Show information about absent RTMP stream.

Telegram/Resources/langs/lang.strings

@@ -2364,8 +2364,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_group_call_unpinned_camera" = "{user}'s video is unpinned.";
 "lng_group_call_unpinned_screen" = "{user}'s screencast is unpinned.";
 "lng_group_call_sure_screencast" = "{user} is screensharing. This action will make your screencast pinned for all participants.";
-"lng_group_call_pinned_on_top" = "Live stream pinned on top.";
+"lng_group_call_pinned_on_top" = "Live stream is pinned on top.";
-"lng_group_call_unpinned_on_top" = "Live stream unpinned from top.";
+"lng_group_call_unpinned_on_top" = "Live stream is unpinned from top.";
 "lng_group_call_recording_start_sure" = "Participants will see the chat is being recorded.";
 "lng_group_call_recording_stop_sure" = "Do you want to stop recording this chat?";
 "lng_group_call_recording_start_field" = "Recording Title";
@@ -2383,6 +2383,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_group_call_title_changed_channel" = "Live stream title changed to {title}";
 "lng_group_call_join_as_changed" = "Members of this voice chat will now see you as {name}";
 "lng_group_call_join_as_changed_channel" = "Members of this live stream will now see you as {name}";
+"lng_group_call_no_stream_admin" = "Oops! Telegram doesn't see any stream coming from your streaming app. Please make sure you entered the right Server URL and Stream Key in your app..";
+"lng_group_call_no_stream" = "{group} is currently not broadcasting live stream data to Telegram.";
 
 "lng_menu_start_group_call" = "Start video chat";
 "lng_menu_start_group_call_scheduled" = "Schedule video chat";

Telegram/SourceFiles/calls/group/calls_group_panel.cpp

@@ -795,6 +795,7 @@ void Panel::setupMembers() {
 
 	_members->show();
 
+	setupEmptyRtmp();
 	refreshControlsBackground();
 	raiseControls();
 
@@ -1596,6 +1597,38 @@ void Panel::updateButtonsStyles() {
 		: st::groupCallHangup);
 }
 
+void Panel::setupEmptyRtmp() {
+	_call->emptyRtmpValue(
+	) | rpl::start_with_next([=](bool empty) {
+		if (!empty) {
+			_emptyRtmp.destroy();
+			return;
+		} else if (_emptyRtmp) {
+			return;
+		}
+		auto text = _call->rtmpUrl().isEmpty()
+			? tr::lng_group_call_no_stream(
+				lt_group,
+				rpl::single(_peer->name))
+			: tr::lng_group_call_no_stream_admin();
+		_emptyRtmp.create(
+			widget(),
+			std::move(text),
+			st::groupCallVideoLimitLabel);
+		widget()->sizeValue(
+		) | rpl::start_with_next([=](QSize size) {
+			const auto width = std::min(
+				size.width() - st::groupCallWidth / 10,
+				st::groupCallWidth);
+			_emptyRtmp->resizeToWidth(width);
+			_emptyRtmp->move(
+				(size.width() - _emptyRtmp->width()) / 2,
+				(size.height() - _emptyRtmp->height()) / 3);
+		}, _emptyRtmp->lifetime());
+	}, lifetime());
+
+}
+
 void Panel::refreshControlsBackground() {
 	if (!_members) {
 		return;

Telegram/SourceFiles/calls/group/calls_group_panel.h

@@ -161,6 +161,7 @@ private:
 		std::optional<bool> overrideWideMode = std::nullopt);
 	void refreshTopButton();
 	void createPinOnTop();
+	void setupEmptyRtmp();
 	void toggleWideControls(bool shown);
 	void updateWideControlsVisibility();
 	[[nodiscard]] bool videoButtonInNarrowMode() const;
@@ -225,6 +226,7 @@ private:
 	object_ptr<Ui::RpWidget> _countdown = { nullptr };
 	std::shared_ptr<Ui::GroupCallScheduledLeft> _countdownData;
 	object_ptr<Ui::FlatLabel> _startsWhen = { nullptr };
+	object_ptr<Ui::FlatLabel> _emptyRtmp = { nullptr };
 	ChooseJoinAsProcess _joinAsProcess;
 	std::optional<QRect> _lastSmallGeometry;
 	std::optional<QRect> _lastLargeGeometry;