id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
287	Fast encoder search for MTS defect	chollmann		"For MTS there is an additional command line parameter MTSIntraMaxCand which is used to limit the number of completely evaluated MTS transform candidates. This worked fine in VTM-4.
In VTM-5, however, this part is broken. Setting the parameter to 1, 2, 4 and 5 (3 is CTC) gives identical results for both bit rate and PSNR. Only setting it to 0 shows some loss (but significantly less than expected as this should resemble the case where MTS = 0).

There seems to be a connection to the implementation of the LFNST, as with LFNST enabled the ''trModes'' vector which is passed to the ''transformNxN'' function in line 2538 of IntraSearch.cpp never seems to contain more than two modes - (DCT2, DCT2) and TransformSkip. This vector should include the MTS modes (between DST7 and DCT8) as well. 

A further test shows that when LFNST is disabled, MTSIntraMaxCand works as expected (different run times, different results).

Maybe those who implemented LFNST can help with the bug fix."	defect	closed	minor		VTM	VTM-5.0	fixed	MTS, LFNST	ksuehring XiangLi fbossen jvet@…