Yeah, that sucks. Did the camera send SEI Picture Timing messages? RTCP Sender Reports with NTP timestamps? Either could potentially help matters if they're tr

Yeah, that sucks. Did the camera send SEI Picture Timing messages? RTCP Sender Reports with NTP timestamps? Either could potentially help matters if they're trustworthy. I haven't encountered that exact problem (large fixed offset between the streams), but I agree in general these cameras' time support is poor and synchronizing streams (either between main/sub of a single camera or across cameras) is a pain point. Here's what my software is doing today: https://github.com/scottlamb/moonfire-nvr/blob/master/design/time.md https://github.com/scottlamb/moonfire-nvr/blob/master/design... Any of several changes to the camera would improve matters a lot: * using temporal/spatial/quality SVC (Scalable Video Coding) so you can get everything you need from a single video stream * exposing timestamps relative to the camera's uptime (CLOCK_MONOTONIC) somehow (not sure where you'd cram this into a RTSP session) along with some random boot id * allow fetching both the main and sub video streams in a single RTSP session * reliably slewing the clock like a "real" NTP client rather than stepping with SNTP but I'm not exactly in a position to make suggestions that the camera manufacturers jump to implement...