feature request: allow dashboard overlay stream to stdout?

[williamjoy]

First of all thanks for your work, appreciated!

It seems impossible/difficult to use gpu acceleration inside docker on macos/apple silicon, would it be possible to allow generate stream and pipe to ffmpeg on host machine?

Similar to this https://github.com/time4tea/gopro-dashboard-overlay/tree/main/docs/bin#creating-videos-using-only-gpx-file

venv/bin/gopro-dashboard.py --use-gpx-only --gpx ~/Downloads/Morning_Ride.gpx --profile overlay --overlay-size 1920x1080 GH020073-dashboard.mov

probably to generate raw stream (without ffmpeg processing) to stdout venv/bin/gopro-dashboard.py --use-gpx-only --gpx ~/Downloads/Morning_Ride.gpx --overlay-size 1920x1080 --stream-only [FILE_NAME | -] ?

• To stream it outside container:

venv/bin/gopro-dashboard.py --use-gpx-only --gpx ~/Downloads/Morning_Ride.gpx --overlay-size 1920x1080 --stream-only - | socat STDIO TCP4:docker-host:4321

• On host machine, run socat server and pipe to ffmpeg with -hwaccel

socat TCP-LISTEN:4321,reuseaddr,fork EXEC:"ffmpeg -hwaccel videotoolbox -hide_banner -y -hide_banner -loglevel info -f rawvideo -framerate 10.0 -s 3840x2160 -pix_fmt rgba -i - -r 30 -vcodec png xxx.mp4"

[time4tea]

Thanks for your interest in the software!

There are a couple of considerations which make things a bit more complicated:

• ffmpeg determines the output format from the filename, so we'd need to add more controls there to tell it what format
• mpeg itself cannot be written to a stream, as it needs to write some information at the start of the file when it finishes, so we'd need to use a different file format - maybe an mpeg transport stream.

if that stuff was working...

• in theory we could just stream the stdout of ffmpeg through docker, but i'm not sure how performant that would be, especially on mac, as docker works a bit differently on mac, and docker logging infra might be upset with us anyway.

i'm not too keen on reaching outside the container, as this can get messy. docker is mostly provided as a convenience tbh, and all this sounds like it could get complicated.

my thoughts ->

• generate a raw video file, this will be enormous, but then you can compress it after, and disks are pretty big
• don't use docker and just install the software on the mac directly, you'll definitely get much better performance.

[time4tea]

On further thought... I think this capability is already supported...

1 ) set up a profile that will create a stream (see the docs on profiles)

    "png-stream": {
        "input": [],
        "output": ["-vcodec", "png", "-f", "matroska"]
    },

2. use an output "filename" that points to network socket: "tcp://127.0.0.1:1234?buffer_size=10M"

This gives a command line like this:

gopro-dashboard.py --profile png-stream render/GX020357.MP4 'tcp://127.0.0.1:1234?buffer_size=10M'

Then you need to connect something at the other end that will listen to it and process.