diff --git a/frontend/pages/communication/chat.vue b/frontend/pages/communication/chat.vue
index a50c63b..8c23b01 100644
--- a/frontend/pages/communication/chat.vue
+++ b/frontend/pages/communication/chat.vue
@@ -24,6 +24,10 @@ const matrixCallTiles = ref([])
 const matrixCallMicEnabled = ref(true)
 const matrixCallCameraEnabled = ref(true)
 const matrixCallAudioContainer = ref(null)
+const matrixCallScreenShareEnabled = ref(false)
+const matrixCallStartedAt = ref(null)
+const matrixCallDurationNow = ref(Date.now())
+const matrixCallAnnouncementSent = ref(false)
 const roomCreateForm = ref({
   name: "",
   key: "",
@@ -39,6 +43,7 @@ const matrixMessageSending = ref(false)
 const matrixAutoRefreshActive = ref(false)
 const lastUpdated = ref(null)
 let matrixRefreshInterval = null
+let matrixCallDurationInterval = null
 let matrixMessagesRequestActive = false
 let matrixMembersRequestActive = false
 let matrixLiveKitRoom = null
@@ -75,6 +80,29 @@ const matrixCallTitle = computed(() =>
   matrixCallMode.value === "audio" ? "Audioanruf" : "Videokonferenz"
 )
 
+const matrixCallStateLabel = computed(() => {
+  const labels = {
+    connected: "Verbunden",
+    connecting: "Verbindet",
+    reconnecting: "Verbindung wird wiederhergestellt",
+    disconnected: "Getrennt"
+  }
+
+  return labels[String(matrixCallState.value).toLowerCase()] || matrixCallState.value
+})
+
+const matrixCallParticipantCount = computed(() => matrixCallTiles.value.length)
+
+const matrixCallDurationLabel = computed(() => {
+  if (!matrixCallStartedAt.value) return "00:00"
+
+  const durationSeconds = Math.max(0, Math.floor((matrixCallDurationNow.value - matrixCallStartedAt.value) / 1000))
+  const minutes = String(Math.floor(durationSeconds / 60)).padStart(2, "0")
+  const seconds = String(durationSeconds % 60).padStart(2, "0")
+
+  return `${minutes}:${seconds}`
+})
+
 const roomCreateKeyPreview = computed(() =>
   normalizeRoomKey(roomCreateForm.value.key || roomCreateForm.value.name)
 )
@@ -343,6 +371,11 @@ const syncRoomMembers = async () => {
 }
 
 const openMatrixCall = async (mode = "video") => {
+  if (matrixLiveKitRoom && matrixCallConnected.value) {
+    matrixCallOpen.value = true
+    return
+  }
+
   if (!canStartMatrixCall.value) {
     toast.add({
       title: "Besprechung kann noch nicht gestartet werden",
@@ -355,6 +388,7 @@ const openMatrixCall = async (mode = "video") => {
   matrixCallLoading.value = true
   matrixCallError.value = ""
   matrixCallOpen.value = true
+  matrixCallAnnouncementSent.value = false
 
   try {
     await leaveMatrixCall()
@@ -363,6 +397,7 @@ const openMatrixCall = async (mode = "video") => {
     })
     matrixCallSession.value = session
     await connectMatrixCall(session, { video: mode === "video" })
+    await announceMatrixCallStarted(mode)
   } catch (error) {
     matrixCallError.value = error?.data?.error || error?.message || "Verbindung fehlgeschlagen"
     toast.add({
@@ -377,12 +412,20 @@ const openMatrixCall = async (mode = "video") => {
 
 const getParticipantTile = (participant, local = false) => {
   const publications = participant.getTrackPublications?.() || []
-  const videoPublication = publications.find((publication) =>
-    publication.kind === Track.Kind.Video && publication.track
+  const screenSharePublication = publications.find((publication) =>
+    publication.kind === Track.Kind.Video &&
+    publication.source === Track.Source.ScreenShare &&
+    publication.track
+  )
+  const cameraPublication = publications.find((publication) =>
+    publication.kind === Track.Kind.Video &&
+    publication.source !== Track.Source.ScreenShare &&
+    publication.track
   )
   const audioPublication = publications.find((publication) =>
     publication.kind === Track.Kind.Audio && publication.track
   )
+  const videoPublication = screenSharePublication || cameraPublication
 
   return {
     id: local ? "local" : participant.sid || participant.identity,
@@ -390,6 +433,7 @@ const getParticipantTile = (participant, local = false) => {
     name: local ? "Du" : participant.name || participant.identity,
     local,
     speaking: participant.isSpeaking,
+    screenSharing: Boolean(screenSharePublication?.track),
     videoTrack: videoPublication?.track || null,
     audioTrack: audioPublication?.track || null,
     cameraEnabled: participant.isCameraEnabled,
@@ -428,11 +472,54 @@ const refreshMatrixCallTiles = async () => {
     ...Array.from(matrixLiveKitRoom.remoteParticipants.values()).map((participant) =>
       getParticipantTile(participant)
     )
-  ]
+  ].sort((a, b) => Number(b.screenSharing) - Number(a.screenSharing))
 
