Wont recognize gps data of dashcam

Started by dashcam, October 08, 2022, 04:46:33 PM

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dashcam

Hi I have been having trouble with decoding the GPS and MPH data that my dash cam is giving

here is a link to the video https://drive.google.com/file/d/1o2aQxzhlzTt7NmHPzSE76e6J3rghWFXe/view?usp=sharing

   C:\Users\Muhammed Shah>"C:\Users\Muhammed Shah\Desktop\exiftool.exe" -ee "I:\front_norm\2022_09_19_124225_00.MP4"

 ExifTool Version Number         : 12.47
File Name                       : 2022_09_19_124225_00.MP4
Directory                       : I:/front_norm
File Size                       : 210 MB
File Modification Date/Time     : 2022:09:19 12:45:24-07:00
File Access Date/Time           : 2022:10:08 00:00:00-07:00
File Creation Date/Time         : 2022:09:19 12:45:24-07:00
File Permissions                : -rw-rw-rw-
File Type                       : MP4
File Type Extension             : mp4
MIME Type                       : video/mp4
Major Brand                     : MP4 v2 [ISO 14496-14]
Minor Version                   : 0.0.0
Compatible Brands               : mp42, isom
Media Data Size                 : 208099438
Media Data Offset               : 40
Movie Header Version            : 0
Create Date                     : 2022:09:19 12:42:25
Modify Date                     : 2022:09:19 12:42:25
Time Scale                      : 120000
Duration                        : 0:03:00
Preferred Rate                  : 1
Preferred Volume                : 100.00%
Matrix Structure                : 1 0 0 0 1 0 0 0 1
Preview Time                    : 0 s
Preview Duration                : 0 s
Poster Time                     : 0 s
Selection Time                  : 0 s
Selection Duration              : 0 s
Current Time                    : 0 s
Next Track ID                   : 3
Track Header Version            : 0
Track Create Date               : 2022:09:19 12:42:25
Track Modify Date               : 2022:09:19 12:42:25
Track ID                        : 1
Track Duration                  : 0:03:00
Track Layer                     : 0
Track Volume                    : 100.00%
Matrix Structure                : 1 0 0 0 1 0 0 0 1
Image Width                     : 2560
Image Height                    : 1440
Media Header Version            : 0
Media Create Date               : 2022:09:19 12:42:25
Media Modify Date               : 2022:09:19 12:42:25
Media Time Scale                : 120000
Media Duration                  : 0:03:00
Handler Class                   : Media Handler
Handler Type                    : Video Track
Handler Description             : Hisilicon VIDEO
Graphics Mode                   : srcCopy
Op Color                        : 0 0 0
Compressor ID                   : avc1
Source Image Width              : 2560
Source Image Height             : 1440
X Resolution                    : 72
Y Resolution                    : 72
Compressor Name                 : .
Bit Depth                       : 24
Video Frame Rate                : 25.161
Track Header Version            : 0
Track Create Date               : 2022:09:19 12:42:25
Track Modify Date               : 2022:09:19 12:42:25
Track ID                        : 2
Track Duration                  : 0:03:00
Track Layer                     : 0
Track Volume                    : 100.00%
Matrix Structure                : 1 0 0 0 1 0 0 0 1
Media Header Version            : 0
Media Create Date               : 2022:09:19 12:42:25
Media Modify Date               : 2022:09:19 12:42:25
Media Time Scale                : 48000
Media Duration                  : 0:03:00
Handler Class                   : Media Handler
Handler Type                    : Audio Track
Handler Description             : Hisilicon AUDIO
Balance                         : 0
Audio Format                    : mp4a
Audio Channels                  : 1
Audio Bits Per Sample           : 16
Audio Sample Rate               : 48000
Thumbnail Image                 : (Binary data 28108 bytes, use -b option to extract)
Image Size                      : 2560x1440
Megapixels                      : 3.7
Avg Bitrate                     : 9.26 Mbps
Rotation                        : 0 


Then I tried

 C:\Users\Muhammed Shah>"C:\Users\Muhammed Shah\Desktop\exiftool.exe" -ee -V3  "I:\front_norm\2022_09_19_124225_00.MP4"



  Skip = LIGOGPSINFO..####e.    ...."..../........".....n..!....!.....v.."....(....(L..[snip]
  - Tag 'skip' (23656 bytes):
   c800008: 4c 49 47 4f 47 50 53 49 4e 46 4f 00 00 00 00 05 [LIGOGPSINFO.....]
   c800018: b4 00 00 00 23 23 23 23 65 00 00 00 c0 20 20 20 [....####e....   ]
   c800028: 20 f0 12 10 12 22 e9 0e 10 11 2f 99 10 11 01 f6 [ ...."..../.....]
   c800038: 12 18 10 22 b2 1a 10 07 f2 6e 18 13 21 f6 0e 10 [...".....n..!...]
   c800048: 13 21 b1 12 11 02 f3 76 18 11 22 f6 14 0c 13 28 [.!.....v.."....(]
      [snip 23576 bytes] 

