Sequence order issue - 2 steps forward, one step backwards

Uploading sequences from a GoPro 5 Black. Sequence uploaded with the desktop Mapillary Uploader app. Example sequence…

https://www.mapillary.com/app/?pKey=654224036290387

If you step through that sequence (or hit the play button) you will see it jump two images forward and then one image back often throughout the sequence. It’s like it’d doing the Texas Two Step or something. I can’t see anything in the file names or EXIF data the looks wrong. Anybody seen this before or have any ideas?

I had something similar with my Garmin Virb XE

I see that. Perhaps a significant difference between my sequence and yours… You can see the jumping back and forth in the lines connecting the points in your sequence. In my sequence - on the other hand - everything looks normal. What caused your sequence to be laid like that IDK. On mine each point is where it should be in the sequence and the connecting lines look right. It’s just that stepping through - or playing - the sequence doesn’t work right (you get the Texas Two Step action).

I know, mine looks more like the procession of Echternach.

It looks like an issue with the EXIF timestamp (capture time).

Can you reproduce the issue with Release v0.9.4 · mapillary/mapillary_tools · GitHub

If you could, would be great to share mapillary_image_description.json here.

Done. Ran it with version 0.9.4. No duplicate detection was commanded. Just…

mapillary_tools-0.9.4-win-64bit process “E:\GoPro Capture\100722 - Original\104GOPRO” --interpolate_directions

… because I’m assuming that’s all the desktop Mapillary Uploader app would have done and I used the desktop app to upload this sequence.

Apparently you can’t attach a file to a post on this forum? Plan B - you can access it here…

https://drive.google.com/file/d/1fWK3ZZujVJKFP5rPOPvxEaVk4k5ZuZXM/view?usp=sharing

One additional thing I noticed… The issue only seems to occur when using the back/play/forward controls at the top of the page. The controls on the road seem to step through the sequence correctly.

Also should note… I sent an email to support for this issue. I got a response back and a response number (23323) from Navjyot Sandhu. In my reply I also provided him all the original images of the sequence which you can find here…

https://drive.google.com/file/d/1l6OQILDoNpiCR49m-FVq6xpGEpgp3f2o/view?usp=sharing

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Thanks. It’s because the image timestamps have no sub-seconds (milliseconds) stored. Here is an sample:

❯ exiftool -time:all 104GOPRO/G0017329.JPG

Date/Time Original              : 2022:10:07 13:13:13
Create Date                     : 2022:10:07 13:13:13
GPS Time Stamp                  : 17:13:11
GPS Date Stamp                  : 2022:10:07
GPS Date/Time                   : 2022:10:07 17:13:11Z

❯ exiftool -time:all 104GOPRO/G0017330.JPG
Date/Time Original              : 2022:10:07 13:13:13
Create Date                     : 2022:10:07 13:13:13
GPS Time Stamp                  : 17:13:11
GPS Date Stamp                  : 2022:10:07
GPS Date/Time                   : 2022:10:07 17:13:11Z

As you can see both images have the same timestamp. The Web player does not know which one it should step first.

In this case, we can interpolate sub-seconds to make sure they are sorted as expected. Will fix it at mapillary_tools side.

One obvious solution that would probably work most of the time would be to sort/index the sequence first by timestamp and then by image name. Most cameras (all that I have worked with) name the images sequentially.

If you are fixing this in mapillary_tools, does that mean that sequences that are already uploaded won’t be fixed? I use the Windows mapillary uploader. Will it be fixed there?

One obvious solution that would probably work most of the time would be to sort/index the sequence first by timestamp and then by image name. Most cameras (all that I have worked with) name the images sequentially.

It makes sense. However, most images might not have the “filename” information for sorting, also it takes some backend effort.

If you are fixing this in mapillary_tools, does that mean that sequences that are already uploaded won’t be fixed? I use the Windows mapillary uploader. Will it be fixed there?

Yes DU uses mapillary_tools underneath, so it will be fixed too.

I get this behaviour regularly from BlackVue mp4 direct uploads. ie just press the play button in the GUI and it is nice and smooth for maybe 30 images, then jerks back one before continuing. I just assumed it was a browser quirk or temporary loss of stream.