diff --git a/lib/matrix.dart b/lib/matrix.dart
index 140b8e5c..2627578e 100644
--- a/lib/matrix.dart
+++ b/lib/matrix.dart
@@ -37,6 +37,7 @@ export 'src/utils/http_timeout.dart';
 export 'src/client.dart';
 export 'src/event.dart';
 export 'src/room.dart';
+export 'src/voip_content.dart';
 export 'src/timeline.dart';
 export 'src/user.dart';
 export 'src/database/database_api.dart';
diff --git a/lib/src/room.dart b/lib/src/room.dart
index 08bbcabb..c935aa03 100644
--- a/lib/src/room.dart
+++ b/lib/src/room.dart
@@ -28,6 +28,7 @@ import 'client.dart';
 import 'event.dart';
 import 'timeline.dart';
 import 'user.dart';
+import 'voip_content.dart';
 import 'utils/crypto/encrypted_file.dart';
 import 'utils/event_update.dart';
 import 'utils/markdown.dart';
@@ -56,153 +57,6 @@ const Map<HistoryVisibility, String> _historyVisibilityMap = {
   HistoryVisibility.worldReadable: 'world_readable',
 };
 
-class CallReplacesTarget {
-  String id;
-  String display_name;
-  String avatar_url;
-
-  CallReplacesTarget();
-  factory CallReplacesTarget.fromJson(Map<String, dynamic> json) {
-    return CallReplacesTarget()
-      ..id = json['id'].toString()
-      ..display_name = json['display_name'].toString()
-      ..avatar_url = json['avatar_url'].toString();
-  }
-  Map<String, dynamic> toJson() {
-    return {
-      if (id != null) 'id': id,
-      if (display_name != null) 'display_name': display_name,
-      if (avatar_url != null) 'avatar_url': avatar_url,
-    };
-  }
-}
-
-/// MSC2747: VoIP call transfers
-/// https://github.com/matrix-org/matrix-doc/pull/2747
-class CallReplaces {
-  String replacement_id;
-  CallReplacesTarget target_user;
-  String create_call;
-  String await_call;
-  String target_room;
-
-  CallReplaces();
-  factory CallReplaces.fromJson(Map<String, dynamic> json) {
-    return CallReplaces()
-      ..replacement_id = json['replacement_id'].toString()
-      ..create_call = json['create_call'].toString()
-      ..await_call = json['await_call'].toString()
-      ..target_room = json['target_room'].toString()
-      ..target_user = CallReplacesTarget.fromJson(json['target_user']);
-  }
-
-  Map<String, dynamic> toJson() {
-    return {
-      if (replacement_id != null) 'replacement_id': replacement_id,
-      if (target_user != null) 'target_user': target_user.toJson(),
-      if (create_call != null) 'create_call': create_call,
-      if (await_call != null) 'await_call': await_call,
-      if (target_room != null) 'target_room': target_room,
-    };
-  }
-}
-
-// TODO: Change to "sdp_stream_metadata" when MSC3077 is merged
-const String sdpStreamMetadataKey = 'org.matrix.msc3077.sdp_stream_metadata';
-
-/// https://github.com/matrix-org/matrix-doc/blob/dbkr/msc2747/proposals/2747-voip-call-transfer.md#capability-advertisment
-/// https://github.com/matrix-org/matrix-doc/blob/dbkr/msc2746/proposals/2746-reliable-voip.md#add-dtmf
-class CallCapabilities {
-  bool transferee;
-  bool dtmf;
-  CallCapabilities();
-  factory CallCapabilities.fromJson(Map<String, dynamic> json) {
-    return CallCapabilities()
-      ..dtmf = json['m.call.dtmf'] as bool ?? false
-      ..transferee = json['m.call.transferee'] as bool ?? false;
-  }
-  Map<String, dynamic> toJson() {
-    return {
-      if (transferee != null) 'm.call.transferee': transferee,
-      if (dtmf != null) 'm.call.dtmf': dtmf,
-    };
-  }
-}
-
-/// MSC3077: Support for multi-stream VoIP
-/// https://github.com/matrix-org/matrix-doc/pull/3077
-///
-/// MSC3291: Muting in VoIP calls
-/// https://github.com/SimonBrandner/matrix-doc/blob/msc/muting/proposals/3291-muting.md
