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WebApp Guides

Speaker Selection — Studio

Speaker selection lets you pick which person gets lipsynced in a video or image with multiple people. You can manually click a face, or for videos, use Active Speaker Detection to let Sync Labs identify the speaker automatically. If a detection lands on the wrong person, drag or resize its box onto the correct face. If no face is detected, you can place a box yourself. For programmatic usage via the API, see the API guide.

Speaker selection is available with our lipsync-2, lipsync-2-pro, and sync-3 models in both Lite and Advanced modes. Note that react-1 does not currently support this feature. For sync-3 image inputs, only manual face selection is supported — Active Speaker Detection is video-only.

Selecting a Speaker in Video

1

Upload your video

Upload a video that contains multiple people. Sync Labs detects the number of speakers in the background.

Studio overview

2

Enable face detection

Click the icon in the video player controls. Green bounding boxes appear around detected faces with a hint: “select which speaker to lipsync.” If no boxes appear, see When No Face Is Detected below.

Face detection active

3

Click on the speaker's face

Click on the bounding box of the person you want to lipsync. The selected face gets a bright green border and a face thumbnail appears in the controls.

Face selected

4

Generate

Click the Sync Labs button. The speaker configuration is sent automatically with your generation request.

Changing or Clearing Your Selection

Once a speaker is selected, Studio shows only the selected box.

  • Click the X on the face thumbnail to show the detected faces and select another speaker.
  • Scrubbing through the video re-runs detection.
  • If the selected or auto-detected box lands on the wrong person, drag the box onto the correct face, or drag a corner to resize it — the face thumbnail updates to match.

When No Face Is Detected

When no face is detected in your video, the hint offers a place a box action. Choosing it places a box on the current frame. Drag or resize it onto the intended face, the same way you’d correct a wrong detection.

If visible faces are not detected, your browser may be unable to decode the video’s frames. This can happen with HEVC video when the browser lacks the codec. Try another supported browser, or convert the video to H.264 and upload it again. See media formats.

Active Speaker Detection

As an alternative to manual selection, toggle Active Speaker Detection in the Studio settings panel. Sync Labs identifies the speaker via lip movement analysis — no manual click needed.

Manual selection and Active Speaker Detection are mutually exclusive — you can only use one at a time. Active Speaker Detection may not work reliably on silent or low-motion clips.

Selecting a Speaker in Images (sync-3)

For images with multiple faces, you can select which person to lipsync using the same face detection overlay.

1

Upload your image

Upload an image with the sync-3 model selected. Face detection runs automatically when the image loads.

2

Click on the speaker's face

If multiple faces are detected, click on the face you want to lipsync. The selected face gets a bright green border and appears in the controls.

3

Generate

Click the Sync Labs button. The speaker coordinates are sent with your generation request.

Active Speaker Detection is not available for image inputs — only manual face selection. If your image contains a single face, the system skips the selection step automatically.

  • Lipsync Model — learn about supported models including lipsync-2 and lipsync-2-pro
  • Quickstart — get started with your first Sync Labs generation