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Extracting GPS Information from EACHPAI dash cam?

Started by Nader, June 21, 2020, 12:48:02 PM

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Nader

Hello Phil,

I am trying to extract GPS data from an MP4 video taken with a dash cam (EACHPAI).

I tried:
exiftool -p gpx.fmt -ee -ext mp4 -w OUTDIR/%f.gpx DIR
but the output file (.gpx) seems empty (attached).

I am certain that the video file has GPS data with time stamps along with other information, because:

1- The video player from the manufacturer can display these information.
2- I used "strings" command in the terminal to pull printable characters from the video file, and i found a lot of massages like this:

"freeGPS
4W`b]S<AGEEBB>@@@<Q<DBD@>HFCE<^<@HCAB>FBGH<g<@>@B<C>CA<@B@FB@<<<Q:GF
free"

I am new to these stuff, but it seems like the GPS data i am looking for are encrypted in those massages. Am i right ?
Someone here posted a similar problem but with a different camera, so i thought i might find help here!

I have the video and the output of the strings command here:
https://drive.google.com/drive/folders/1prhEgwaPVneBP4mXUcRb7FSt-az2-hrv?usp=sharing

Many thanks,

Phil Harvey

Thanks.  Wow, people are coming out of the woodwork recently with different formats of GPS in video files.  I'll take a look at this EACHPAI video too when I get a chance.  Can you tell me the information displayed by the manufacturer software at the start of this video?

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux/PowerShell, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

Nader

Thank you very much. I really appreciate your time and effort!!

Unfortunately, the player doesn't show much. The GPS data are displayed as a drop pin on a map.
I have attached a screenshot to show you how the player look like.
The installation file for the player itself is also available here:

https://drive.google.com/drive/folders/1prhEgwaPVneBP4mXUcRb7FSt-az2-hrv?usp=sharing

Thank you again!


Phil Harvey

Quote from: Nader on June 21, 2020, 12:48:02 PM
Hello Phil,

I am trying to extract GPS data from an MP4 video taken with a dash cam (EACHPAI).

I tried:
exiftool -p gpx.fmt -ee -ext mp4 -w OUTDIR/%f.gpx DIR
but the output file (.gpx) seems empty (attached).

I am certain that the video file has GPS data with time stamps along with other information, because:

1- The video player from the manufacturer can display these information.
2- I used "strings" command in the terminal to pull printable characters from the video file, and i found a lot of massages like this:

"freeGPS
4W`b]S<AGEEBB>@@@<Q<DBD@>HFCE<^<@HCAB>FBGH<g<@>@B<C>CA<@B@FB@<<<Q:GF
free"

I am new to these stuff, but it seems like the GPS data i am looking for are encrypted in those massages. Am i right ?
Someone here posted a similar problem but with a different camera, so i thought i might find help here!

I have the video and the output of the strings command here:
https://drive.google.com/drive/folders/1prhEgwaPVneBP4mXUcRb7FSt-az2-hrv?usp=sharing

Many thanks,

Sorry for the delay in responding.

It looks like this is encrypted ASCII.  The time may be extracted by xor-ing bytes 7-12 (starting from 0) with 0x70 (giving "175522" as the timestamp of the first record in the video).

To decode the rest I will either need more samples (shot in a different location in a different month (and year if possible)), or access to the manufacturer's software (do they have a Mac version?).

- Phil

...where DIR is the name of a directory/folder containing the images.  On Mac/Linux/PowerShell, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).