Add UI for simulcast control.

static/galene.css

@@ -771,6 +771,12 @@ h1 {
     margin-right: 0.4em;
 }
 
+#simulcastselect {
+    width: 8em;
+    text-align-last: center;
+    margin-right: 0.4em;
+}
+
 #requestselect {
     width: 8em;
     text-align-last: center;

static/galene.html

@@ -208,6 +208,15 @@
             </select>
           </form>
 
+          <form id="simulcastform">
+            <label for="simulcastselect" class="sidenav-label-first">Simulcast:</label>
+            <select id="simulcastselect" class="select select-inline">
+              <option value="off">off</option>
+              <option value="auto" selected>auto</option>
+              <option value="on">on</option>
+            </select>
+          </form>
+
           <form id="requestform">
             <label for="requestselect" class="sidenav-label">Receive:</label>
             <select id="requestselect" class="select select-inline">

static/galene.js

@@ -78,7 +78,7 @@ function getUserPass() {
  * @property {boolean} [localMute]
  * @property {string} [video]
  * @property {string} [audio]
- * @property {boolean} [simulcast]
+ * @property {string} [simulcast]
  * @property {string} [send]
  * @property {string} [request]
  * @property {boolean} [activityDetection]
@@ -229,6 +229,13 @@ function reflectSettings() {
         store = true;
     }
 
+    if(settings.hasOwnProperty('simulcast')) {
+        getSelectElement('simulcastselect').value = settings.simulcast
+    } else {
+        settings.simulcast = getSelectElement('simulcastselect').value;
+        store = true;
+    }
+
     if(settings.hasOwnProperty('blackboardMode')) {
         getInputElement('blackboardbox').checked = settings.blackboardMode;
     } else {
@@ -538,6 +545,17 @@ getSelectElement('sendselect').onchange = async function(e) {
     }
 };
 
+getSelectElement('simulcastselect').onchange = async function(e) {
+    if(!(this instanceof HTMLSelectElement))
+        throw new Error('Unexpected type for this');
+    updateSettings({simulcast: this.value});
+    let t = getMaxVideoThroughput();
+    for(let id in serverConnection.up) {
+        let c = serverConnection.up[id];
+        await setMaxVideoThroughput(c, t);
+    }
+};
+
 /**
  * @param {string} what
  * @returns {Object<string,Array<string>>}
@@ -1042,11 +1060,16 @@ const simulcastRate = 100000;
  * @returns {boolean}
  */
 function doSimulcast() {
-    if(!getSettings().simulcast)
+    switch(getSettings().simulcast) {
+    case 'on':
+        return true;
+    case 'off':
         return false;
+    default:
         let bps = getMaxVideoThroughput();
         return bps <= 0 || bps >= 2 * simulcastRate;
     }
+}
 
 /**
  * Sets up c to send the given stream.  Some extra parameters are stored