Start implementation

src/output.ts

@@ -0,0 +1,84 @@
+import { Muxer } from "./muxer";
+import { OutputFormat } from "./output_format";
+import { AudioSource, VideoSource } from "./source";
+import { Target } from "./target";
+import { Writer } from "./writer";
+
+type OutputOptions = {
+	format: OutputFormat,
+	target: Target
+};
+
+export type OutputTrack = {
+	id: number,
+	output: Output
+} & ({
+	type: 'video',
+	source: VideoSource
+} | {
+	type: 'audio',
+	source: AudioSource
+});
+
+export type OutputVideoTrack = OutputTrack & { type: 'video' };
+export type OutputAudioTrack = OutputTrack & { type: 'audio' };
+
+export class Output {
+	muxer: Muxer;
+	writer: Writer;
+	tracks: OutputTrack[] = [];
+	started = false;
+	finalizing = false;
+
+	constructor(options: OutputOptions) {
+		this.writer = options.target.createWriter();
+		this.muxer = options.format.createMuxer(this);
+	}
+
+	addTrack(source: VideoSource | AudioSource) {
+		if (this.started) {
+			throw new Error('Cannot add track after output has started.');
+		}
+		if (source.connectedTrack) {
+			throw new Error('Source is already used for a track.');
+		}
+
+		const track = {
+			id: this.tracks.length + 1,
+			output: this,
+			type: source instanceof VideoSource ? 'video' : 'audio',
+			source
+		} as OutputTrack;
+
+		this.tracks.push(track);
+		source.connectedTrack = track;
+	}
+
+	start() {
+		if (this.started) {
+			throw new Error('Output already started.');
+		}
+
+		this.started = true;
+		this.muxer.start();
+
+		for (const track of this.tracks) {
+			track.source.start();
+		}
+	}
+
+	async finalize() {
+		if (this.finalizing) {
+			throw new Error('Cannot call finalize twice.');
+		}
+		this.finalizing = true;
+
+		const promises = this.tracks.map(x => x.source.flush());
+		await Promise.all(promises);
+
+		this.muxer.finalize();
+
+		this.writer.flush();
+		this.writer.finalize();
+	}
+}