webrtc: add advanced audio settings

autoGainControl, echoCancellation, and noiseSuppression are audio
processing options that are usually enabled by default on WebRTC input
tracks.

This commit adds the possibility to enable/disable them, as they can be
undesirable in some cases (audiophile use cases). For example, one might
want to stream electronic dance music, which is basically noise, so it
should not be suppressed in that specific case.

Note that these are not exact settings, they are set as "ideal" in order
not to break anything on devices where those constraints are not
implemented.

Signed-off-by: László Várady <[email protected]>

src/webrtc/mediaHandler.ts

@@ -21,8 +21,15 @@ import { logger } from "../logger";
 import { MatrixClient } from "../client";
 import { CallState } from "./call";
 
+export interface AudioSettings {
+    autoGainControl: boolean;
+    echoCancellation: boolean;
+    noiseSuppression: boolean;
+}
+
 export class MediaHandler {
     private audioInput?: string;
+    private audioSettings?: AudioSettings;
     private videoInput?: string;
     private localUserMediaStream?: MediaStream;
     public userMediaStreams: MediaStream[] = [];
@@ -44,6 +51,17 @@ export class MediaHandler {
         await this.updateLocalUsermediaStreams();
     }
 
+    /**
+     * Set audio settings for MatrixCalls
+     * @param {AudioSettings} opts audio options to set
+     */
+    public async setAudioSettings(opts: AudioSettings): Promise<void> {
+        logger.info("LOG setting audio settings to", opts);
+
+        this.audioSettings = Object.assign({}, opts) as AudioSettings;
+        await this.updateLocalUsermediaStreams();
+    }
+
     /**
      * Set a video input device to use for MatrixCalls
      * @param {string} deviceId the identifier for the device
@@ -256,6 +274,9 @@ export class MediaHandler {
             audio: audio
                 ? {
                     deviceId: this.audioInput ? { ideal: this.audioInput } : undefined,
+                    autoGainControl: this.audioSettings ? { ideal: this.audioSettings.autoGainControl } : undefined,
+                    echoCancellation: this.audioSettings ? { ideal: this.audioSettings.echoCancellation } : undefined,
+                    noiseSuppression: this.audioSettings ? { ideal: this.audioSettings.noiseSuppression } : undefined,
                 }
                 : false,
             video: video