JVET-AE0180 On ECM SW memory consumption [R. Chernyak, S. Liu (Tencent), Y. Yasugi, T. Ikai (Sharp)]

This document provides an ECM SW memory consumption analysis. It also proposes a straightforward non-normative ECM SW modification that losslessly reduces ECM memory consumption worst case for about 2 GiB under CTC.

It was found that larger memory is consumed by covariance matrices in ALF, and memory allocation for wraparound MC, even if the latter is not used in the ECM CTC.

It was commented that this is a step in the right direction, but much more effort would be necessary for reduction of memory consumption. It was further suggested that it would be good if proponents would be enforced to report (in the excel sheet) the additional memory consumption of the proposal.

One expert commented that covariance matrices consume a maximum which is lower than reported here.

It was commented that a similar analysis for decoder would also be useful.

Decision (SW): Adopt the change of unnecessary memory allocation for wraparound MC in cases where the tool is disabled (for ECM, and to the discretion of SW coordinators to also be implemented in VTM and NNVC).

It was further agreed that reporting the additional memory usage of a new element proposed will be made mandatory (e.g., by adding a corresponding column to the excel sheet). It is understood that this is purely informative and not meant as a mechanism to reject a proposal, but rather identify newly added elements that cause excessive additional memory consumption, such that a solution for possible reduction can be sought by a coordinated activity between proponents and software coordinators.

This should be the “VmPeak” memory consumption output from ECM.

It should also be reported in cross-checks.

It was commented that a similar output for the decoder would be desirable, which would require an implementation in the ECM.