[FFmpeg-user] deep zoom-in

[Michael Koch]

>
> 2. It would be nice to have an expression for a lookup table, for example
>
> lookup(x, y0, y1, y2, ... , z)
>
>    Evaluate x, and if the result is 0 return y0, if the result is 1
>    return y1, and so on, else if the result is out of range return z.
>


I found a workaround for a lookup table. The following example makes a 
slideshow where each picture is shown 1 second (25 frames), except the 
3rd picture is shown 3 seconds (25+50 frames) and the 5th picture is 
shown 5 seconds (25+100 frames).

ffmpeg -start_number 400 -i IMG_%%4d.jpg ^
-vf "zoompan=d=25+'if(eq(in,3),50,0)'+'if(eq(in,5),100,0)'" ^
-c:v mpeg4 -s 1800x1200 -b:v 5M -q:v 2 test.mp4

Maybe it's useful to add this example to the documentation of the 
zoompan filter.

Michael