95 lines
2.6 KiB
JavaScript
95 lines
2.6 KiB
JavaScript
import { ERROR_TERMINATED } from "./ffmpeg/package/dist/esm/errors.js";
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export class VideoCompressor {
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constructor(progressBar) {
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this.progressBar = progressBar;
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this.ffmpeg = new FFmpegWASM.FFmpeg();
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this.inProgress = false;
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}
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async compress(file, filesizeBytes, duration) {
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this.progressBar.setStatus("Initializing...");
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this.inProgress = true;
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const progressCallback = event => this.progressBar.setProgress(event.progress);
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this.ffmpeg.on("progress", progressCallback);
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const filesizeKbit = filesizeBytes * 0.008;
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// Calculate target bitrate to create a video file with desired file size (https://trac.ffmpeg.org/wiki/Encode/H.264#twopass)
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let bitrate = filesizeKbit / duration;
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bitrate -= 128; // Subtract audio bitrate
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bitrate -= (bitrate / 100) * 5; // Subtract 5% to compensate for overhead
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bitrate = Math.floor(bitrate);
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if (bitrate <= 0) {
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this.inProgress = false;
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throw new Error("Selected file size is too low for this video");
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}
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console.debug("Target bitrate:", bitrate, "Video length:", duration);
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// Run compression
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try {
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await this.ffmpeg.load({ coreURL: "/assets/scripts/core/package/dist/umd/ffmpeg-core.js" });
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await this.ffmpeg.writeFile(file.name, await this.readFromBlob(file));
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await this.ffmpeg.exec(["-i", file.name, "-preset", "ultrafast", "-c:v", "libx264", "-b:v", bitrate + "k", "-c:a", "copy", "-b:a", "128k", "compressed.mp4"]);
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} catch (e) {
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// Ignore termination error
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if (e.message === ERROR_TERMINATED.message) {
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this.inProgress = false;
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return null;
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}
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throw e;
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}
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const video = await this.ffmpeg.readFile("compressed.mp4");
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const resultFile = new File([video.buffer], this.generateFileName(file.name), { type: "video/mp4" });
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// Clean up
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this.ffmpeg.off("progress", progressCallback);
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this.inProgress = false;
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return resultFile;
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}
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stop() {
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this.ffmpeg.terminate();
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this.inProgress = false;
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}
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generateFileName(filename) {
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let name = filename.replace(/\.\w+$/, "");
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if (/\s/.test(name)) name += " compressed";
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else name += "_compressed";
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return name + ".mp4";
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}
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// https://github.com/ffmpegwasm/ffmpeg.wasm/blob/main/packages/util/src/index.ts
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readFromBlob(blob) {
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return new Promise((resolve, reject) => {
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const fileReader = new FileReader();
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fileReader.onload = () => {
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const { result } = fileReader;
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if (result instanceof ArrayBuffer) {
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resolve(new Uint8Array(result));
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} else {
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resolve(new Uint8Array());
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}
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};
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fileReader.onerror = (event) => {
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reject(Error(`File could not be read! Code=${event?.target?.error?.code || -1}`));
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};
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fileReader.readAsArrayBuffer(blob);
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});
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}
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}
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