A flash or rapidly changing image sequence is below the threshold (i.e., content passes) if any of the following are true:
there are no more than three general flashes and / or no more than three red flashes within any one-second period; or the combined area of flashes occurring concurrently occupies no more than a total of .006 steradians within any 10 degree visual field on the screen (25% of any 10 degree visual field on the screen) at typical viewing distance
where:
A general flash is defined as a pair of opposing changes in relative luminance of 10% or more of the maximum relative luminance where the relative luminance of the darker image is below 0.80; and where "a pair of opposing changes" is an increase followed by a decrease, or a decrease followed by an increase, and
A red flash is defined as any pair of opposing transitions involving a saturated red.