What is motion.json and when should I attach it?
A motion.json file contains motion sensor data — like pitch, roll, yaw, and acceleration — recorded alongside a video. Smooth Operator can use this data to create realistic, physics-based camera movements that match the original camera motion.
Do I need motion.json?
No, it is completely optional. Smooth Operator works great without motion data. You can create camera moves manually using anchors and move blocks, or use AI features to generate movements.
Motion.json is helpful when:
- You recorded video with a device that captures motion data (such as a gimbal or a custom camera rig).
- You want Smooth Operator to replicate or enhance the original camera movement.
- You want to use the Auto-Process Wizard to automatically generate camera moves from the data.
How Smooth Operator finds motion data
The app can detect motion data in three ways:
- Auto-detection: If the video file has a matching .json file with the same name in the same folder, the app finds it automatically.
- Bundle import: If you select a folder containing both "video.mov" and "motion.json," the app detects them as a bundle.
- Manual attachment: During import, tap "Attach motion.json" and select any .json file.
What is inside a motion.json file?
The file contains motion sensor samples recorded over time. Each sample has:
- A timestamp (when it was recorded)
- Attitude data (pitch, roll, yaw — the device's orientation)
- Rotation rate (how fast the device was rotating)
- Acceleration data (how the device was moving)
You do not need to understand or edit this file. Smooth Operator reads it automatically.
What happens after importing with motion data
When motion data is detected, the Auto-Process Wizard opens after import. This wizard:
- Shows how many motion samples were found (e.g., "1,234 samples recorded").
- Lets you choose a camera motion style from Presets.
- Generates anchors and camera moves based on the motion data and your chosen style.
You can skip the wizard and edit manually if you prefer.
What if my motion.json doesn't work?
- The file must be valid JSON in the format Smooth Operator expects. If the format is wrong, it is silently ignored — the project opens without the Auto-Process Wizard and without an error message.
- Make sure the motion.json is in the same folder as the video file for auto-detection.
- If auto-detection fails, try attaching the file manually during import.