I can see the data from app that came with the dashcam called GXplayer

I searched the forums and the only thing I found was

Quote from: cs98jrb on February 03, 2022, 06:12:28 PMHi Phil

I too have a iiway s1 dual dash cam. In the Google Drive folder are the front and rear videos .mp4 and the output of exiftool.exe -ee -V3 FILE
exiftool appears to recognise some GPS info as the output contains:
  + [GPS directory, 16384 bytes]
  |   dd1490: 00 00 40 00 66 72 65 65 47 50 53 20 f0 03 00 00 [..@.freeGPS ....]
  |   dd14a0: 4c 49 47 4f 47 50 53 49 4e 46 4f 00 00 00 00 05 [LIGOGPSINFO.....]
  |   dd14b0: 0a 00 00 00 23 23 23 23 6b 00 00 00 c0 30 20 20 [....####k....0  ]
  |   dd14c0: 20 f0 12 10 12 22 e1 0e 10 12 2f 90 10 13 02 f2 [ ...."..../.....]
  |   dd14d0: 12 18 12 20 bc 1a 11 00 f6 6e 18 11 22 f0 0e 11 [... .....n.."...]
  |     [snip 17176 bytes]
  + [GPS directory, 16384 bytes]
  |   ea1220: 00 00 40 00 66 72 65 65 47 50 53 20 f0 03 00 00 [..@.freeGPS ....]
  |   ea1230: 4c 49 47 4f 47 50 53 49 4e 46 4f 00 00 00 00 05 [LIGOGPSINFO.....]
  |   ea1240: 0a 00 00 00 23 23 23 23 69 00 00 00 c1 30 20 20 [....####i....0  ]
  |   ea1250: 20 f0 12 10 12 22 e1 0e 10 12 2f 90 10 13 02 f2 [ ...."..../.....]
  |   ea1260: 12 18 12 20 bc 1a 11 01 f6 6e 18 11 22 f0 0e 11 [... .....n.."...]
  |     [snip 17800 bytes]

For reference this video was stationary and the location is approximately 52.711, -3.258

Also the GPSPlayer for windows asks for a registration of 9.99 USD to view the GPS data.

Not sure how to covert this data or use the app that was provided in the above forum post.Any help would be amazing !!! thank you in advance



Phil Harvey

I think this may be one of those cameras with encrypted GPS coorinates that ExifTool can't handle, but if you send me a video I'll take a look (philharvey66 at gmail.com)

- 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 ($).

StarGeek

There's a link to a video at the top of the post.
"It didn't work" isn't helpful. What was the exact command used and the output.
Read FAQ #3 and use that cmd
Please use the Code button for exiftool output

Please include your OS/Exiftool version/filetype

Phil Harvey

Quote from: StarGeek on October 08, 2022, 06:35:21 PMThere's a link to a video at the top of the post.

Thanks.  As you must have figured out, I don't read all of these long posts. :P

- 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 ($).

Phil Harvey

I've take a close look at this file.  I've also looked at all of my other "LIGOGPSINFO"-type samples.  Currently ExifTool can't decode GPS from any of them.

Specifically, with your sample, I can see that the individual records are either 100 or 101 bytes long (a size word appears after each "####" character sequence in the trailing "skip" atom of this video, and this is the record size not including a 31-byte header/trailer).  Looking closely at the records, there are a number of bytes that jitter around sort of like accelerometer data, but I can't see anything that looks like a binary value that goes from 73 mph at the start of the video down to 55 mph at the end.  Also, there is definitely nothing that looks like a monotonically changing latitude or longitude as you see in the GPS display of this video.

And other than this LIGOGPSINFO "skip" atom (starting at offset 0xc800008 in the file), I can't see anywhere else the GPS could be hiding.  So this one has me stumped too.  I seriously doubt whether the GPS exists as metadata in the file, but I would love it if someone proved me wrong.

- 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 ($).

dashcam

#5
Yeah it's probably just baked into the video, thanks for taking a look at the video

I'll just have to run a bot to scrape the info from the video

the main reason I'm looking for GPS and Speed data is that I'm doing testing for a project

what's weird is that the GPS player that the dashcam cam with is able to decipher the mp4 file

Below I've liked the gpsplayer.exe and an image of what it looks like.

https://drive.google.com/drive/folders/1_myxBIyPOd4zqEL6Z1itcSoBj3TQP8hf?usp=sharing

Phil Harvey

Very interesting.  The binary data in your file looks very different from that of some of the other files I analyzed.  Data in the other files looked very random, sort of like compressed data, but yours was very regular and I could clearly see the structure, but there were very few bytes that changed between entries, and they didn't change in a regular way, so I can't imagine how the GPS coordinates could have been there.  Perhaps I'm looking in the wrong place.

- 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 ($).

Phil Harvey

Finally I have found the time to work on this puzzle, and solved it!

ExifTool 13.07 will be able to decode this GPS.

- 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 ($).