[FFmpeg-user] Extracting frames from 59.94 FPS video - only every other frame is different

[Moritz Barsnick]

On Mon, Dec 04, 2017 at 09:46:29 +0000, Will Price wrote:

> It's a real shame that the GoPro does this without warning as it will
> make our lives more challenging. We need to compute the optical flow
> of the videos and without an easy method of determining whether
> frames are 'duplicated' or not we'll have to downsample the videos to
> 30FPS.

Perhaps the optical flow algorithm needs to be improved to cover this.
;-)

No honestly: I personally haven't had the greatest success with the
"decimate" filter, but from its description, it can achieve what you
require: Dropping "nearly identical" frames.

https://ffmpeg.org/ffmpeg-filters.html#decimate-1

The optical flow algorithm then of course needs to understand the
timestamps of the video, as subsequent frames will have varying time
gaps.

Moritz