-///
-/// This MSC proposes adding an sdp_stream_metadata field
-/// to the events containing a session description i.e.:
-/// m.call.invite, m.call.answer, m.call.negotiate
-///
-class SDPStreamPurpose {
-  // SDPStreamMetadataPurpose
-  String purpose;
-  bool audio_muted;
-  bool video_muted;
-
-  SDPStreamPurpose();
-  factory SDPStreamPurpose.fromJson(Map<String, dynamic> json) {
-    return SDPStreamPurpose()
-      ..audio_muted = json['audio_muted'] as bool ?? false
-      ..video_muted = json['video_muted'] as bool ?? false
-      ..purpose = json['purpose'] as String;
-  }
-
-  Map<String, dynamic> toJson() {
-    return {
-      'purpose': purpose,
-      if (audio_muted != null) 'audio_muted': audio_muted,
-      if (video_muted != null) 'video_muted': video_muted,
-    };
-  }
-}
-
-class SDPStreamMetadataPurpose {
-  static String Usermedia = 'm.usermedia';
-  static String Screenshare = 'm.screenshare';
-}
-
-class SDPStreamMetadata {
-  Map<String, SDPStreamPurpose> sdpStreamMetadatas;
-  SDPStreamMetadata(this.sdpStreamMetadatas);
-
-  factory SDPStreamMetadata.fromJson(Map<String, dynamic> json) {
-    return SDPStreamMetadata(json
-        .map((key, value) => MapEntry(key, SDPStreamPurpose.fromJson(value))));
-  }
-  Map<String, dynamic> toJson() {
-    return sdpStreamMetadatas
-        .map((key, value) => MapEntry(key, value.toJson()));
-  }
-}
-
-/// MSC3086: Asserted identity on VoIP calls
-/// https://github.com/matrix-org/matrix-doc/pull/3086
-class AssertedIdentity {
-  String id;
-  String displayName;
-  String avatarUrl;
-  AssertedIdentity();
-  factory AssertedIdentity.fromJson(Map<String, dynamic> json) {
-    return AssertedIdentity()
-      ..displayName = json['display_name'] as String
-      ..id = json['id'] as String
-      ..avatarUrl = json['avatar_url'] as String;
-  }
-  Map<String, dynamic> toJson() {
-    return {
-      if (displayName != null) 'display_name': displayName,
-      if (id != null) 'id': id,
-      if (avatarUrl != null) 'avatar_url': avatarUrl,
-    };
-  }
-}
-
 const String messageSendingStatusKey =
     'com.famedly.famedlysdk.message_sending_status';
 
diff --git a/lib/src/voip_content.dart b/lib/src/voip_content.dart
new file mode 100644
index 00000000..887824c7
--- /dev/null
+++ b/lib/src/voip_content.dart
@@ -0,0 +1,148 @@
+// @dart=2.9
+class CallReplacesTarget {
+  String id;
+  String display_name;
+  String avatar_url;
+
+  CallReplacesTarget();
+  factory CallReplacesTarget.fromJson(Map<String, dynamic> json) {
+    return CallReplacesTarget()
+      ..id = json['id'].toString()
+      ..display_name = json['display_name'].toString()
+      ..avatar_url = json['avatar_url'].toString();
+  }
+  Map<String, dynamic> toJson() {
+    return {
+      if (id != null) 'id': id,
+      if (display_name != null) 'display_name': display_name,
+      if (avatar_url != null) 'avatar_url': avatar_url,
+    };
+  }
+}
+
+/// MSC2747: VoIP call transfers
+/// https://github.com/matrix-org/matrix-doc/pull/2747
+class CallReplaces {
+  String replacement_id;
+  CallReplacesTarget target_user;
+  String create_call;
+  String await_call;
+  String target_room;
+
+  CallReplaces();
+  factory CallReplaces.fromJson(Map<String, dynamic> json) {
+    return CallReplaces()
+      ..replacement_id = json['replacement_id'].toString()
+      ..create_call = json['create_call'].toString()
+      ..await_call = json['await_call'].toString()
+      ..target_room = json['target_room'].toString()
