Nextbase 312GW Dashcam and Mapillary

Contributing and equipment
1

Hi, all.

I’m a keen open source mapper, and currently use my Android Nexus 5X to record images, as I drive along. I’m thinking of getting a Nextbase 312GW dashcam, and was wondering if I could make use of this, for Mapillary. Has anyone done something similar? Googling didn’t find anything.

Many thanks,

Chris.

2

Can you get rid of the timestamp ?

3

Not sure, I haven’t bought the cam, yet. It has wifi, so I was hoping a direct upload might be possible, somehow.

Thanks,

Chris.

4

No way, Mapillary is iPhone only.
And read the manual before buying.

5

@ filipc: I have Mapillary on Android.

6

Wouldn’t a 360 camera be better than a bunch of video?

Does the camera write over old data automatically?

7

I’m using a dashcam as a source for pictures. I can’t say anything about the one you’re interested in, but I have an iTracker GS6000-A7 and it works fine! I’ll write down what I do to upload the dashcam pictures:

To upload from the dashcam, I take out the SD Card and put it in my PC and transfer all files onto it. Then I open a program called RegistratorViewer 6.0 (from iTracker homepage) which lets me display and extract the GPS route for specific videos as a GPX file. Also, since dashcams usually record in 3 or 5 minute intervals, it collects all videos from one route to give an overview. For example, if videos 0007 to 0011 are one route, I take these five video files into a separate folder (personal decision to keep things clean) and extract the GPX file into that folder too.
Now comes the more inconvenient part: I take my video editing program, import all five .MOV videos from the folder and save it as a new video: 0007-0011.MP4. The conversion from MOV to MP4 can’t be avoided unfortunately, as Mapillary only takes MP4 videos. But this doesn’t take too much time, it’s just an inconvenient extra step. If your dashcam records in MP4, this can be skipped of course. But I still think you’d have to bring all single video files of one route together as one video, as the GPX file is per route, not per video (meaning you have a GPX location file for 30 minutes of driving but 6 video files each of 5 minutes length)
When that’s done, I upload the video and the extracted GPX file here, make sure it’s synchronized and hit upload. Once that’s done, it takes one or two days to process the video and your images are published.

So to sum it up, it takes some extra time on my PC, but since I don’t like mounting my phone every time I want to record while driving I like this variant more.
I can’t promise it’s as easy on other dashcams (the Registrator Viewer for example is only for iTracker dashcams) but it’s definitely possible.
I hope it helps you figure out what’s the easiest method for you personally. If you decide to use a dashcam though, I’d recommend a iTracker one, just because of how easy the GPX extraction is. Because if the dashcam doesn’t just place the GPX route into the folder it can be hard to be extracted on some dashcams. Also, at least on mine, you can disable all HUD elements like speed, date/time etc, like I did.
What I also noticed is that the video processing by Mapillary seems to only take very short intervals for images, so that you only go very little steps by clicking “next image” when viewing the images. See an example by me here. But that doesn’t necessarily has to be a bad thing. Also, the processing makes the image quality worse. If you zoom in on my example I just linked you can see that the quality is pretty bad. The videos have had a better quality on my PC. So keep that in mind in case you want to record something that’s worth having a more detailed/zoomed view of.

It has wifi, so I was hoping a direct upload might be possible, somehow.

I highly doubt that. It just makes transferring files to your PC easier I think.

Does the camera write over old data automatically?

Dashcams do this by default, yes. You can usually turn that off though so if the SD card is full it just stops recording.
My 64GB SD card lasts for 7 hours of recording at 2560x1080 and 30FPS. Same for 1920x1080 at 60FPS. It displays how much time is left so I take out the SD card and copy all videos to the PC once I only have 3-4 hours left. So unless you want to record 7 hours or more until you have access to your PC again, it’s fine. But to be safe I usually take out the SD card after every route, unless it’s a short ride to the supermarket or something.

I hoped this helped OP or any other one looking for a dashcam solution.

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8

Will this work on hd dash cam as well?

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Also looking at dashcams, does anyone have one that records in MP4? How much extra work is required to upload?

Thanks

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I recently bought a cheap Azdome GS63H , a dashcam with 4K MP4 recording and GPS, as I was not fully satisfied with my mobile phone performance (blurry). After I found out how to upload the result I am quite happy with the quality.

I will share you some findings using this very cheap, about 55 euro from China, but powerfull dashcam Azdome GS63H. Before I bought, I did some google to find out it is actually working and found this site http://www.fuschlberger.net/cds/dashcam/ describing a workflow to upload images. Based on that workflow I did some finetuning of my scripts using the ‘old’ mapillary tools since I prefer to upload my images using the webuploader to see if I am satisfied with the gps locations. I did also adapt some of the old scripts to remove issues with subseconds so I decided to stick with 1 image per 1 second video in step 2.

My workflow

  • step 1. get gpx traces from MP4 video’s (using nvtk_mp42gpx.py)
  • step 2. get geotagged images from video and gpx (using geotag_video.py)
  • step 3. remove duplicates at traffic lights (remove_duplicates.py)
  • step 4. add directions (interpolate_direction.py)
  • step 5. crop images to remove dashboard view and get good resolution (imagemagick crop)
  • step 6. rename and move all image files with unique name, and create sequences (sequence_split.py)
  • step 7. manually inspect images in sequence folders, delete manually and upload using web uploader, check gps locations

This dashcam can record video in 1920x1080 resolution or FHD, which I cropped to 1600 × 900 to remove parts of my dashboard. Images are in correct resolution after step 2. Its good enough for summer days, but I prefer to have a better resolution which is available:

This dashcam can also record video in 2880x2160 resolution or 4K. BUT there is a special thing you need to know: video players will play this resolution with a hidden tag using 16:9 format (stretch horizontally), so when you get your geotagged images from step 2 you end up in images with a wrong aspect ratio since 2880x2160 is 4:3 , you need correct for this to resize the image to 16:9 , I used following using image magick

convert filename.jpg -resize 2880x1620\! -shave 160x90 filename.jpg

this result in a corrected (down scaled and cropped) picture 2560 × 1440 in 16:9 aspect ratio which is correctly shown in Mapillary.

Example Mapillary

Just writing this so I can remember my own steps later and maybe it helps someone.

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