Add agent-capbilitiy type and agent-info.capabilities field.

index.bs

@@ -360,13 +360,46 @@ The agent-info-response message contains the following properties:
     the device.  This is used mainly for debugging purposes, but may be
     displayed to the user of the requesting agent.
 
-: receives-audio (optional)
-:: The agent has to indicate that it supports audio. If false
-    or not included, it is assumed audio content is not supported.
-
-: receives-video (optional)
-:: The agent has to indicate that it supports video . If false
-    or not included, it is assumed video content is not supported.
+: capabilities (required)
+:: The contorol protocols, roles, and media types the agent support.
+    Presence indicates capability and absence indicates lack of
+    capability.  Capabilities should should affect how an agent is
+    presented to a user, such as drawing a different icon depending on
+    the media types it supports.
+
+The various capabilities have the following meanings:
+
+: receive-audio
+:: The agent can generally receive audio for the control protocols it
+    supports.  Each control protocol can have more specific capability
+    mechanisms, such as support for specific URLs in the presentation
+    protocol.
+
+: receive-video
+:: The agent can generally receive video for the control protocols it
+    supports.  Each control protocol can have more specific capability
+    mechanisms, such as support for specific URLs in the presentation
+    protocol.
+
+: receive-presentation
+:: The agent can receive presentations using the presentation protocol.
+
+: control-presentation
+:: The agent can control presentations using the presentation protocol.
+
+: receive-remote-playback
+:: The agent can receive remote playback using the remote playback
+    protocol.
+
+: control-remote-playback
+:: The agent can control remote playback using the remote playback
+    protocol.
+
+: receive-streaming
+:: The agent can receiving streaming using the streaming protocol.
+
+: send-streaming
+:: The agent can send streaming using the streaming protocol.
 
 
 Listening agents act as QUIC clients.  Advertising agents act as QUIC servers.

messages_appendix.cddl

@@ -9,11 +9,24 @@ agent-info-response = {
   1: agent-info ; agent-info
 }
 
+agent-capability = &(
+  receive-audio: 1
+  receive-video: 2
+
+  receive-presentation: 2
+  control-presentation: 3
+
+  receive-remote-playback: 4
+  control-remote-playback: 5
+
+  receive-streaming: 6
+  send-streaming: 7
+)
+
 agent-info = {
   0: text ; display-name
   1: text ; model-name
-  ? 2: bool ; receives-audio
-  ? 3: bool ; receives-video
+  2: [* agent-capabilitiy] ; capabilities
 }
 
 ; type key 102