Slow-motion, frame-by-frame swing analysis in your browser

At full speed, the parts of the swing that decide where the ball goes are over almost before you see them.

Transition, the change of direction at the top, lasts only a few frames. Impact is a single frame. Watch your swing in real time and you see the general shape, but not whether the club moved outward at the start of the downswing or whether your hips moved toward the ball at impact.

Slowing the video down helps you see the movement. Stepping frame by frame lets you stop on the exact moment. You need both:

• Slow playback to find roughly where something happens.
• Frame stepping to land on the one frame that shows it.

Once a video is loaded, the controls sit under the clip.

• Speed: 0.25x, 0.5x or 1x. 0.25x is quarter speed, best for transition and impact. 0.5x works for watching the whole swing and finding roughly where each checkpoint is.
• Play and pause. On a phone, you can also tap the clip itself to play or pause when the select tool is active.
• Frame step. The previous-frame and next-frame buttons move the video by about one frame (1/30 of a second). Tap repeatedly to walk through a move.
• Scrubber. Drag along the timeline to jump to any point in the clip.

On a laptop or desktop there is more:

• Zoom with Cmd or Ctrl and the scroll wheel, or the zoom buttons on the canvas. Zoom in on the hands or the clubhead at impact.
• Pan by holding Space and dragging.
• ±1 second buttons for bigger jumps.

On a phone, the clip is fitted to the screen and there is no zoom. If you need detail on the hands or the club, crop your video closer before uploading or do that check on a laptop.

Drawing turns "that looks a bit off" into something you can measure. There are three drawing tools, each suited to a different job.

Line

Use it for anything that should stay straight or stay put. Draw one up your spine at address and leave it there for the rest of the swing to see whether your posture holds. Draw one along the shaft at address, then compare the downswing shaft against it. A vertical line at your backside at address is the quickest check for early extension.

Circle

Use it to mark a position you want to track. Circle your head at address and step through the swing to see how far it moves. Circle the hands at the top to see where they sit compared with your shoulders.

Angle

Use it to put a number on a joint. Tap the corner (the vertex) first, then one end, then the other, and the tool shows the angle in degrees. The lead elbow at the top of the backswing is a good one: tap the elbow, then the shoulder, then the wrist.

Drawings stay on the clip while it plays, so a line drawn at address becomes a reference for every frame after it. Undo and redo are there if a line goes wrong.

You don't need to study every frame. Four of them answer most questions.

• Address. Posture, ball position and alignment. Draw your spine line here. The step-by-step guide explains what to look for.
• Top of the backswing. Shoulder turn, lead-arm structure and where the club points. Measure the lead elbow with the angle tool. Comparing this frame with a pro's is covered in compare your swing to a pro.
• Transition. The first few frames of the downswing, from the top until the hands reach about hip height. This is where over the top and casting show up. Use 0.25x and single frames.
• Impact. One frame. Check whether the hands lead the ball and whether your hips have moved toward it compared with address, which is the sign of early extension.

Find address and the top at 0.5x. Switch to 0.25x and frame stepping for transition and impact.

There are two different things people mean by slow motion, and they give you different amounts of detail.

Slowing down normal video (playing a regular clip at 0.25x) stretches the frames the camera recorded. It doesn't add any new ones. If the camera missed the exact moment of impact, slowing it down won't find it.

Filming in slow-motion mode on your phone records many more frames per second. Each frame-step then covers a much smaller slice of the swing, so you are far more likely to have a frame right at impact or at the change of direction.

In practice:

• Use your phone's slow-motion mode when you film if it has one. It makes transition and impact much easier to read.
• Regular video is still fine for address, the top and the finish, where the body is moving slowly.
• Keep the phone still and level, on a tripod or propped on your bag. Slow motion makes camera shake look worse.

The filming guide covers camera height, distance and the two angles worth filming.

When you have found the frame you care about, you can ask for feedback on it.

1. Pause on the frame. Address, the top and impact give the clearest reads.
2. Tap AI on mobile or AI Coach on desktop, then Analyze Current Frame.
3. You get the swing phase it sees, up to three strengths, up to two fixes and one drill.

Only the paused frame is sent for analysis. Your video stays on your device.

Because it reads a single still frame, the AI can't judge tempo or the motion between frames. That is what your slow-motion playback is for. Use the two together: step through to find the position, draw your lines, then ask the AI about that exact frame.