Adding devices

Devices are specified in JSON files. As devices can be user-defined, there is no need to recompile the code or wait for new releases to use Overwitch with new devices of the same type.

Overwitch first searches a device in all the files with json extension in the ~/.config/overwitch/devices.d directory, where each file contains a single JSON object; then into the user defined file ~/.config/overwitch/devices.json, which is a JSON array of these objects; and finally into the devices file distributed with Overwitch, which is a JSON array too.

JSON format

This example is a self-explanatory JSON object for a device.

{
  "pid": 2899,
  "name": "Analog Heat +FX",
  "type": 2,
  "input_tracks": [
    {
      "name": "Main L Input",
      "size": 4
    },
    {
      "name": "Main R Input",
      "size": 4
    },
    {
      "name": "FX Send L",
      "size": 4
    },
    {
      "name": "FX Send R",
      "size": 4
    }
  ],
  "output_tracks": [
    {
      "name": "Main L",
      "size": 4
    },
    {
      "name": "Main R",
      "size": 4
    },
    {
      "name": "FX Return L",
      "size": 4
    },
    {
      "name": "FX Return R",
      "size": 4
    }
  ]
}

Notice that there are 3 types of devices, depending on the transfer type and how many bytes are used to store samples in the USB blocks.

• Type 1 (isochronous transfers) is reserved for Analog Rytm MKI and Analog Form MKI and Keys.
• Type 2 (interrupt transfers) uses 4 bytes integers.
• Type 3 (interrupt transfers) uses 3 bytes integers. Note that some tracks might use 4 bytes to store the samples even though the actual samples are only 3 bytes.