## Start and Stop Recording
| Area | Element | Description |
|---|---|---|
| Controls | Start Recording / Stop Recording | Recording button. Shows Start Recording when idle (select to begin), Stop Recording while recording (select to stop). Dims briefly as the file writes |
| Episode Prefix | Filename prefix, default session\_ | |
| Save Folder | Save directory. Browse to choose a custom folder, Reset to restore the default. Shows Default when unset. See File Storage | |
| Frame Rate | Recording frame rate, fixed at Unlimited | |
| Channels | Channels to record, fixed at All | |
| Status | DURATION | Elapsed time, HH:MM:SS format (shown live while recording) |
| FILE SIZE | Current file size (B / KB / MB / GB) | |
| FRAMES | Total frames recorded | |
| DROP RATE | Data frame drop percentage | |
| CHANNELS | Active recording channels | |
| Episodes | Episodes | Lists saved MCAP files on the right of the panel, newest first, each with filename, creation time, and size. Click an entry to open the containing folder in your file manager |
| Metric | Good | Warning | Bad |
| - | - | - | - |
| **Frame Drop Rate** | \< 2% | 2%–5% | ≥ 5% |
| **Sync Offset** | \< 5 ms | 5–10 ms | ≥ 10 ms |
| **Sync Rate** | ≥ 95% | 90%–95% | \< 90% |
Each metric shows a color-coded indicator: green for Good, yellow for Warning, red for Bad. When a metric exceeds its threshold, a warning notification appears.
## File Storage
Recorded files are saved by default to:
```
Documents/WujiStudio/recordings/
```
Filename format: `{prefix}{YYYYMMDD}_{HHMMSS}_{milliseconds}.mcap`
For example, with the default prefix `session_`:
```
session_20250316_143025_123.mcap
```
Before recording, adjust two save settings in the **RECORDING** panel (locked while recording):
* **Filename prefix**: change **Episode Prefix**
* **Save folder**: select **Browse** next to **Save Folder** to choose a custom directory, or **Reset** to restore the default. When unset, the field shows **Default**, and files go to the default path above
## Data Playback
Open a local MCAP recording and replay it in the visualization panels to analyze captured data frame by frame.
### Open a Recording
1. In the Bottom bar, select the **PLAYER** tab
2. Select **Open File** (folder icon)
3. In the dialog, find the `.mcap` file to replay
4. Select **Open**
Replay one MCAP file at a time. Opening a file does not start playback automatically—select **Play** to begin.