We have seen issues in our IPNC (Appro IPNC DM368 MT5 SDK 4.x) with the RTSP video frame timestamp jumping when the user sets the system clock. In av_capture/framework/csl/kermod/src/ccdc/csl_ccdcInt.c CSL_ccdcVd0Isr timestamps each frame with timestamp = CSL_sysGetCurTime(); which uses do_gettimeofday(), which is the wall-clock time and hence will move around when the time/date and timezone are adjusted.
I tried modifying the call to use clock_gettime(CLOCK_MONOTONIC) or do_posix_clock_monotonic_gettime(); but this appears not to give a monotonic clock (it will move backwards if system time is adjusted backwards).
Can anyone suggest a function/call within the IPNC SDK that will give a properly monotonic non-skipping clock source for us to timestamp frames?