Initial changes to support substreams

APIs/schemas/constraint_set.json

@@ -20,6 +20,13 @@
       "description": "This value indicates whether a Constraint Set is available to use immediately (true) or whether this is an offline capability which can be activated via some unspecified configuration mechanism (false). When the attribute is omitted its value is assumed to be true.",
       "type": "boolean",
       "default": true
+    },
+    "urn:x-nmos:substreams": {
+      "description": "This exposes any substream constraints.",
+      "type": "array",
+      "items": {
+        "$ref": "substream_constraints.json"
+      }
     }
   },
   "patternProperties": {

APIs/schemas/substream_constraints.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "description": "Describes substream constraints",
+  "title": "Constraint Set",
+  "type": "object",
+  "minProperties": 1,
+  "properties": {
+    "description": {
+      "description": "Substream group description",
+      "type": "string"
+    },
+    "format": {
+      "description": "Substream format",
+      "type": "string",
+      "enum": ["video", "audio", "data"]
+    },
+    "count": {
+      "$ref": "param_constraint_number.json"
+    },
+    "constraint_sets": {
+      "description": "Substream constraint sets",
+      "type": "array",
+      "items": {
+        "$ref": "constraint_set.json"
+      }
+    }
+  }
+}

docs/Examples.md

@@ -236,3 +236,59 @@ For example, Type N receivers can be expected to correctly receive a stream orig
 
 [TR-05]: https://www.videoservicesforum.org/download/technical_recommendations/VSF_TR-05_2018-06-23.pdf
 "VSF TR-05: Essential Formats and Descriptions for Interoperability of SMPTE ST 2110-20 Video Signals"
+
+### Substreams
+
+The following example shows a MUX MPEG 2 transport stream receiver exposing substream constraints.
+
+```json
+{
+  "id": "9dd002e2-76a0-4edc-88ef-7d4aff4b2d26",
+  "transport": "rtp",
+  "format": "mux",
+  "caps": {
+    "media_types": [
+      "video/MP2T"
+    ],
+    "constraint_sets": [
+      {
+        "urn:x-nmos:substreams": [
+          {
+            "description": "hi-res",
+            "format": "video",
+            "count": {
+              "enum": [
+                1
+              ]
+            },
+            "constraint_sets": [...]
+          },
+          {
+            "description": "proxy",
+            "format": "video",
+            "count": {
+              "minimum": 0,
+              "maximum": 1
+            },
+            "constraint_sets": [...]
+          },
+          {
+            "format": "audio",
+            "count": {
+              "enum": [
+                0,
+                2,
+                4
+              ]
+            },
+            "constraint_sets": [...]
+          }
+        ]
+      },
+      {
+        "urn:x-nmos:substreams": [...]
+      }
+    ]
+  }
+}
+```