obd slightly out of sync from video

I've mentioned this in the past (cannot find the thread/post) on my old phone (HTC10) where the obd data was lagging behind the video/sound stream.
I've since replaced the phone with a 2017 Samsung A3 and looking back at last years event also doing the same.

the session on the HTC10 i sent to aol and he fixed it and i think he stated that some devices just have an issue with it.

i also use the garmin glo 10hz gps reciever.

Is there any reliance on device times? reason i ask is my A3 phone claims to be very slightly out of sync (https://time.is/ says i'm 0.4secs slow) and 0.4sec is roughly the delay between video&obd overlay info. It uses network time sync but not rooted so i cant use the various adb/root play store apps to sync the phone via ntp to prove it.

It's most noticeable with throttle position vs audio. can hear the engine revs drop but throttle position still reports 100%.
also looks like the gps speed is also delayed. similar test; listen to audio and watch the analysis data lines lag behind the video.

seems like the obd&gps lag behind the video slightly.

the HTC10 would've been on 6.0/late 5.x release as i replaced it around july/aug last year. a3 is on v6.1b so i can use custom PIDs.

Comments

  • aolaol
    edited February 20
    Hi,

    - The automatic video sync might be slightly off, against GPS data (or any other data). There's no way to make it millisecond accurate as there's various different delays to compensate. You can already adjust it here: https://racechrono.com/article/480 . I usually adjust the video sync according to OBD-II data, as you can do it by ear against RPM.

    - There's also usually small delay between GPS and OBD-II data. It's caused by a build-in delay on GPS chips, and it varies from device to device. There is an update coming to next major release, to allow adjusting the data sync between data from different devices.

    - The device time is unrelated, as RaceChrono uses GPS time for almost everything.

    The current official version is v6.2.1, and it already includes all the custom PID features, with some bug fixes.

  • thanks for clarifying. i'll take a look into all that and revert my version from 6.1beta last year to the latest stable.
  • aolaol
    edited February 22
    Actually it's upgrading rather than reverting... It should update from Play Store. Maybe you have set manual updates?
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