Neat project, you may want to consider adding audio processing too (eg sound detected) as part of the video.

You could go deeper and compare samples of audio that could be uploaded separately (eg, siren sounds), check out MFCC processing https://en.wikipedia.org/wiki/Mel-frequency_cepstrum#Applica... to do Shazam-style audio comparison.

I wonder too if you process it on a per-frame basis or you can take series of frames too (eg analyze the last 5 seconds of frames) to detect things like a "hand wave".