Video/Data Sync

[Niner1000RR]

Strange issue I am having.

I get that the data logger (AiM SoloDL) and the GoPro (Hero4) may sample/record at different rates and need adjustments. But I would assume that would be a constant measure throughout the timeline.

So I import my video and data, I set it up to sync. I like to use the "shift into 2nd gear" because where I have my GoPro I can see the dash on my bike and can make this sync PERFECTLY!

So I get that done and it looks perfect, but as I get farther into the video it seems to go out of sync. So I go to the end of the video and use the "playback" adjustment and fiddle with it until it's lined up perfectly, which tends to be about .9940 to get that right. So I create the video and watch it back. And the middle is out of sync...

So I go back in and try it again, I cannot get the middle and end to remain both in sync.

If I use the "1st time shifting to 2nd gear" option at the beginning, shouldn't I be able to them go to the end of the video and adjust the playback until they are in line and be done?

What am I screwing up? lol

Thanks in advance!!!

[Weston@HPTuners]

If I use the "1st time shifting to 2nd gear" option at the beginning, shouldn't I be able to them go to the end of the video and adjust the playback until they are in line and be done?

Correct, that is how it should work. Normally, any loss of data/video sync further into the project is just due to a little timing drift between the data and video equipment, and RaceRender's "Play Speed" adjustment is usually the easy solution for those cases, but the symptoms you've described suggest that there may be another issue. My main suspicions would be one of the following possible causes:

1) If the video camera had split the video into several chunks (ie multiple video files), which you had RaceRender join together, then it's possible that there's some timing impact on the video as a result of that. GoPro usually seems to be pretty good, but there are also video decoders and other things involved that could impact this as well, so if each split ends up with a few missing frames or a few extra frames, that might explain what you're experiencing.
. a) If the joined video seems like it's longer or slower than the data, then you might try using the Trim Tool on the start and/or end of each individual video clip to see if you can bring it back into sync that way.
. b) Or, if the joined video seems like it's shorter or faster than the data, then you might try having RaceRender insert a very short "Time Filler" in between the video clips (use the Trim Tool on it to set its length), and see if that helps the sync issue.

2) The synchronization point you chose in the video (ie first shift into 2nd gear) did not match the first time that event appeared to happen in the data file, or the responsiveness of the data that it was based on varied throughout the recording. A quick thing to try would be to synchronize based on a different event, and seeing if the sync issues remain or not.

3) The data file's timing has an issue that creates a drift that moves back and forth. I'm not aware of any current issue like this with AIM, but I have seen a small number of cases like this in the past with other data systems, sometimes just due to a bug in their CSV export.

4) The timing drift between the data or video equipment itself was not a constant amount, and had varied back and forth. This is the least likely, especially with quality hardware such as yours.

[Niner1000RR]

Thanks for the response!

#1 is out, since it is just one video file.

#2 ok, this could be. Except I don't think it's likely the issue because when I set that as the sync point, then play it through, it's PERFECT for a little bit and then seems to stray out of sync.

#3 So hmmmm in this case, maybe exporting it again from the Solo might eliminate the issue? Which I can't in this example because I cleared it... But I have a race from earlier in the day that I haven't tried to do yet. But I will tonight.

#4 Yea that would seem odd.

Ok, let me add to the confusion (on my part) but may be helpful? So last night I went back and messed with it again, I had saved the "project" where I left off, which happened to be completed and created the video. So it was after the process I described above. I set the "sync point" at the "shift into 2nd for the first time" then went to the end and adjusted the playback time until the data was insync with the video. I saved it there. Then last night I opened it, I scrolled it back to the beginning and played it, it was out of sync at the beginning... As if it didn't save my "shift into 2nd for the first time" thing or something...

Thoughts?

I'll be messing with it again tonight.

Thanks again for the reply(ies)!

[Weston@HPTuners]

Ok, let me add to the confusion (on my part) but may be helpful? So last night I went back and messed with it again, I had saved the "project" where I left off, which happened to be completed and created the video. So it was after the process I described above. I set the "sync point" at the "shift into 2nd for the first time" then went to the end and adjusted the playback time until the data was insync with the video. I saved it there. Then last night I opened it, I scrolled it back to the beginning and played it, it was out of sync at the beginning... As if it didn't save my "shift into 2nd for the first time" thing or something...

Thoughts?

Ok, that does make sense then... The adjustment of the playback speed will affect the entire length of that file, effectively skewing any previous synchronization that you had done. Depending on how far into the file that sync point was, and the amount of your speed adjustment, that could either have only a small impact or a large one. Either way, you'll ideally want to re-sync it after making any adjustments to the playback speed.

[Niner1000RR]

Ok, see I was thinking it would "hold" that sync'd position. But it doesn't.

So what's the best way to do this?

I have to pick a playback speed, then sync it, then check it and keep repeating that process? Is there a good spot to start from? lol

Thanks!

[Niner1000RR]

Sorry, I should go back through you documentation, I am doing that now!

[Niner1000RR]

Ok, so reading through the documentation, let me see if I get this?

So you load both your video and data files, check.

You want to start by using the "offset within project" timer to initially get a starting point? Then scroll to the end of the video and use the play speed adjustment until it's in sync at the end. Right?

I just did that and I've got it REALLY close, but when I go back to the beginning to check it, it's off again... Maybe I'm not reading it right. Wouldn't be the first time... LOL

[Niner1000RR]

Ok, I tried that method too... I'm definitely messing something up! lol

So I used the "offset within project" tool to get the beginning of the race to match. PERFECT! By the 2nd lap it starts to get out of sync. So I adjust the "Play Speed" to get it in sync. It works. I get to the end and have to make some more adjustments to get it the match. Got it.

Now I scroll back to the beginning and it's off again!

What the heck.... lol

[Niner1000RR]

Check out this video when you can.

I got the offset at the beginning to get the start of the video to sync really well. But after the first lap it starts to get out of sync. So I adjusted the "Play Speed". As a result the end of the video comes back into sync.

But the middle is WAY off... Thoughts? Am I missing something?

https://youtu.be/Qwq54vTD79c

[Niner1000RR]

No ideas on this huh?