policy-endpoint: implement volume ducking

src/config-split/policy.lua.d/10-default-policy.lua

@@ -24,6 +24,9 @@ function default_policy.enable()
   -- API to access default nodes from scripts
   load_module("default-nodes-api")
 
+  -- API to access mixer controls, needed for volume ducking
+  load_module("mixer-api")
+
   -- Create sessions statically at startup
   load_script("static-sessions.lua", default_policy.sessions)
 

src/config-split/policy.lua.d/50-endpoints-config.lua

@@ -6,7 +6,7 @@ default_policy.policy.roles = {
   },
   ["Notification"] = {
     ["priority"] = 20,
-    ["action.default"] = "cork",
+    ["action.default"] = "duck",
     ["action.Notification"] = "mix",
   },
   ["Alert"] = {

src/config/config.lua.d/10-default-policy.lua

@@ -39,7 +39,7 @@ default_policy.policy = {
     },
     ["Notification"] = {
       ["priority"] = 20,
-      ["action.default"] = "cork",
+      ["action.default"] = "duck",
       ["action.Notification"] = "mix",
     },
     ["Alert"] = {
@@ -59,6 +59,12 @@ function default_policy.enable()
   load_module("si-standard-link")
   load_module("si-audio-endpoint")
 
+  -- API to access default nodes from scripts
+  load_module("default-nodes-api")
+
+  -- API to access mixer controls, needed for volume ducking
+  --load_module("mixer-api")
+
   -- Create sessions statically at startup
   load_script("static-sessions.lua", default_policy.sessions)
 

src/scripts/policy-endpoint-client-links.lua

@@ -7,6 +7,7 @@
 
 local config = ...
 config.roles = config.roles or {}
+config["duck.level"] = config["duck.level"] or 0.3
 
 function findRole(role)
   if role and not config.roles[role] then
@@ -40,6 +41,38 @@ function getAction(dominant_role, other_role)
       or "mix"
 end
 
+function restoreVolume(role, media_class)
+  if not mixer_api then return end
+
+  local ep = endpoints_om:lookup {
+    Constraint { "media.role", "=", role, type = "pw" },
+    Constraint { "media.class", "=", media_class, type = "pw" },
+  }
+
+  if ep and ep.properties["node.id"] then
+    Log.debug(ep, "restore role " .. role)
+    mixer_api:call("set-volume", ep.properties["node.id"], {
+      monitorVolume = 1.0,
+    })
+  end
+end
+
+function duck(role, media_class)
+  if not mixer_api then return end
+
+  local ep = endpoints_om:lookup {
+    Constraint { "media.role", "=", role, type = "pw" },
+    Constraint { "media.class", "=", media_class, type = "pw" },
+  }
+
+  if ep and ep.properties["node.id"] then
+    Log.debug(ep, "duck role " .. role)
+    mixer_api:call("set-volume", ep.properties["node.id"], {
+      monitorVolume = config["duck.level"],
+    })
+  end
+end
+
 function rescan()
   local links = {
     ["Audio/Source"] = {},
@@ -73,7 +106,7 @@ function rescan()
         ((l1.priority == l2.priority) and (l1.plugged > l2.plugged))
   end
 
-  for k, v in pairs(links) do
+  for media_class, v in pairs(links) do
     -- sort on priority and stream creation time
     table.sort(v, compareLinks)
 
@@ -90,8 +123,12 @@ function rescan()
           if not v[i].active then
             v[i].silink:activate(Feature.SessionItem.ACTIVE, pendingOperation())
           end
-        -- elseif action == "duck" then
-        --   TODO
+          restoreVolume(v[i].role, media_class)
+        elseif action == "duck" then
+          if not v[i].active then
+            v[i].silink:activate(Feature.SessionItem.ACTIVE, pendingOperation())
+          end
+          duck(v[i].role, media_class)
         else
           Log.warning("Unknown action: " .. action)
         end
@@ -100,6 +137,7 @@ function rescan()
       if not first_link.active then
         first_link.silink:activate(Feature.SessionItem.ACTIVE, pendingOperation())
       end
+      restoreVolume(first_link.role, media_class)
     end
   end
 end
@@ -134,3 +172,12 @@ silinks_om = ObjectManager {
 }
 silinks_om:connect("objects-changed", maybeRescan)
 silinks_om:activate()
+
+-- enable ducking if mixer-api is loaded
+mixer_api = Plugin("mixer-api")
+if mixer_api then
+  endpoints_om = ObjectManager {
+    Interest { type = "endpoint" },
+  }
+  endpoints_om:activate()
+end