Cap recording length, and warn at 10s remaining

See diff for details. Note that this introduces an "Uploading" state which is not currently used.

At the moment, if a user hits the maximum time then their recording will be broken. This is expected to be fixed in a future PR.

src/components/views/rooms/MessageComposer.js

@@ -35,6 +35,8 @@ import ActiveWidgetStore from "../../../stores/ActiveWidgetStore";
 import {replaceableComponent} from "../../../utils/replaceableComponent";
 import VoiceRecordComposerTile from "./VoiceRecordComposerTile";
 import {VoiceRecordingStore} from "../../../stores/VoiceRecordingStore";
+import {RecordingState} from "../../../voice/VoiceRecording";
+import Tooltip, {Alignment} from "../elements/Tooltip";
 
 function ComposerAvatar(props) {
     const MemberStatusMessageAvatar = sdk.getComponent('avatars.MemberStatusMessageAvatar');
@@ -191,6 +193,7 @@ export default class MessageComposer extends React.Component {
             joinedConference: WidgetStore.instance.isJoinedToConferenceIn(this.props.room),
             isComposerEmpty: true,
             haveRecording: false,
+            recordingTimeLeftSeconds: null, // when set to a number, shows a toast
         };
     }
 
@@ -331,7 +334,17 @@ export default class MessageComposer extends React.Component {
     }
 
     _onVoiceStoreUpdate = () => {
-        this.setState({haveRecording: !!VoiceRecordingStore.instance.activeRecording});
+        const recording = VoiceRecordingStore.instance.activeRecording;
+        this.setState({haveRecording: !!recording});
+        if (recording) {
+            // We show a little head's up that the recording is about to automatically end soon. The 3s
+            // display time is completely arbitrary. Note that we don't need to deregister the listener
+            // because the recording instance will clean that up for us.
+            recording.on(RecordingState.EndingSoon, ({secondsLeft}) => {
+                this.setState({recordingTimeLeftSeconds: secondsLeft});
+                setTimeout(() => this.setState({recordingTimeLeftSeconds: null}), 3000);
+            });
+        }
     };
 
     render() {
@@ -412,8 +425,18 @@ export default class MessageComposer extends React.Component {
             );
         }
 
+        let recordingTooltip;
+        const secondsLeft = Math.round(this.state.recordingTimeLeftSeconds);
+        if (secondsLeft) {
+            recordingTooltip = <Tooltip
+                label={_t("%(seconds)ss left", {seconds: secondsLeft})}
+                alignment={Alignment.Top} yOffset={-50}
+            />;
+        }
+
         return (
             <div className="mx_MessageComposer mx_GroupLayout">
+                {recordingTooltip}
                 <div className="mx_MessageComposer_wrapper">
                     <ReplyPreview permalinkCreator={this.props.permalinkCreator} />
                     <div className="mx_MessageComposer_row">

src/i18n/strings/en_EN.json

@@ -1473,6 +1473,7 @@
     "The conversation continues here.": "The conversation continues here.",
     "This room has been replaced and is no longer active.": "This room has been replaced and is no longer active.",
     "You do not have permission to post to this room": "You do not have permission to post to this room",
+    "%(seconds)ss left": "%(seconds)ss left",
     "Bold": "Bold",
     "Italics": "Italics",
     "Strikethrough": "Strikethrough",

src/stores/VoiceRecordingStore.ts

@@ -73,9 +73,7 @@ export class VoiceRecordingStore extends AsyncStoreWithClient<IState> {
      */
     public disposeRecording(): Promise<void> {
         if (this.state.recording) {
-            // Stop for good measure, but completely async because we're not concerned with this
-            // passing or failing.
-            this.state.recording.stop().catch(e => console.error("Error stopping recording", e));
+            this.state.recording.destroy(); // stops internally
         }
         return this.updateState({recording: null});
     }

src/voice/VoiceRecording.ts

@@ -20,17 +20,29 @@ import {MatrixClient} from "matrix-js-sdk/src/client";
 import CallMediaHandler from "../CallMediaHandler";
 import {SimpleObservable} from "matrix-widget-api";
 import {clamp} from "../utils/numbers";
+import EventEmitter from "events";
+import {IDestroyable} from "../utils/IDestroyable";
 
 const CHANNELS = 1; // stereo isn't important
 const SAMPLE_RATE = 48000; // 48khz is what WebRTC uses. 12khz is where we lose quality.
 const BITRATE = 24000; // 24kbps is pretty high quality for our use case in opus.
+const TARGET_MAX_LENGTH = 120; // 2 minutes in seconds. Somewhat arbitrary, though longer == larger files.
+const TARGET_WARN_TIME_LEFT = 10; // 10 seconds, also somewhat arbitrary.
 
