Test patterns:

  ffmpeg -f lavfi -i testsrc=d=60:s=1920x1080:r=24,format=yuv420p -f lavfi -i sine=f=440:b=4 -b:v 1M -b:a 192k -shortest output-testsrc.mp4

  ffmpeg -f lavfi -i testsrc2=d=60:s=1920x1080:r=24,format=yuv420p -f lavfi -i sine=f=440:b=4 -b:v 1M -b:a 192k -shortest output-testsrc.mp4

  ffmpeg -f lavfi -i smptebars=d=60:s=1920x1080:r=24,format=yuv420p -f lavfi -i sine=f=440:b=4 -b:v 1M -b:a 192k -shortest output-smptebars.mp4