Guide
What's a flash frame, and how to catch them before the client does
A flash frame is one frame that doesn't belong: a sliver of the wrong clip, or a frame of black, left behind at a cut. At 30 fps it's on screen for a thirtieth of a second, so you can miss it in playback, but viewers feel it as a jump and clients spot it on the second watch.
How they happen
- Trimming a clip and leaving one frame of the old clip behind.
- A one-frame gap between two clips, which exports as a frame of black.
- Swapping a shot for a new version that's one frame shorter.
- Nested sequences or replaced footage that don't line up exactly.
How to find them by hand
- Zoom the timeline in until single frames are visible, and step across each cut with the arrow keys.
- Look for tiny clips and gaps on every video track, not just the top one.
- Watch the export at half speed. It's slow, but it catches what full speed hides.
How to find them in seconds
This checker looks at every frame of the exported file and flags any single frame that's very different from the frames on both sides of it. A normal cut doesn't count, because the frames either side of a cut are different from each other too. You get the timestamp and a thumbnail of the frame.
Check your export in seconds
Drop in the file and get a pass/fail list for size, loudness, safe zones, and black and flash frames. It runs in your browser, so the video is never uploaded.
Check a video free