Render Only Image (Zoom 1/4)

ffmpeg -i bground.mp4 -i input.mp4 -filter_complex "nullsrc=size=1280x720 [vmain]; [0:v] setpts=PTS-STARTPTS, scale=1280:720 [vback]; [1:v] setpts=PTS-STARTPTS, scale=320:180 [video]; [vmain][vback] overlay=shortest=1 [vid]; [vid][video] overlay=shortest=0:x=480:y=270" -vcodec libx264 -profile:v high -level 4.0 -coder 1 -refs 3 -preset ultrafast -b:v 2932k -minrate 2932k -maxrate 2932k -bufsize 0k -an outinput.mp4 ffmpeg -i outinput.mp4 -vf "zoompan=z='min(max(zoom,pzoom)+0.0015,4)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'" -vcodec libx264 -pix_fmt yuv420p -r 30 -g 60 -b:v 2932k -c:a copy -metadata title="" -metadata artist="" -metadata album_artist="" -metadata album="" -metadata date="" -metadata track="" -metadata genre="" -metadata publisher="" -metadata encoded_by="" -metadata copyright="" -metadata composer="" -metadata performer="" -metadata TIT1="" -metadata TIT3="" -metadata disc="" -metadata TKEY="" -metadata TBPM="" -metadata language="eng" -metadata encoder="" -preset superfast output.mp4