   await attachMatrixCallMedia()
 }
 
+const startMatrixCallDurationTimer = () => {
+  matrixCallStartedAt.value = Date.now()
+  matrixCallDurationNow.value = Date.now()
+
+  if (matrixCallDurationInterval) {
+    window.clearInterval(matrixCallDurationInterval)
+  }
+
+  matrixCallDurationInterval = window.setInterval(() => {
+    matrixCallDurationNow.value = Date.now()
+  }, 1000)
+}
+
+const stopMatrixCallDurationTimer = () => {
+  if (matrixCallDurationInterval) {
+    window.clearInterval(matrixCallDurationInterval)
+    matrixCallDurationInterval = null
+  }
+
+  matrixCallStartedAt.value = null
+  matrixCallDurationNow.value = Date.now()
+}
+
+const announceMatrixCallStarted = async (mode) => {
+  if (matrixCallAnnouncementSent.value || !activeRoom.value?.exists) return
+
+  matrixCallAnnouncementSent.value = true
+
+  try {
+    const message = await $api(`${activeRoomEndpoint.value}/messages`, {
+      method: "POST",
+      body: {
+        text: `${mode === "audio" ? "Audioanruf" : "Videokonferenz"} gestartet.`
+      }
+    })
+
+    mergeMatrixMessages([message])
+    await scrollMessagesToBottom()
+  } catch (error) {
+    matrixCallAnnouncementSent.value = false
+  }
+}
+
 const connectMatrixCall = async (session, { video = true } = {}) => {
   const room = new Room({
     adaptiveStream: true,
@@ -452,6 +539,7 @@ const connectMatrixCall = async (session, { video = true } = {}) => {
     RoomEvent.TrackMuted,
     RoomEvent.TrackUnmuted,
     RoomEvent.ActiveSpeakersChanged,
+    RoomEvent.LocalTrackSubscribed,
   ]
 
   for (const eventName of refreshEvents) {
@@ -461,11 +549,16 @@ const connectMatrixCall = async (session, { video = true } = {}) => {
   room.on(RoomEvent.ConnectionStateChanged, (state) => {
     matrixCallState.value = state
     matrixCallConnected.value = state === ConnectionState.Connected
+    if (state === ConnectionState.Connected && !matrixCallStartedAt.value) {
+      startMatrixCallDurationTimer()
+    }
   })
 
   room.on(RoomEvent.Disconnected, () => {
     matrixCallConnected.value = false
     matrixCallState.value = ConnectionState.Disconnected
+    matrixCallScreenShareEnabled.value = false
+    stopMatrixCallDurationTimer()
   })
 
   await room.connect(session.liveKitUrl, session.liveKitToken)
@@ -473,6 +566,10 @@ const connectMatrixCall = async (session, { video = true } = {}) => {
   await room.localParticipant.setCameraEnabled(video)
   matrixCallMicEnabled.value = true
   matrixCallCameraEnabled.value = video
+  matrixCallScreenShareEnabled.value = false
+  if (!matrixCallStartedAt.value) {
+    startMatrixCallDurationTimer()
+  }
   await refreshMatrixCallTiles()
 }
 
@@ -487,6 +584,9 @@ const leaveMatrixCall = async () => {
   matrixCallTiles.value = []
   matrixCallConnected.value = false
   matrixCallState.value = "disconnected"
+  matrixCallScreenShareEnabled.value = false
+  matrixCallAnnouncementSent.value = false
+  stopMatrixCallDurationTimer()
 }
 
 const closeMatrixCall = async () => {
@@ -494,6 +594,10 @@ const closeMatrixCall = async () => {
   matrixCallOpen.value = false
 }
 
+const minimizeMatrixCall = () => {
+  matrixCallOpen.value = false
+}
+
 const setMatrixCallVideoElement = (tileId, element) => {
   if (element) {
     matrixCallVideoElements.set(tileId, element)
@@ -522,6 +626,22 @@ const toggleMatrixCallCamera = async () => {
   await refreshMatrixCallTiles()
 }
 
+const toggleMatrixCallScreenShare = async () => {
+  if (!matrixLiveKitRoom) return
+
+  const enabled = !matrixCallScreenShareEnabled.value
+  try {
+    await matrixLiveKitRoom.localParticipant.setScreenShareEnabled(enabled)
+    matrixCallScreenShareEnabled.value = enabled
+    await refreshMatrixCallTiles()
+  } catch (error) {
+    toast.add({
+      title: "Bildschirmfreigabe konnte nicht geändert werden",
+      color: "error"
+    })
+  }
+}
+
 const loadRoomChat = async ({ silent = false, includeMembers = false } = {}) => {
   await loadRoomMessages({ silent })
 
