video - Create a rolling X second webcam buffer in Linux, press button saves to file -

video - Create a rolling X second webcam buffer in Linux, press button saves to file -

i'm working on webcam installation 'instant replay' feature. concept this:

webcam captures live, 24/7 when user presses key, last (previous) 30 seconds of video saves file i'll compress video using ffmpeg , upload remote server

i'm fine step 3 , beyond, haven't been able find solution equivalent of fifo buffer video streams [i.e. pretty much 'rewind live tv' buffer on tivo does].

does know of way maintain rolling webcam video/audio buffer can exported file?

design considerations:

i'm planning utilize standard webcam, open other suggestions recording ideally 1080p, 30fps recording must include sound linux hardware , os can specified in answer, there no existing pre-requisites. raspberry pi nice if that's possible, as fine little intel machine (e.g. nuc). there's no requirement save 24/7 stream, it's ok if that's by-product. so, storage permitting can saving file continuously 12 hours , 'cat' lastly 30 secs separate file, if that's option? improve 30 sec rolling fifo buffer potentially whole job in ram. the 'save instant replay' button physical pushbutton rather keyboard key. however, i've got side of things covered (if solution rpi i'd utilize gpio pins, if it's intel box i'd utilize arduino in hid mode simulate keyboard press).

linux video ffmpeg webcam