CODEWITHSUNDEEP
ffmpeg
CrosswordPuzzlz
CrosswordPuzzlz

Reputation: 55

Is there a way to tell ffmpeg mpdecimate to only evaluate a specific part of the frame?

I have a 60 FPS screen recording of a significantly slower, variable frame rate, video. It is supposed to, however, be constant frame rate.

Fortunately, frame numbers are present in a fixed area of the screen. Within that area, the only time anything changes is when the frame number changes.

(There are sometimes changes between frames - in other parts of the frame - that I would like mpdecimate to ignore. Those changes, however, never appear in the frame count zone.)

Is there a way that I can tell mpdecimate to only evaluate that small 'frame counting' portion of the frame in determining whether sequential frames are duplicates?

Thank you.

Upvotes: 1

Views: 1402

Answers (1)

Gyan
Gyan

Reputation: 93251

The basic method here is to clone the input stream, paint over the undesired portion of the frame with a solid color in one of the copies, run mpdecimate filter, then overlay the untouched copy on top of the de-duplicated copy.

Assume the bottom bar is static except for the frame counter and occupies the bottom 5% of height. drawbox will draw a white box over the top 95% of the frame.

ffmpeg -i in -vf "split=2[full][masked];[masked]drawbox=w=iw:h=ih*0.95:x=0:y=0:t=fill:c=white,mpdecimate[deduped];[deduped][full]overlay=shortest=1" -vsync vfr -c:a copy out

Upvotes: 2

Related Questions