@@ -625,6 +745,7 @@ onMounted(async () => {
 
 onBeforeUnmount(() => {
   stopMatrixAutoRefresh()
+  stopMatrixCallDurationTimer()
   leaveMatrixCall()
 })
 </script>
@@ -929,6 +1050,40 @@ onBeforeUnmount(() => {
         </UAlert>
       </div>
 
+      <div
+          v-if="matrixLiveKitRoom && matrixCallConnected"
+          class="flex shrink-0 flex-wrap items-center justify-between gap-3 border-b border-primary/20 bg-primary/10 px-4 py-3"
+      >
+        <div class="min-w-0">
+          <p class="truncate text-sm font-medium text-highlighted">
+            {{ matrixCallTitle }} läuft in {{ activeRoom.name }}
+          </p>
+          <p class="truncate text-xs text-muted">
+            {{ matrixCallParticipantCount }} Teilnehmer · {{ matrixCallDurationLabel }} · {{ matrixCallStateLabel }}
+          </p>
+        </div>
+        <div class="flex items-center gap-2">
+          <UButton
+              icon="i-heroicons-arrow-top-right-on-square"
+              color="primary"
+              variant="soft"
+              size="sm"
+              @click="matrixCallOpen = true"
+          >
+            Öffnen
+          </UButton>
+          <UButton
+              icon="i-heroicons-phone-x-mark"
+              color="error"
+              variant="soft"
+              size="sm"
+              @click="closeMatrixCall"
+          >
+            Auflegen
+          </UButton>
+        </div>
+      </div>
+
       <div
           ref="matrixMessagesViewport"
           class="min-h-0 flex-1 space-y-3 overflow-y-auto p-4 sm:p-5"
@@ -1133,6 +1288,24 @@ onBeforeUnmount(() => {
               >
                 {{ matrixCallCameraEnabled ? "Kamera an" : "Kamera aus" }}
               </UButton>
+              <UButton
+                  icon="i-heroicons-computer-desktop"
+                  color="neutral"
+                  :variant="matrixCallScreenShareEnabled ? 'soft' : 'outline'"
+                  :disabled="!matrixLiveKitRoom"
+                  @click="toggleMatrixCallScreenShare"
+              >
+                {{ matrixCallScreenShareEnabled ? "Freigabe an" : "Freigeben" }}
+              </UButton>
+              <UButton
+                  icon="i-heroicons-arrows-pointing-in"
+                  color="neutral"
+                  variant="ghost"
+                  :disabled="!matrixLiveKitRoom"
+                  @click="minimizeMatrixCall"
+              >
+                Minimieren
+              </UButton>
               <UButton
                   icon="i-heroicons-phone-x-mark"
                   color="error"
@@ -1174,14 +1347,15 @@ onBeforeUnmount(() => {
                 class="flex h-full flex-col"
             >
               <div class="flex shrink-0 items-center justify-between border-b border-default bg-default px-4 py-2 text-xs text-muted">
-                <span>{{ matrixCallSession?.liveKitRoomName || activeRoom.key }}</span>
-                <span>{{ matrixCallState }}</span>
+                <span>{{ matrixCallParticipantCount }} Teilnehmer · {{ matrixCallDurationLabel }}</span>
+                <span>{{ matrixCallStateLabel }}</span>
               </div>
               <div class="grid min-h-0 flex-1 auto-rows-fr gap-3 overflow-y-auto p-3 sm:grid-cols-2 xl:grid-cols-3">
                 <div
                     v-for="tile in matrixCallTiles"
                     :key="tile.id"
                     class="relative min-h-52 overflow-hidden rounded-lg bg-inverted text-inverted"
+                    :class="tile.speaking ? 'ring-2 ring-primary' : ''"
                 >
                   <video
                       v-if="tile.videoTrack"
@@ -1200,7 +1374,10 @@ onBeforeUnmount(() => {
                     </span>
                   </div>
                   <div class="absolute inset-x-0 bottom-0 flex items-center justify-between bg-black/55 px-3 py-2 text-sm text-white">
-                    <span class="truncate">{{ tile.name }}</span>
+                    <span class="truncate">
+                      {{ tile.name }}
+                      <span v-if="tile.screenSharing" class="ml-1 text-xs opacity-80">teilt Bildschirm</span>
+                    </span>
                     <div class="flex items-center gap-2">
                       <UIcon
                           :name="tile.microphoneEnabled ? 'i-heroicons-microphone' : 'i-heroicons-microphone'"