Enhancement Suggestion: add timespan(s) option

[keeyor]

This is a great tool, but unfortunately we cannot incorporate it in our project. The video process duration is prohibitive ( FHD video, typically 1 hour long).
Suggestion: since in our videos, faces appear rarely and for a few seconds, it would be great if an option existed where we could mark the time span that the faces appear, so the tool would process just a few seconds and not the entire video. This would significantly speed up the process.

Thanks for your time.

[mdraw]

I don't plan to implement this option but contributions are welcome if you want to work on this. I guess this should be easy to implement in principle by checking the frame timestamp inside this loop for your project but the main difficulty will be to properly expose this functionality in the CLI, document and maintain it.

Alternatively I suggest trying out the --scale option to run the detector on a downsampled frames. The output video size stays the same but processing can be greatly sped up at the cost of accuracy. See https://github.com/ORB-HD/deface/blob/master/README.md#high-resolution-media-and-performance-issues.