Dash Cameras – Sergei's incoherrent ramblings

Predatory practices of Dash Cam manufacturers

Recently I was contacted regarding my dash cam GPS coordinate extraction script. The request was regarding wrong data being produced. I have addressed something similar in the past, so I decided to have a go at this one (I like a challenge).

Unfortunately I was presented with this:

00052eb0  00 20 00 00 63 6c 75 72  00 00 40 00 66 72 65 65  |. ..clur..@.free|
00052ec0  47 50 53 20 f0 03 00 00  59 6e 64 41 6b 61 73 6f  |GPS ....YndAkaso|
00052ed0  43 61 72 00 00 00 00 00  00 00 00 00 00 00 00 00  |Car.............|
00052ee0  00 00 00 00 00 00 00 00  16 00 00 00 16 00 00 00  |................|
00052ef0  39 00 00 00 e5 07 00 00  04 00 00 00 08 00 00 00  |9...............|
00052f00  41 4e 57 00 00 00 00 00  ad bb 79 aa 9f 20 c6 40  |ANW.......y.. .@|
00052f10  c9 fd 0e 45 91 98 c1 40  37 a6 75 41 33 33 a7 41  |...E...@7.uA33.A|
00052f20  33 58 5a 55 4e 4e 31 35  39 35 32 39 37 34 36 35  |3XZUNN1595297465|
00052f30  59 4e 44 53 01 00 00 00  00 00 00 00 00 00 00 00  |YNDS............|
00052f40  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

Poking about I realised the data is not simply obfuscated…

Eventually I stumbled upon this:
https://exiftool.org/forum/index.php?topic=11320.0

According to exiftool forum the player uses an internet service to decode the data, which is a huge bummer.

I will try to decompile the player but at this stage I don’t believe I will have any success.

To add an insult to injury the dash cam manufacturer asked the dash cam owner not a small amount of money to decrypt these coordinates. Actually you could outfit a small fleet with new cameras from Viofo for the amount of money they asked.

So here are the brands so far to avoid (do not buy them):

AkasoCar
ANKEWAY

or any brand that requires their own player to playback the coordinates.

nvtk_mp42gpx.py revisited – now with TS support

It appears that not only my quick hack of a script is popular but also that the dashcam manufacturers keep changing things.

In this case the biggest change (beyond utterly stupid data obfuscation) is the switch to the TS format.

In retrospect TS format is an obvious choice for something like dashcam as it is very resilient to crashes (no pun intended).

TS format unlike the MP4/MOV format is very simple, it is pretty much made up of fixed 188 byte segments which have ASCII ‘G’ as a header. The actual payload lives in last 184 bytes while the first 4 bytes are reserved for header (of course this is all simplified).

The biggest difficulty of adding TS functionality is that Blueskysea B4K camera was engineered by sadists and they split the payload into two packets (arbitrary cutting off at the seconds 4 bytes). If you are the person at the BlueSkysea who made this obfuscation – fuck you.

In anyway this update is massive rewrite.
Just to make it easy here is the script: nvtk_mp42gpx.py

2020 update of the nvtk_mp42gpx.py script

Surprisingly to me the script that I haphazardly put together turned out to be very popular.
I decided to quickly update it (after multiple feature and bug fixes requests)…

The highlights are:

Automatic finding of the correct position of the data block (more on that below).
Introduction of -m flag, which creates separete GPX file per input file (default behaviour is a single GPX output file for multiple input files).
More robust argument parsing (now it should always display help if wrong arguments are used)
Introduction of -d flag, which allows to de-obfuscate GPS coordinates.

One year with Mini0806

WARNING: DO NOT BUY MINI0806 UNDER ANY CIRCUMSTANCES.

You have been warned.

Here is simple reason why: out of 8 mini0806s that passed through my hands, 5 failed and one dying(failure rate >60%).
Continue reading One year with Mini0806

Extracting GPS data from Viofo A119 and other Novatek powered cameras

The script.
nvtk_mp42gpx.py
Here it is: nvtk_mp42gpx.py
Alternative version: nvtk_mp42gpx_older.py

What does it do?

This script will attempt to extract GPS data from Novatek MP4 file and output it in GPX format.

Usage: ./nvtk_mp42gpx.py -i&lt;inputfile&gt; -o&lt;outfile&gt; [-f]
        -i input file (will quit if does not exist)
        -o output file (will quit if exists unless overriden)
        -f force (optional, will overwrite output file)

In short: it takes Novatek encoded MP4 file (with embedded GPS data) and extract GPS data in GPX format (as separate file). Note; it does not modify the original MP4 file.

In long:

Viofo A119

Box:

Camera:

GPS mount:

Mounting position:

A119 vs A118c:

A119 vs A118c vs DR400G-HDII vs Mini0806:

To be continued…

mini0806 design flaw

Alternative title: why my mini0806 was crashing and stopped working after a light drop.

One of the differences between mini0805 and mini0806 is this heat sink:

It is a bitch to remove, so I gently coerced it with a blade:

After some time of gentle pushing and heating it managed to peel off:

Revealing Samsung ram chip and Ambarella A7LA50 SoC:

Here is why it was not working after slight drop (and crashing before that):

Pulled out pads! Note that the blade I used to remove would cause other side of pads missing if I applied too much pressure.

My theory is following: the heat sink that bridges RAM and SoC is causing stress on these chips. Mostly because it is glued and not mechanically pressed against the chips. This is a very silly design flaw, if for example, only SoC would have the heat sink (like found on IP cameras) then there would not be any stresses. I don’t think RAM needs heat sinking on those things.

