BlackVue dashcam

Started by dh, March 02, 2022, 02:57:39 AM

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dh

Hi

Edit: I discovered the -q -q option to clean up the output. Sorry for the noise

I'm working with GPS data from several video cameras, and trying to rationalize the methods for data extraction for different models, especially those with embedded data. Now I've discovered that ExifTool can extract data from video, I'm giving it a go.

I'm having trouble using ExifTool with output from the BlackVue models.

Using ExifTool 12.40

exiftool -ee3 -globalTimeShift +8 -p "$gpsDateTime,$gpsLatitude#,$gpsLongitude#,$gpsSpeed" C:\Work\VideoSamples\BlackVueH265.MP4

The intention is to use the .Net command process, but in the Windows cmd.exe the sample file produces masses of minor errors along the lines of 'Doc739:gpsDateTime' not defined, in fact so many that the command window can't show all of the output. It does however produce the correct result amongst the errors

There doesn't seem to be any issues when using tags instead of the -p option

Using  the .Net command process, it was unable to complete with the output redirected, but the cmd window errored with device not ready.
I retried with the -m option and this time the cmd window displayed partial output with comma separated empty strings in place of the errors, and the .Net command process printed all of the same output and I was able to see that the actual data had been repeated once.

I'm not sure how ExifTool deals with this format, but my own method involves reading the bytestream having been unable to identify any suitable metadata streams.

On another related note. Is there any way to determine the GpsSpeed units? These appear to be Km/h where the GoPro appears to be m/s

Any assistance appreciated