checkpoint

find-loudness.ts

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+import { createReadStream } from "fs";
+
+export type SwapPoint = {
+	position_start: number;
+	duration: number;
+	loud: boolean;
+	label: string;
+};
+
+export default async function (
+	file: import("fs").PathLike,
+	threshold_at_point: number,
+	inertia_samples: number,
+	label: string
+): Promise<SwapPoint[]> {
+	const stream = createReadStream(file);
+	let position = 0;
+	const results: SwapPoint[] = [];
+	let last_swap_position = 0;
+	let keep_loud_until = 0;
+	let was_loud_last_time = false;
+	return new Promise((resolve, reject) => {
+		stream.on("readable", () => {
+			let chunk: Buffer | null;
+			while ((chunk = stream.read()) !== null) {
+				for (let i = 0; i < chunk.byteLength; i++) {
+					position++;
+					const byte = chunk[i];
+					const volume = Math.abs(byte - 128);
+					if (position >= keep_loud_until) {
+						const is_loud: boolean = volume > threshold_at_point;
+						if (is_loud != was_loud_last_time) {
+							const swap_point = {
+								position_start: last_swap_position,
+								duration: position - last_swap_position,
+								loud: was_loud_last_time,
+								label,
+							};
+							results.push(swap_point);
+							last_swap_position = position;
+							was_loud_last_time = is_loud;
+						}
+					}
+					if (volume > threshold_at_point) {
+						keep_loud_until = position + inertia_samples;
+					}
+				}
+			}
+		});
+		stream.on("end", () => {
+			resolve(results);
+		});
+
+		stream.on("error", reject);
+	});
+}

generate.sh

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+#!/bin/bash
+
+#
+#  Musisz mieć globalnie zainstalowane ts-node (npm install -g ts-node)
+#
+#  W katalogu z tym skryptem musisz mieć katalog "pics", w którym są pliki "left.png", "right.png", "none.png" i "both.png"
+#
+
+input=/home/kuba/Downloads/podcast-01-after-effects.mp3  # tutaj dajemy ścieżkę do pliku mp3 z Arkiem w jednym kanale i Kubą w drugim
+
+aresample=8000   # to bez zmian
+
+echo dzielimy mp3 na dwa osobne wav
+ffmpeg -i $input -map_channel 0.0.0 /tmp/left.wav -map_channel 0.0.1 /tmp/right.wav
+
+echo na dwóch wątkach generujemy surowe pliki
+ffmpeg -i /tmp/left.wav -ac 1 -filter:a aresample=$aresample -map 0:a -c:a pcm_u8 -f data -  > /tmp/leftraw &
+ffmpeg -i /tmp/right.wav -ac 1 -filter:a aresample=$aresample -map 0:a -c:a pcm_u8 -f data -  > /tmp/rightraw &
+
+# czekamy aż obydwa wątki się zakończą
+wait;
+
+echo "generating the demuxers...";
+
+# generuje ścieżki do złożenia przez ffmpega:
+ts-node generate-demuxer.ts  > /tmp/demuxer.txt
+
+mkdir -f out
+
+# używa demuxer.txt żeby skleić końcowe video z dźwiękiem:
+echo generowanie całości
+ffmpeg -y -f concat -i /tmp/demuxer.txt -r 30 -tune stillimage -vsync vfr -pix_fmt yuv420p out/video.mp4
+
+echo łączenie video z dźwiękiem:
+ffmpeg  -i video.mp4 -i $input -ac 1 -tune stillimage out/video-and-audio.mp4

window.ts

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+export default class Window {
+	length: number;
+	buffer: number[] = [];
+	constructor(length: number) {
+		this.length = length;
+	}
+
+	push(element: number) {
+		if (this.buffer.length == this.length) {
+			this.buffer.shift();
+		}
+		this.buffer.push(element);
+	}
+
+	sum() {
+		return this.buffer.reduce((a, b) => a + b, 0);
+	}
+
+	clear() {
+		this.buffer = [];
+	}
+
+	isFull() {
+		return this.buffer.length == this.length;
+	}
+}