I 'd like to create a 16/9 video from an image that is not exactly 16/9; I can add black lines aside, to fit 16/9, but I'd like to create a background with same image, with a boxblur applied; the result will be the original image, fit at 16/9, with the same image, blurry, visible instead of blank side lines.
I'm trying to do with split filter, something similar to this:
[0:v]split=2[v0i][v1i];\ [v0i]scale=iw*3:ih*3,boxblur=5[v0f];\ [v1i][v0f]overlay=(W-w/2):(H-h)/2[v0];\ [v0]\ scale=iw*min(640/iw\,360/ih):ih*min(640/iw\,360/ih), pad=640:360:(640-iw)/2:(360-ih)/2\ [v00];\
but I think I miss something ... can someone help me? thanks ...