N17039, Defect Report on ISO/IEC 14496-10:2014/Amd.2

It has been reported that there is an error in the AVC text specification for the recently added levels 6, 6.1, and 6.2 (which were added to support very large picture sizes such as “8K” pictures). The problem is that the current specification requires the decoder to support a 17-bit range of motion vector deltas, which is suggested to be an oversight and is reportedly not supported in the JM reference software. It is planned that corrective action will be taken to limit the range to 16 bits when feasible. Another (less significant) issue has also been noted in regard to computation of absMvdCompN. For the latter case, there is no technical error in the standard, but it may be appropriate to highlight an issue with the dynamic range of this variable, to assist implementers in avoiding implementation problems.