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Hard encoding multiple subtitle telemetry/video files in VLC

Hi all,
The newest software releases seem to have the subtitle/telemetry overlay system working really well, thanks to all involved!

I’ve been playing around with it for a few days, and seem to have a decent workflow for hard-encoding the overlay to an mp4 file. It’s not that intuitive in VLC, but maybe I’m missing something, and happy for other users to add suggestions. If you’re interested, I put together on how the overlay works/looks, and also how to go about hard-encoding.



Nice job! We needed something like this!

I also managed to do it with ffmpeg:
ffmpeg -i input.mkv -vcodec libx264 -crf 18 -vf subtitles=subtitles.ass out.avi
(crf controls the output video quality)

And with a suspiciously looking software called “Format Factory”, which has weird default fonts but did work.

I also couldn’t find what caused the “Dropped frames”, but in my early tests the ffmpeg generated files were better.

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Thanks @williangalvani, will look at those other methods as well. Do you have any references to how/where the .ass file is generated from the telemetry, and the formatting? I would like to try a few different overlay options.


Hi @spotxuv,

This is the file responsible for generating the subtitle files. It uses the values currently displayed in the values widget to the right of the screen and tiles them at the bottom of the video.

There is a better explanation at the QGC docs section on Video Overlay.

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Do you know if the recording feature/video overlay is restricted to the stock camera 1080P? For example, if a 4K camera is connected and integrated to QGC using RTSP, will the recording and .ass files still work as intended? Am hoping to try this out soon, but would be good to know upfront if not possible

Hi @spotxuv,

It should work fine with any video at all.
You could even record video with a gopro and load the subtitle/overlay alongside that (you would probably have to take some time to sync it, though).

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