1

The folliwng should basically have an image appear on frame 438, and then the same image move to a different position on frame 339, then basically disappear for the rest of the video.

ffmpeg -i C:\src\assets\video\base.mp4 -r 25 -i C:\card.png -y \
    -filter_complex [1:v]setpts=PTS-STARTPTS+(1/TB)[1v]; \
    [0:v][1v]overlay=x=0:y=0:enable='between(t,438/25,439/25)'[1v]; \
    [0:v][1v]overlay=x=300:y=300:enable='between(t,439/25,440/25)'[2v]; \
    [1v][2v]concat=n=2:v=1:a=0[out] -map [out] -map 0:a -ss 17 C:\temp\j7kthb0v\composit.mp4

I can't seem to get the actual command correct or output anything that resembles what I need.

I know I'm close, I can get one frame overlayed, but I can't get more than that.

2

Use

ffmpeg -i C:\src\assets\video\base.mp4 -i C:\card.png -y \
       -filter_complex "[0:v][1:v]overlay=x='if(eq(n,439),300,0)':y='if(eq(n,439),300,0)':enable='eq(n,438)+eq(n,439)'[out]" \
       -map [out] -map 0:a -ss 17 C:\temp\j7kthb0v\composit.mp4

You may need to escape the commas in filters depending on your shell i.e. n,438 -> n\,438

18
  • That's awesome, thankyou, much simpler than multiple overlays – Shannon Hochkins Jun 26 '18 at 5:45
  • I didn't ask this in the original post, but I'm using this solution for animation, I want to basically specify a position for X & Y, based on a frame number. I can achieve this doing nested if else hell. but is there a nicer way? – Shannon Hochkins Jun 26 '18 at 6:55
  • Not really. The filter isn't meant for animation like that. You can simplify it somewhat like this: x='0*eq(n,438)+300*eq(n,439)+X*eq(n,567)+...' – Gyan Jun 26 '18 at 7:25
  • I've been playing around with the variable n, in overlay if I were to do: overlay=x='( 605 + -0.8023952095808383 * n)':y='( 406 + -0.4365269461077843 * n)':enable='between(t,438/25,605/25)', does this mean the n would equal 0 and incremented for every frame it's visible for ? (605 - 438) – Shannon Hochkins Jun 26 '18 at 7:41
  • Those expressions mean the overlay starts at (605,406). With each frame, (0.80,0.43) is subtracted and then rounded. But it's only visible (at the computed positions) between times 17.56 and 24.20 – Gyan Jun 26 '18 at 7:46

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