An overlay comparison plays one video directly on top of another, so two attempts of the same movement occupy the same space on screen. Where side-by-side asks your eye to jump between two pictures, overlay makes any difference — a lower hip, a wider stance, an earlier release — appear as a visible split between the two bodies.
When overlay beats side-by-side
- Same athlete, same camera, two attempts. The gold case: rep 3 vs. rep 8, filmed from a tripod. Everything matches except the technique difference you're hunting.
- Before and after a cue. Give the instruction, film again, overlay: did the change actually happen, and how big is it?
- Path and trajectory questions. Bar path, club path, jump height — overlay puts both trajectories in one coordinate system.
Side-by-side stays the better tool when the two videos differ a lot (different camera distance, different athlete, different location) — see the side-by-side guide. Overlay rewards consistent filming; from a tripod it's devastatingly clear.
Setting up an overlay
- Load both videos, then tap Layout and pick one of the two overlay modes — video A over B, or B over A. Which video is on top changes what reads best, so try both.
- Align in space. Pinch-zoom, drag, rotate, and horizontally flip each video independently until a fixed landmark — a line on the court, the tee, the squat rack — sits in the same place in both. The Grid overlay helps you check the alignment against straight lines.
- Align in time. Step each video frame by frame to the same event (contact, takeoff), then tap Lock. Both clips now play and frame-step in sync, and the ghost effect appears: two bodies moving through one frame.
- Slow it down. Overlay at 1/4 speed is where the differences tell their story; at full speed they smear together.
Reading an overlay honestly
- Anchor on something fixed. If the camera moved between takes, alignment on the background will be imperfect; align on the most relevant fixed object near the athlete instead.
- One difference at a time. Overlay shows everything at once, which can overwhelm the athlete. Freeze on the key frame, draw one line with Markup, make one point.
- Mind mirror-image athletes. Comparing a lefty with a righty? Horizontally flip one video first — the overlay then compares mechanics rather than handedness.
Exporting the ghost
A linked overlay exports like any other layout: save it as a video or GIF with your drawings included, Clip the key seconds, or freeze the split moment and capture it into a kinogram. Sending the athlete a three-second ghost GIF of their two attempts is often the single most convincing piece of feedback they'll get all season.
Overlay videos in Coach Video Analysis
Two overlay modes in the Layout picker, independent zoom, rotation, and horizontal flip per video, frame-accurate Lock syncing, grid alignment, and slow motion down to 1/16 speed. iPhone, iPad, and Mac — free to download.
