Strobe Effect
Strobe effect for video: flash the frame to black, white, negative or gray at a rate you set, or lock it to a song's beat. Opens at a safe two flashes a second.
Is a strobe effect safe to post?
Fast flashing can trigger seizures in people with photosensitive epilepsy. The web's accessibility guidelines, WCAG, set the line at three flashes in any one second for anything large and bright. This page opens at Rate 2, two flashes a second, to stay under it, and on the Gentle preset, whose flash only darkens the picture to 60 percent.
You can raise Rate up to 20 and Amount up to 1, and a club visual may need both. If you do, add a flashing-lights warning wherever you post the clip. A soft flash, or the Mono mode, which only drains the color, is much less of a risk than a black and white flash at full strength.
The settings
Rate is how many flashes happen a second. Duty is how long each flash lasts, as a share of its cycle: 0.5, the default, is half on, half off, and a small Duty gives short, sharp blinks. Amount is how strong the flash is. Phase shifts the flash within its cycle, which lets two strobes on different layers take turns.
Mode picks what the flash does: Blackout cuts to black, Whiteout to white, Invert to a negative, and Mono to grayscale. The presets are Black strobe, White flash, Negative, Gentle at Amount 0.4, and Offbeat, which moves the flash half a cycle later.
How do you sync a strobe to music?
Add a song, then detect its tempo. Set Sync to Beat, and the flashes lock to the song's beat instead of running on their own clock. Division sets how many flashes fit in each beat, from one every four beats upward. One a beat on a dance track is already about two flashes a second, and that's usually enough.
For a full music video, pair it with the Audio Visualizer, or with Screen Shake Effect on the same beats, so the picture jolts as it flashes.