opendigitaltwins-dtdl

Onvif extension

The DTDL Onvif extension facilitates the translation of ONVIF WSDL definitions into DTDL. The request and response schemas defined in the ONVIF specification are deeply nested. The higher limits provided by the Onvif extension permit the direct translation of WSDL definitions without the need for flattening. In addition, the increased length limit on values of the DTDL “description” property permits directly copying WSDL descriptions without the need for abridging or summarizing.

Revised global limits

Revised property limits

The following tables itemize the types and properties whose limits are increased by the extension.

Array

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters
elementSchema	The data type of each element in the Array, which is an instance of Schema.	max depth of 8 levels	max depth of 24 levels

Command

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

CommandRequest

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

CommandResponse

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Component

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Enum

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

EnumValue

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Field

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters
schema	The data type of the element, which is an instance of Schema.	max depth of 8 levels when Field is the value of Object fields	max depth of 24 levels when Field is the value of Object fields

Interface

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Map

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

MapKey

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

MapValue

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters
schema	The data type of the element, which is an instance of Schema.	max depth of 8 levels when MapValue is the value of Map mapValue	max depth of 24 levels when MapValue is the value of Map mapValue

Object

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Property

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Relationship

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Telemetry

Property	Description	Standard limits	Onvif limits
description	A localizable description for display.	max 512 characters	max 4096 characters

Onvif examples

The following example is a highly abridged excerpt from a translation of the ONVIF standard into DTDL. This model is valid despite having a nested schema whose depth exceeds the standard DTDL limit.

{
  "@context": [
    "dtmi:dtdl:context;4#limitless",
    "dtmi:dtdl:limits:onvif;1"
  ],
  "@id": "dtmi:onvif:media;1",
  "@type": "Interface",
  "schemas": [
    {
      "@id": "dtmi:onvif:media:GetProfilesResponse;1",
      "@type": "Object",
      "fields": [
        {
          "name": "Profiles",
          "description": "List of profiles",
          "schema": {
            "@type": "Array",
            "elementSchema": "dtmi:onvif:media:Profile;1"
          }
        }
      ]
    },
    {
      "@id": "dtmi:onvif:media:Profile;1",
      "@type": "Object",
      "fields": [
        {
          "name": "MetadataConfiguration",
          "description": "Optional configuration of the metadata stream.",
          "schema": "dtmi:onvif:media:MetadataConfiguration;1"
        }
      ]
    },
    {
      "@id": "dtmi:onvif:media:MetadataConfiguration;1",
      "@type": "Object",
      "fields": [
        {
          "name": "AnalyticsEngineConfiguration",
          "schema": "dtmi:onvif:media:AnalyticsEngineConfiguration;1"
        }
      ]
    },
    {
      "@id": "dtmi:onvif:media:AnalyticsEngineConfiguration;1",
      "@type": "Object",
      "fields": [
        {
          "name": "AnalyticsModule",
          "schema": {
            "@type": "Array",
            "elementSchema": "dtmi:onvif:media:Config;1"
          }
        }
      ]
    },
    {
      "@id": "dtmi:onvif:media:Config;1",
      "@type": "Object",
      "fields": [
        {
          "name": "Parameters",
          "description": "List of configuration parameters as defined in the corresponding description.",
          "schema": "dtmi:onvif:media:ItemList;1"
        }
      ]
    },
    {
      "@id": "dtmi:onvif:media:ItemList;1",
      "@type": "Object",
      "fields": [
        {
          "name": "SimpleItem",
          "description": "Value name pair as defined by the corresponding description.",
          "schema": {
            "@type": "Array",
            "elementSchema": "dtmi:onvif:media:SimpleItem;1"
          }
        }
      ]
    },
    {
      "@id": "dtmi:onvif:media:SimpleItem;1",
      "@type": "Object",
      "fields": [
        {
          "name": "Name",
          "description": "Item name.",
          "schema": "string"
        },
        {
          "name": "Value",
          "description": "Item value. The type is defined in the corresponding description.",
          "schema": "string"
        }
      ]
    }
  ],
  "contents": [
    {
      "@type": "Command",
      "name": "GetProfiles",
      "response": {
        "name": "GetProfilesResponse",
        "schema": "dtmi:onvif:media:GetProfilesResponse;1"
      }
    }
  ]
}

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