id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
1194	Difference in neighbor calculation for SAO in HM-11.1 and HM-12.0	gregory		"Between HM-11.1 and HM-12.0 function setNDBFilterBlockBorderAvailability was renamed to deriveLoopFilterBoundaryAvailibility in a change set 3543. This change set is based on JCTVC-N0230 which is supposed to be an encoder-only enhancement and only a cleanup of decoder code. But the change also changes logic for determining neighbor CTB across slice boundaries for SAO filter in case of above-right and below-left neighborhood, and therefore affects how decoder applies SAO filter to a frame.

Previously value of flag slice_loop_filter_across_slices_enabled_flag was always taken from the later slice in the encoding order. But in HM-12.0 when slices for current and neighbor CTB are different, code compares slice start blocks in raster order. When tiles are enabled, CTB with bigger tile scan address may have a smaller raster scan address, and when values of slice_loop_filter_across_slices_enabled_flag are different, decoder may work differently than in HM-11.1 version.

Attached is a patch that fixes this behavior for decoder and uses tile scan.

If necessary I can attach streams that show that HM-12.x decoder behaves differently from previous versions."	defect	closed	major	HM-13.0	HM	HM-12.0	fixed	sao	fbossen ksuehring davidf jct-vc@…