Overlay data out of sync with video (iPhone 7)

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Camisade
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Overlay data out of sync with video (iPhone 7)

Post by Camisade »

During my last few track track events, I've noticed the overlay data getting further and further out of sync with the video captured using my iPhone 7 and Harry's LapTime GrandPrix Edition v21.0.7 (and the prior version, since it updated recently). At first the data overlay was only a second or two behind the video action. But in this video, captured at Mid-Ohio Sports Car Course yesterday, August 28th, 2017 with the most recent version of LapTime, you can see that the overlay data is a good 5-6 seconds behind the actual action in the video (check out the G-force meter, for instance).

https://www.youtube.com/watch?v=Kvt3FkB ... e=youtu.be

Is there some way to recalibrate the app, so that it's correctly matching the data to the timestamp of the video frame? For further diagnosis, when I generate overlay for the first laps of the day, the overlay synchronization is pretty close to being right on, but as the day progresses, the overlay gets more and more behind. The above laps took place at the end of the day, and the overlay is WAY off.
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Harry
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Re: Overlay data out of sync with video (iPhone 7)

Post by Harry »

I cannot think of any reason you should get data 5 to 6 seconds behind. The other way around - possible if the cam requires a lot of time to startup (e.g. if the OS is overloaded or you have a huge amount of media on your phone). Please check your Overlay Synchronization / Video setting. The default is 1s.

- Harry
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Camisade
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Re: Overlay data out of sync with video (iPhone 7)

Post by Camisade »

The Overlay Synchronization / Video setting had been left at the default 1s. I have not changed any of those advanced settings. I have gone through and deleted a lot of my old Harry's video that I no longer needed, and done some database maintenance (there were several hundred errors found and fixed). I guess we'll see next time if that makes a difference.
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vladlev
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Re: Overlay data out of sync with video (iPhone 7)

Post by vladlev »

I am experiencing a similar issue with videos captured on iPhone 6 (using the latest version 21.0.11). If i attempt to create the overlay with default settings, my main video (captured by iPhone camera) runs about 2 seconds ahead of data. I tried to adjust the lap start time in "Video details" by using the visual references with no apparent results. However, when I repeated the same process by setting the lap start time stamp exactly two seconds earlier than indicated, I got the lap starting position right on target, but the end of the lap is now 2 seconds off of where it should be. There is an apparent issues where internal videos and data captured by iPhone either start out of sync or are going out of sync as the overlaid video is being exported. As an illustration to the issue described above please see https://youtu.be/T91uRYWIP1I

I also would like to mention that this issue seem to be affecting only videos captured by iPhone camera, the external GoPro recordings are perfectly in sync with data when the overlaid video is created with all default settings. As example, see this video where I cross start/finish line while the overlay timing still shows 2 seconds to go, and both PIP video and data overlay is delayed by two seconds but remain perfectly in sync with each other: https://youtu.be/L6XOL-oBqtc
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Harry
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Re: Overlay data out of sync with video (iPhone 7)

Post by Harry »

Both the startup of internal and external cam recordings suffer from run-time effects that cannot be compensated automatically. At least not easily and without analyzing the content of the video. A delay of 2 seconds however is beyond anything I have seen - at least for automatic (triggered) recordings. Are you sure you have standard delays set?

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