Video import and camera tracking
Replica can reconstruct a scene from a MOV or MP4 video and solve the camera's path through it. You can check the result in the viewer and export it for compositing. These features are available in Free, Lite and Pro.
Record the video
Move around a stationary subject and keep plenty of overlap between views. Capture sharp images with recognisable surface detail. Keep the lighting steady and leave the lens, zoom and focus unchanged: the VFX export uses one lens calibration for the whole video.
For a model at a known scale, include a measured object or an AprilTag bar in the shot. Keep the reference still during calibration. See AprilTag Scale Bar for capture instructions.
Import the video
- Click + → Import Video… and choose a MOV or MP4 file.
- Check its duration, resolution and frame rate in Import Video.
- Choose Frames to extract, then click Extract frames.
- Replica rejects blurred, poorly exposed or near-duplicate frames and selects views that cover the shot. Check how many it kept, then click Import N frames to create the project.
Replica may find fewer usable frames than you requested. Keep the original video and extracted-image folder: the images drive reconstruction, while the video supplies playback and the VFX plates, the frames used for compositing.
| Edition | Extraction limits |
|---|---|
| Free | Up to 50 frames from the first 20 seconds. Longer videos use only that section. |
| Lite / Pro | The licence does not cap duration or frame count. The panel's slider goes up to 500 frames. |
Reconstruct the scene
Open the session configuration and choose a preset. Input Loading defaults to Save Memory. Performance keeps decoded images in RAM and needs more memory. See Session configuration for the differences.
Click Start Session. Before solving the camera path, Replica needs the reconstructed camera poses and point cloud.
Solve the camera path
In the viewer's Camera track panel, click Compute camera track. Use Cancel to stop or Recompute to run it again after changing the reconstruction. Replica saves the result in camera_track.json inside the frames folder and reloads it when you reopen the project.
Show toggles the trajectory. Before exporting, read the calculation summary: some parts of the video may still have no reliable camera position.
Check video against the model
Click Play video on model to view the video with lens distortion corrected. Scrub the timeline and turn on Follow camera to look through the solved camera. Use the opacity slider to compare the video with the model, or turn Follow camera off to inspect the reconstruction from another position.
Playback stops where tracking has no reliable solution. When Next tracked frame appears, use it to move to the next solved section. Check these gaps even if the overall trajectory looks smooth.
Export for VFX
Once you have checked the track, choose USD for VFX in Export. The bundle includes the animated camera, full-resolution JPEG plates, a ProRes preview movie and video_track.json. If you have not computed and saved a track, it exports only the static photo cameras.
See USD for VFX for Blender import, timeline setup and gap handling.
Troubleshooting
The track button is disabled
Run reconstruction first. The calculation needs aligned camera poses and reconstructed points.
Tracking has gaps or loses alignment
Check image sharpness, overlap, surface detail and camera movement. Review the unsolved sections and reshoot if needed. Smoothing can make the path steadier, but the solver still needs enough image evidence to reconstruct it.
Export reports a calibration or frame-size problem
Check that the project still points to the original video. If you replaced, resized or recalibrated it, import and reconstruct it again.
An 8K project runs out of memory
Choose Save Memory, extract fewer frames or reduce reconstruction quality. A compressed video can be small on disk even when its decoded frames need a lot of RAM.