How to draw - scalable - "EBU safe areas" in ffplay

Question

we need to preview videos with overlayed so-called "safe areas" according to this EBU document: SAFE AREAS FOR 16:9 TELEVISION PRODUCTION.

Here's the scheme for 1080p resolution:

Those consist of three different "zones", each with the same percentage size-to-the-edge of the video frame for any resolution:

• Action Safe Area (GREEN box): 3.5%
• Graphics Safe Area (RED box): 5%
• 4:3 Safe Area (GREY box): 16.25%

It should be easily achieveable using the drawbox command, but how can be dynamically adapted to any video resolution?

Answer 1

Here we go, (driven) ChatGPT did it:

ffplay -vf "drawgrid=x=(iw/2):(ih/2):t=3:[email protected], drawbox=x=(iw-iw*0.95)/2:y=(ih-ih*0.95)/2:w=iw*0.95:h=ih*0.95:color=red@1, drawbox=x=(iw-iw*0.965)/2:y=(ih-ih*0.965)/2:w=iw*0.965:h=ih*0.965:color=green@1" filename.ext