Pearl REST API common video and audio input settings

Input settings are read and written per source on one path, and several setting blocks are shared across input types rather than being specific to one.

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

Method and path	What it does
`GET /inputs/{sid}/settings`	Reads current settings
`PUT /inputs/{sid}/settings`	Replaces settings completely
`PATCH /inputs/{sid}/settings`	Updates only the fields you send

Settings blocks. A settings body carries only the blocks that apply to the source:

Block	Covers
`audio`	Common audio settings
`video`	Common video settings
`local_audio`	Analog and USB audio capture
`hdmi`	HDMI inputs
`sdi`	SDI inputs
`usb`	USB inputs
`srt`	SRT inputs
`rtsp`	RTSP inputs
`ndi`	NDI inputs
`web_graphics`	Web graphics inputs

Common audio block (audio):

delay — audio delay in milliseconds, from -300 to 300. Default 0.

Common video block (video):

Field	Notes
`nosignal.image`	Filename of the picture shown as the No Signal image
`nosignal.timeout`	Seconds in the No Signal state before the image appears. Default `5`
`force_full_color_range`	Converts limited RGB range (16–235) to full range (0–255). Default `true`
`hwaccel_decoding`	Use hardware acceleration for video decoding. Default `true`

Analog audio block (local_audio). This block covers analog and USB audio capture:

Field	Notes
`gain`	Capture gain. Units depend on the device — decibels or percentage
`mute`	Mute or unmute capture. Default `false`
`phantom_power`	Enable 48V phantom power. Default `false`
`input_type`	`XLR`, `RCA`, `XLR+RCA`, `3.5mm`, or `RCA+3.5mm`
`stereo_pair`	When `true`, both channels share gain and mute. Default `true`
`channels.channelA` / `channels.channelB`	Per-channel `gain` and `mute`, used when `stereo_pair` is `false`

Device differences

gain applies to USB audio, Pearl-2 analog audio, Pearl Mini XLR/TRS and RCA/3.5 mm analog audio, Pearl Nexus XLR/TRS and RCA/3.5 mm analog audio, and Pearl Nano analog audio.
mute applies to the sources above plus SDI audio and HDMI audio.
phantom_power applies to Pearl Mini XLR/TRS analog audio and Pearl Nexus XLR/TRS analog audio only.
input_type applies to Pearl-2 analog B (XLR/RCA), Pearl Mini RCA/3.5 mm, Pearl Nexus RCA/3.5 mm, and Pearl Nano analog audio.
stereo_pair and the per-channel channels block apply to Pearl-2 analog audio, Pearl Mini XLR/TRS, Pearl Nexus XLR/TRS, and Pearl Nano analog audio.

Setting per-channel gain on a Pearl Mini XLR/TRS input:

{
  "audio": { "delay": 1 },
  "local_audio": {
    "stereo_pair": false,
    "channels": {
      "channelA": { "gain": 40, "mute": true },
      "channelB": { "gain": 41, "mute": false }
    }
  }
}