Video from using -use-gpx-only get a non-see through/black background

[troflog]

I am trying to make a video file with gpx only but the backround looks black. Using Shotcut to overlay it but I cannot see anything behind my data.mov file. It looks like some metrics on top of a black background when looking at the file in quicktime.Should it not show some squares?
So that I just could put this data.mov file on top of my mp4 file and only see the gauges from the data.mov file.

It is probably an user error but I can not figure out what is wrong. Now I have to put some opacity on the data.mov so that I can see my gopro video.

python .venv/bin/gopro-dashboard.py --use-gpx-only --gpx tester.gpx --overlay-size 2704x1520 data.mov
Output when running it this:

Using Python version 3.12.9 (main, Mar 17 2025, 21:36:21) [Clang 20.1.0 ]
GPX/FIT file:     2025-09-28T08:55:40+00:00 -> 2025-09-28T08:59:00+00:00
Generating overlay at Dimension(x=2704, y=1520)
Timeseries has 2001 data points
Processing....
FFMPEG Output is in /var/folders/8c/dgj5cyds4ys0qs5qtbq37rt40000gn/T/tmpt751wfve.txt
Timelapse Factor = 1.000
Layout -> Include component 'date_and_time' = True
Layout -> Include component 'date_date' = True
Layout -> Include component 'date_time' = True
Layout -> Include component 'gps_info' = True
Layout -> Include component 'gps-lock' = True
Layout -> Include component 'big_mph' = True
Layout -> Include component 'gradient' = True
Layout -> Include component 'altitude' = True
Layout -> Include component 'gradient_chart' = True
Layout -> Include component 'temperature' = True
Layout -> Include component 'cadence' = True
Layout -> Include component 'heartbeat' = True
Layout -> Include component 'moving_map' = True
Layout -> Include component 'journey_map' = True
Executing ['ffmpeg', '-hide_banner', '-y', '-hide_banner', '-loglevel', 'info', '-f', 'rawvideo', '-framerate', '10.0', '-s', '2704x1520', '-pix_fmt', 'rgba', '-i', '-', '-r', '30', '-vcodec', 'libx264', '-preset', 'veryfast', '-metadata', 'creation_time=2025-09-28T08:55:40+00:00', 'per4.mov']
Render: 1,979 [ 98%]  [ 92.1/s] |###########################################################################################################################################################################################################################   | ETA:   0:00:00Waiting for ffmpeg to complete...
FFMPEG Exited with status code: 0
Finished drawing frames. waiting for ffmpeg to catch up
Render: 2,001 [100%]  [ 91.9/s] |##############################################################################################################################################################################################################################| Time:  0:00:21
Timer(drawing frames - Called: 2,001, Total: 21.65802, Avg: 0.01082, Rate: 92.39)

Using:

{
  "overlay": {
    "input": [],
    "output": ["-vcodec", "png"]
  }
}

[troflog]

Stupid user again. Read the manual about FFMPEG Profiles and there it states that for using --use-gpx-only I have to do the following:

You'll need to create a profile - see FFMPEG Profiles

> {
>   "overlay": {
>     "input": [],
>     "output": ["-vcodec", "png"]
>   }
> }

Then run like this:
python .venv/bin/gopro-dashboard.py --use-gpx-only --gpx tester.gpx --profile overlay --overlay-size 2704x1520 test.mov