[Libav-user] DLSR-esq 30-second-exposure filter (Light painting filter)
ajn+ffmpeg at junkwall.net
Fri Oct 3 03:19:44 CEST 2014
[Begin scene: in darkness]
Bright point lights moves through the frame, following complex paths.
My DSLR camera takes a 30-second exposure of the scene, accumulating the
light over the entire 30 seconds into a single frame image.
My video camera captures the scene, as a 900-ish frame movie.
I'd like to convert my 30 second video, into a representation of the
what the DSLR image sensor experiences. As in:
- Frame 1 is just frame 1.
- Frame 2 becomes frame 1 + frame 2.
- Frame 3 becomes frame 1 + frame 2 + frame 3
- Frame 900 becomes all frames added together.
I think FFmpeg's filter can do this ...
"overlay input frame N onto output frame N-1."
.... but I can't get my head around the required syntax.
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