Reuse single PlaybackWorker between Playback instances (#12520)

* Terminate playback worker on destroy

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Reuse single PlaybackWorker between all Playbacks

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* ...

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/PlaybackEncoder.ts

@@ -0,0 +1,34 @@
+/*
+Copyright 2024 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// @ts-ignore - `.ts` is needed here to make TS happy
+import { Request, Response } from "./workers/playback.worker";
+import { WorkerManager } from "./WorkerManager";
+import playbackWorkerFactory from "./workers/playbackWorkerFactory";
+
+export class PlaybackEncoder {
+    private static internalInstance = new PlaybackEncoder();
+
+    public static get instance(): PlaybackEncoder {
+        return PlaybackEncoder.internalInstance;
+    }
+
+    private readonly worker = new WorkerManager<Request, Response>(playbackWorkerFactory());
+
+    public getPlaybackWaveform(input: Float32Array): Promise<number[]> {
+        return this.worker.call({ data: Array.from(input) }).then((resp) => resp.waveform);
+    }
+}