I am tempted to take dremel to my other mini and split the heat sink in two…

inside of Mini0806

Update: if you ever thinking about buying this camera, don’t! Unless you wish to buy five them to get one good. It is plagued with issues, from assembly problems (jammed cable), crappy firmware, stability issues, poor choice of power supply IC (only 0.5V head room), random crashes to shitty plastic case that melts at 100’C.

Below is the breakdown of mini0806 dashcam.

The packaging contents:

Camera itself:

To open pop the rear cap with fingers:

There are screws behind it holding the whole camera together:

Notice torn cable inside of the ring? This is a common assembly/design fault:

The shell is easily separated:

The beefy heat sink is a good thing to have, I believe it is relatively easy to add a micro fan there (maybe with minimal case cutting).

The two boards held together quite tight. Here is the camera side:

Here is the back side:

Notice how battery is simply jammed between two halves? It is held by double sided tape…

Under the battery:

I have added insulation tape around battery area in case the battery swells in future:

Camera is easily assembled back, one thing to watch out for is the power/GPS cable that feeds through the ring. It can be easily jammed and torn by adjusting the angle, if it is not assembled carefully. I bolted the contact pad last which allowed me to check if the cable is jammed.

Navman (Mio) MiVue 388

I bought Navman MiVue 388 for holiday in Australia, as I was going to do a few thousands kilometres worth of driving.
This camera is sold everywhere else under Mio brand. It is not a Navman product.
When I was purchasing this dash camera I had few prerequisites (which it met, somewhat):
1) 1080p
2) suction cup mount (for easy removal from rental)
3) Modest size
4) Available next day
5) Reasonably priced (under $250)
6) GPS
So basically the only product in New Zealand that met those was this camera.

Whatever you do, do not buy this dash camera. There is nothing really positive I can write about it (apart that it supports 64GB VFAT formatted card, despite the specifications). It pales in comparison to a much cheaper G1W, or Mini0806 (also crap! DO NOT BUY THESE!) or even my dated Blackvue DR400G-HD II. If you are after a good value for money camera get G1W for ~$60USD. Same applies to MiVue 338/358.

Image quality is very grainy:

I didn’t test the camera with optional CPL filter as Navman didn’t sell it at the time (it could have been sources from eBay as Mio branded).

Beyond image quality there are other major issues:

* Suction cup mount is a standard GPS mount, is way too big and vibration prone. It is not very good and falls off after few hours. Not possible for discreet mounting in a smaller car without major view obstruction.
* After 1 month of operation the face plate (screen cover) fell off. It was stuck on by two short strips of double sided tape. After reattaching second time, I gave up and now the camera is used without it.
* Occasionally it decided to completely lose time settings and gets stuck on Setup Time screen. While in that state it does not record!!!
* Cannot turn off blue pixelated “MiVue388” logo on top of the screen (without hacking firmware).
* Battery life is hopeless (about 1 minute and 30 seconds). Good luck actually using park mode.

Two of the issues were because of the climate in New Zealand; this camera is not suitable for being attached permanently on the windscreen due to heat. It is probably far worse for it in Australia.

To address the shitty mount I have decided to build my own mount (secured by not suction cup but double sided tape).
The materials I used are the following:

* Piece of scrap aluminium plate (some random cut off)
* A random drawer knob that I found at hardware store (a 16mm ball with threaded hole and a screw).
* 3M moulding tape
* Black paint

Test fit:

Painted and assembled:

Finished product:

With my mount the dash cam no longer blocks the view, in fact it is almost not visible (apart from status LED) from drivers seat. It is also very discreet from outside as it is masked by mirror contour.

Converting Blackvue Dashcam gps log

It appears that Blackvue dashcams log GPS data in “almost” NMEA format.
It is possible to convert the file using gpsbabel utility into KML format that google maps/earth can understand.
All you need to do is strip time stamp appended to each line in the log and them process the output with gpsbabel:

cat {BLACKVUE_GPS_LOG}.gps | awk -F ']' '{ print $2 }' | egrep -v '^$' > {BLACKVUE_GPS_LOG}.nmea
gpsbabel -i NMEA -f  {BLACKVUE_GPS_LOG}.nmea -o KML -F {BLACKVUE_GPS_LOG}.kml

This is what log looks like:

[1389266060242]$GPRMC,221417.990,A,4533.1826,S,16737.5506,E,054.7,035.5,080114,,,A*77

[1389266060242]$GPVTG,035.5,T,,M,054.7,N,101.4,K,A*0C

[1389266060242]$GPGGA,221418.990,4533.1701,S,16737.5631,E,1,11,1.1,204.6,M,1.7,M,,0000*78

[1389266060242]$GPGSA,A,3,16,07,03,19,23,13,10,06,09,27,08,,2.0,1.1,1.7*3D

[1389266060242]$GPGSV,3,1,12,13,80,310,39,07,50,247,36,23,50,019,48,03,48,066,46*71

[1389266060242]$GPGSV,3,2,12,16,45,128,43,27,42,084,44,06,41,096,44,19,28,038,46*79

[1389266060242]$GPGSV,3,3,12,10,26,260,31,08,19,261,32,09,16,257,26,05,06,210,*77

[1389266061239]$GPRMC,221418.990,A,4533.1701,S,16737.5631,E,054.8,035.0,080114,,,A*7F