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35 lines
1.1 KiB
TypeScript
35 lines
1.1 KiB
TypeScript
/*
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Copyright 2024 New Vector Ltd.
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Copyright 2022 The Matrix.org Foundation C.I.C.
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SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
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Please see LICENSE files in the repository root for full details.
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*/
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import { WorkerPayload } from "./worker";
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import { arrayRescale, arraySmoothingResample } from "../utils/arrays";
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import { PLAYBACK_WAVEFORM_SAMPLES } from "../audio/consts";
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const ctx: Worker = self as any;
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export interface Request {
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data: number[];
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}
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export interface Response {
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waveform: number[];
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}
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ctx.addEventListener("message", async (event: MessageEvent<Request & WorkerPayload>): Promise<void> => {
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const { seq, data } = event.data;
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// First, convert negative amplitudes to positive so we don't detect zero as "noisy".
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const noiseWaveform = data.map((v) => Math.abs(v));
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// Then, we'll resample the waveform using a smoothing approach so we can keep the same rough shape.
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// We also rescale the waveform to be 0-1 so we end up with a clamped waveform to rely upon.
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const waveform = arrayRescale(arraySmoothingResample(noiseWaveform, PLAYBACK_WAVEFORM_SAMPLES), 0, 1);
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ctx.postMessage({ seq, waveform });
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});
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