Fix joining calls without audio or video inputs (#9486)

The lobby view was requesting a stream with both video and audio, even if the system lacked video or audio devices. Requesting one of audio or video is enough to get all device labels.

src/components/views/voip/CallView.tsx

@@ -33,7 +33,7 @@ import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import AppTile from "../elements/AppTile";
 import { _t } from "../../../languageHandler";
 import { useAsyncMemo } from "../../../hooks/useAsyncMemo";
-import MediaDeviceHandler, { MediaDeviceKindEnum } from "../../../MediaDeviceHandler";
+import MediaDeviceHandler from "../../../MediaDeviceHandler";
 import { CallStore } from "../../../stores/CallStore";
 import IconizedContextMenu, {
  IconizedContextMenuOption,
@@ -141,36 +141,38 @@ export const Lobby: FC<LobbyProps> = ({ room, joinCallButtonDisabled, joinCallBu
  }, [videoMuted, setVideoMuted]);
 
  const [videoStream, audioInputs, videoInputs] = useAsyncMemo(async () => {
- let previewStream: MediaStream;
+ let devices = await MediaDeviceHandler.getDevices();
+
+ // We get the preview stream before requesting devices: this is because
+ // we need (in some browsers) an active media stream in order to get
+ // non-blank labels for the devices.
+ let stream: MediaStream | null = null;
  try {
- // We get the preview stream before requesting devices: this is because
- // we need (in some browsers) an active media stream in order to get
- // non-blank labels for the devices. According to the docs, we
- // need a stream of each type (audio + video) if we want to enumerate
- // audio & video devices, although this didn't seem to be the case
- // in practice for me. We request both anyway.
- // For similar reasons, we also request a stream even if video is muted,
- // which could be a bit strange but allows us to get the device list
- // reliably. One option could be to try & get devices without a stream,
- // then try again with a stream if we get blank deviceids, but... ew.
- previewStream = await navigator.mediaDevices.getUserMedia({
- video: { deviceId: videoInputId },
- audio: { deviceId: MediaDeviceHandler.getAudioInput() },
- });
+ if (devices.audioinput.length > 0) {
+ // Holding just an audio stream will be enough to get us all device labels, so
+ // if video is muted, don't bother requesting video.
+ stream = await navigator.mediaDevices.getUserMedia({
+ audio: true,
+ video: !videoMuted && devices.videoinput.length > 0 && { deviceId: videoInputId },
+ });
+ } else if (devices.videoinput.length > 0) {
+ // We have to resort to a video stream, even if video is supposed to be muted.
+ stream = await navigator.mediaDevices.getUserMedia({ video: { deviceId: videoInputId } });
+ }
  } catch (e) {
  logger.error(`Failed to get stream for device ${videoInputId}`, e);
  }
 
- const devices = await MediaDeviceHandler.getDevices();
+ // Refresh the devices now that we hold a stream
+ if (stream !== null) devices = await MediaDeviceHandler.getDevices();
 
- // If video is muted, we don't actually want the stream, so we can get rid of
- // it now.
+ // If video is muted, we don't actually want the stream, so we can get rid of it now.
  if (videoMuted) {
- previewStream.getTracks().forEach(t => t.stop());
- previewStream = undefined;
+ stream?.getTracks().forEach(t => t.stop());
+ stream = null;
  }
 
- return [previewStream, devices[MediaDeviceKindEnum.AudioInput], devices[MediaDeviceKindEnum.VideoInput]];
+ return [stream, devices.audioinput, devices.videoinput];
  }, [videoInputId, videoMuted], [null, [], []]);
 
  const setAudioInput = useCallback((device: MediaDeviceInfo) => {
@@ -188,7 +190,7 @@ export const Lobby: FC<LobbyProps> = ({ room, joinCallButtonDisabled, joinCallBu
  videoElement.play();
 
  return () => {
- videoStream?.getTracks().forEach(track => track.stop());
+ videoStream.getTracks().forEach(track => track.stop());
  videoElement.srcObject = null;
  };
  }
@@ -358,7 +360,7 @@ const JoinCallView: FC<JoinCallViewProps> = ({ room, resizing, call }) => {
  lobby = <Lobby
  room={room}
  connect={connect}
- joinCallButtonTooltip={joinCallButtonTooltip}
+ joinCallButtonTooltip={joinCallButtonTooltip ?? undefined}
  joinCallButtonDisabled={joinCallButtonDisabled}
  >
  { facePile }