+      ..target_user = CallReplacesTarget.fromJson(json['target_user']);
+  }
+
+  Map<String, dynamic> toJson() {
+    return {
+      if (replacement_id != null) 'replacement_id': replacement_id,
+      if (target_user != null) 'target_user': target_user.toJson(),
+      if (create_call != null) 'create_call': create_call,
+      if (await_call != null) 'await_call': await_call,
+      if (target_room != null) 'target_room': target_room,
+    };
+  }
+}
+
+// TODO: Change to "sdp_stream_metadata" when MSC3077 is merged
+const String sdpStreamMetadataKey = 'org.matrix.msc3077.sdp_stream_metadata';
+
+/// https://github.com/matrix-org/matrix-doc/blob/dbkr/msc2747/proposals/2747-voip-call-transfer.md#capability-advertisment
+/// https://github.com/matrix-org/matrix-doc/blob/dbkr/msc2746/proposals/2746-reliable-voip.md#add-dtmf
+class CallCapabilities {
+  bool transferee;
+  bool dtmf;
+  CallCapabilities();
+  factory CallCapabilities.fromJson(Map<String, dynamic> json) {
+    return CallCapabilities()
+      ..dtmf = json['m.call.dtmf'] as bool ?? false
+      ..transferee = json['m.call.transferee'] as bool ?? false;
+  }
+  Map<String, dynamic> toJson() {
+    return {
+      if (transferee != null) 'm.call.transferee': transferee,
+      if (dtmf != null) 'm.call.dtmf': dtmf,
+    };
+  }
+}
+
+/// MSC3077: Support for multi-stream VoIP
+/// https://github.com/matrix-org/matrix-doc/pull/3077
+///
+/// MSC3291: Muting in VoIP calls
+/// https://github.com/SimonBrandner/matrix-doc/blob/msc/muting/proposals/3291-muting.md
+///
+/// This MSC proposes adding an sdp_stream_metadata field
+/// to the events containing a session description i.e.:
+/// m.call.invite, m.call.answer, m.call.negotiate
+///
+class SDPStreamPurpose {
+  // SDPStreamMetadataPurpose
+  String purpose;
+  bool audio_muted;
+  bool video_muted;
+
+  SDPStreamPurpose();
+  factory SDPStreamPurpose.fromJson(Map<String, dynamic> json) {
+    return SDPStreamPurpose()
+      ..audio_muted = json['audio_muted'] as bool ?? false
+      ..video_muted = json['video_muted'] as bool ?? false
+      ..purpose = json['purpose'] as String;
+  }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'purpose': purpose,
+      if (audio_muted != null) 'audio_muted': audio_muted,
+      if (video_muted != null) 'video_muted': video_muted,
+    };
+  }
+}
+
+class SDPStreamMetadataPurpose {
+  static String Usermedia = 'm.usermedia';
+  static String Screenshare = 'm.screenshare';
+}
+
+class SDPStreamMetadata {
+  Map<String, SDPStreamPurpose> sdpStreamMetadatas;
+  SDPStreamMetadata(this.sdpStreamMetadatas);
+
+  factory SDPStreamMetadata.fromJson(Map<String, dynamic> json) {
+    return SDPStreamMetadata(json
+        .map((key, value) => MapEntry(key, SDPStreamPurpose.fromJson(value))));
+  }
+  Map<String, dynamic> toJson() {
+    return sdpStreamMetadatas
+        .map((key, value) => MapEntry(key, value.toJson()));
+  }
+}
+
+/// MSC3086: Asserted identity on VoIP calls
+/// https://github.com/matrix-org/matrix-doc/pull/3086
+class AssertedIdentity {
+  String id;
+  String displayName;
+  String avatarUrl;
+  AssertedIdentity();
+  factory AssertedIdentity.fromJson(Map<String, dynamic> json) {
+    return AssertedIdentity()
+      ..displayName = json['display_name'] as String
+      ..id = json['id'] as String
+      ..avatarUrl = json['avatar_url'] as String;
+  }
+  Map<String, dynamic> toJson() {
+    return {
+      if (displayName != null) 'display_name': displayName,
+      if (id != null) 'id': id,
+      if (avatarUrl != null) 'avatar_url': avatarUrl,
+    };
+  }
+}
+