 export interface IRecordingUpdate {
     waveform: number[]; // floating points between 0 (low) and 1 (high).
     timeSeconds: number; // float
 }
 
-export class VoiceRecording {
+export enum RecordingState {
+    Started = "started",
+    EndingSoon = "ending_soon", // emits an object with a single numerical value: secondsLeft
+    Ended = "ended",
+    Uploading = "uploading",
+    Uploaded = "uploaded",
+}
+
+export class VoiceRecording extends EventEmitter implements IDestroyable {
     private recorder: Recorder;
     private recorderContext: AudioContext;
     private recorderSource: MediaStreamAudioSourceNode;
@@ -40,9 +52,12 @@ export class VoiceRecording {
     private buffer = new Uint8Array(0);
     private mxc: string;
     private recording = false;
+    private stopping = false;
+    private haveWarned = false; // whether or not EndingSoon has been fired
     private observable: SimpleObservable<IRecordingUpdate>;
 
     public constructor(private client: MatrixClient) {
+        super();
     }
 
     private async makeRecorder() {
@@ -124,7 +139,7 @@ export class VoiceRecording {
         return this.mxc;
     }
 
-    private tryUpdateLiveData = (ev: AudioProcessingEvent) => {
+    private processAudioUpdate = (ev: AudioProcessingEvent) => {
         if (!this.recording) return;
 
         // The time domain is the input to the FFT, which means we use an array of the same
@@ -150,6 +165,17 @@ export class VoiceRecording {
             waveform: translatedData,
             timeSeconds: ev.playbackTime,
         });
+
+        // Now that we've updated the data/waveform, let's do a time check. We don't want to
+        // go horribly over the limit. We also emit a warning state if needed.
+        const secondsLeft = TARGET_MAX_LENGTH - ev.playbackTime;
+        if (secondsLeft <= 0) {
+            // noinspection JSIgnoredPromiseFromCall - we aren't concerned with it overlapping
+            this.stop();
+        } else if (secondsLeft <= TARGET_WARN_TIME_LEFT && !this.haveWarned) {
+            this.emit(RecordingState.EndingSoon, {secondsLeft});
+            this.haveWarned = true;
+        }
     };
 
     public async start(): Promise<void> {
@@ -164,9 +190,10 @@ export class VoiceRecording {
         }
         this.observable = new SimpleObservable<IRecordingUpdate>();
         await this.makeRecorder();
-        this.recorderProcessor.addEventListener("audioprocess", this.tryUpdateLiveData);
+        this.recorderProcessor.addEventListener("audioprocess", this.processAudioUpdate);
         await this.recorder.start();
         this.recording = true;
+        this.emit(RecordingState.Started);
     }
 
     public async stop(): Promise<Uint8Array> {
@@ -174,6 +201,9 @@ export class VoiceRecording {
             throw new Error("No recording to stop");
         }
 
+        if (this.stopping) return;
+        this.stopping = true;
+
         // Disconnect the source early to start shutting down resources
         this.recorderSource.disconnect();
         await this.recorder.stop();
@@ -187,12 +217,19 @@ export class VoiceRecording {
 
         // Finally do our post-processing and clean up
         this.recording = false;
-        this.recorderProcessor.removeEventListener("audioprocess", this.tryUpdateLiveData);
+        this.recorderProcessor.removeEventListener("audioprocess", this.processAudioUpdate);
         await this.recorder.close();
+        this.emit(RecordingState.Ended);
 
         return this.buffer;
     }
 
+    public destroy() {
+        // noinspection JSIgnoredPromiseFromCall - not concerned about stop() being called async here
+        this.stop();
+        this.removeAllListeners();
+    }
+
     public async upload(): Promise<string> {
         if (!this.hasRecording) {
             throw new Error("No recording available to upload");
@@ -200,11 +237,13 @@ export class VoiceRecording {
 
         if (this.mxc) return this.mxc;
 
+        this.emit(RecordingState.Uploading);
         this.mxc = await this.client.uploadContent(new Blob([this.buffer], {
             type: "audio/ogg",
         }), {
             onlyContentUri: false, // to stop the warnings in the console
         }).then(r => r['content_uri']);
+        this.emit(RecordingState.Uploaded);
         return this.mxc;
     }
 }