# Pearl REST API HDMI, SDI, and USB input settings

HDMI, SDI, and USB sources have their own settings blocks alongside the common `audio` and `video` blocks, and their capabilities vary by Pearl model.

*Applies to: Pearl-2, Pearl Mini, Pearl Nexus, Pearl Nano.*

**HDMI block** (`hdmi`):

| Field | Notes |
| --- | --- |
| `deinterlacing` | Converts an interlaced source signal to non-interlaced. Default `false` |
| `downscale_4k_to_fullhd` | Downscales a 4K UHD source to 1080p in hardware. Default `true` |
| `scaling` | Target resolution, such as `2560x1440` |
| `audio.mute` | Mute or unmute HDMI audio |
| `audio.delay` | HDMI audio delay, -300 to 300 ms. Default `0` |

**SDI block** (`sdi`) offers `downscale_4k_to_fullhd`, `scaling`, and the same `audio.mute` and `audio.delay` fields.

**Device differences**

- HDMI `deinterlacing` is supported on Pearl-2, Pearl Mini, and Pearl Nexus.
- HDMI `downscale_4k_to_fullhd` applies to the Pearl-2 HDMI 4K input.
- SDI `downscale_4k_to_fullhd` applies to Pearl-2.
- Pearl Nano does not support USB video input, so the USB camera and capture settings do not apply.
- Pearl Mini and Pearl Nexus capture video sources at a maximum resolution of 1920x1200, so `scaling` values above 1920×1200 do not apply to them.

**USB block** (`usb`). USB capture devices expose camera and capture controls:

| Field | Range | Default |
| --- | --- | --- |
| `capture_mode` | Resolution and frame rate, such as `1920x1080@30` | — |
| `brightness` | 0 to 100 | `50` |
| `contrast` | 0 to 100 | `50` |
| `saturation` | 0 to 100 | `0` |
| `sharpness` | 0 to 100 | `50` |
| `tilt` | -64 to 64 | `0` |
| `pan` | -64 to 64 | `0` |
| `power_line_frequency` | `0` disabled, `1` for 50 Hz, `2` for 60 Hz | `0` |
| `volume` | Capture volume as a percentage, 0 to 100 | `70` |

Setting the SDI scaling and audio delay on a Pearl Nano:

```json
{
  "video": { "nosignal": { "image": "", "timeout": 5 } },
  "sdi": { "scaling": "2560x1440", "audio": { "mute": true, "delay": 25 } }
}
```

On Pearl Nano, scaling above 1920×1200 requires the 4K feature add-on. On Pearl-2, 4K resolutions require the 4K feature add-on.

Use `PATCH` when adjusting one value, such as gain or mute, so the rest of the configuration is left untouched.

> product: pearl-family · topic: specs-ports · source: pearl-rest-api.md · updated: Oct 7, 2026