Harry's GPS Suite Forum

I have a new and interesting issue with VBO export to report.

Background:
I recorded three sessions totalling 33 laps at about 2:20 a lap the other day. Video is good, data is solid, XGPS150 worked great at 5 Hz, iPhone 4S running iOS 7.1.2. All is perfect with the dataset. I overlaid 18 minutes of video with no issues.

Problem:
I selected the "trackday" option and exported all 33 laps to .VBO via Dropbox, except it wouldn't go - the Dropbox transfer failed three times in a row. So I did it over and exported to email. That worked, but the email attachment was 19 MB and when I unpacked the gz file, the VBO file was 557MB.

Last time out, a week ago, the VBO export via Dropbox worked great and I had 32 laps of data in a 4MB file. It worked fine directly with Circuit Tools. Equipment and track were the same as this time.

[Split from the FAQ as this is a different issue]

For Dropbox, please check if you have a network connection and all Dropbox settings are fine. E.g. try the Dropbox app and make sure you can access your files. I just tested it and it works fine with iOS7.1.2 and the latest Dropbox app.

In case the VBO is not compressed (i.e. arrives with a .vbo, not .vbo.gz prefix), it will have approximately 50kB per 1 minute recording. When compressed, it will have around 14kB per 1 minute recording. The numbers are largely independent from the equipment used as LapTimer generates a stream of 10 Hz data.

While the 4MB make sense (for 4 MB and 32 laps, this means roughly 3 and a half minute per lap), the 557 MB look strange. There is one situation this can happen: in case one of your laps is corrupted (i.e. includes recordings from the day before and the first lap of the day), the 10 Hz generation may generate huge files (image you have two positions 12 hours apart - that is making quite a lot of interpolated positions at 10 Hz). I have seen this type of corruption lately for situation where LapTimer has been finished in the pits without using the Cancel button to quit recording from the cool down lap. I do not find the fix time in my change log currently (strange), but it should be fixed in v18.1 already. Please run a Check Data from Lap List to purge this recording and try again.

- Harry

Thanks, Harry. Running Check Data corrected it and now I have a 4.4MB file that Circuit Tools is happy with. I knew something was wrong, but I'm still a new enough user not to know how to fix it. Export to Dropbox worked fine on the first try too, just as it did last week. I think there was a problem with transferring the huge file to DropBox but now that the file's the right size, it's all ok.

Yes, Dropbox is actually not too good transferring big files into it. I'm sure it can do it, but I found it often extremely slow to come back when sending a file into it.

Harry