (Microsoft)]

Chaired by J. Boyce.

M0229 is somewhat related to this.

This contribution proposes a method to extend the use of the frame packing arrangement SEI message to represent 4:4:4 content in nominally 4:2:0 bitstreams. The contribution is an update of the prior contributions JCTVC-K0240 and JCTVC-L0316 that provides additional experiment results. With the proposed method, it is reported that one constituent frame (e.g. in a top-bottom packing or alternating-frame coding scheme) can be decoded compatibly as an ordinary 4:2:0 image, or can be supplemented with the data from another constituent frame to form a complete 4:4:4 image representation. It is proposed to include support for the additional scheme into the frame packing arrangement SEI message in both AVC and HEVC, to facilitate deployment of systems using this method. Since 4:2:0 is the most widely supported format in products, it is asserted that having an effective way of conveying 4:4:4 content through such decoders can provide the substantial benefit of enabling widespread near-term deployment of 4:4:4 capabilities (especially for screen content coding). The proposed method operates by packing the samples of a 4:4:4 frame into two 4:2:0 frames and encoding the two 4:2:0 frames as the constituent frames of a frame packing arrangement. The semantics of 'content_interpretation_type' are extended to signal this packing arrangement. The proposed scheme is asserted to be of high practical value for applications involving screen content. Relative to native 4:4:4 encoding, the proposed scheme can provide the advantage of compatibility with the ordinary 4:2:0 decoding process that is expected to be more widely supported in decoding products.

Proposes to use the frame packing SEI message for a different purpose than stereo support. Proposed for both HEVC and AVC.

Experimental results provided using the screen coding coding content, and also a comparison with the RExt 4:4:4 encoder, although it is noted that this contribution is specifically aimed at providing 4:4:4 when a 4:4:4 codec is not supported. Provides a limited form of chroma format scalability using a main profile decoder.

Images are provided which illustrate some visual quality improvements vs. 4:2:0 coding. A question raised about at what bitrate the proposed method outperforms 4:2:0 coding.

Proposes a signalling method to provide chroma upsampling filter information.

3 new content interpretation types proposed. Downsampling filtering operation for each type is provided, using simple filters.

The cContribution does not address interlaced sources.

Text was provided, but without figures in the text, which would be useful.

For further study. Request to have software and/or processed video sequences provided.

JCTVC-M0126 Spatial substream definition [M. Arena (RAI), P. Sunna (RAI), G. Ballocca (Sisvel Technology)]

Withdrawn.