Add api-extractor and add required exports

src/output-format.ts

@@ -0,0 +1,55 @@
+import { IsobmffMuxer } from "./isobmff/isobmff-muxer";
+import { MatroskaMuxer } from "./matroska/matroska-muxer";
+import { Muxer } from "./muxer";
+import { Output } from "./output";
+
+/** @public */
+export abstract class OutputFormat {
+	/** @internal */
+	abstract _createMuxer(output: Output): Muxer;
+}
+
+/** @public */
+export class Mp4OutputFormat extends OutputFormat {
+	constructor(public options: {
+		fastStart?: false | 'in-memory' | 'fragmented',
+	} = {}) {
+		if (!options || typeof options !== 'object') {
+			throw new TypeError('options must be an object.');
+		}
+		if (options.fastStart !== undefined && ![false, 'in-memory', 'fragmented'].includes(options.fastStart)) {
+			throw new TypeError('options.fastStart, when provided, must be false, "in-memory", or "fragmented".');
+		}
+
+		super();
+	}
+
+	/** @internal */
+	override _createMuxer(output: Output) {
+		return new IsobmffMuxer(output, this);
+	}
+}
+
+/** @public */
+export class MkvOutputFormat extends OutputFormat {
+	constructor(public options: {
+		streamable?: boolean
+	} = {}) {
+		if (!options || typeof options !== 'object') {
+			throw new TypeError('options must be an object.');
+		}
+		if (options.streamable !== undefined && typeof options.streamable !== 'boolean') {
+			throw new TypeError('options.streamable, when provided, must be a boolean.');
+		}
+
+		super();
+	}
+
+	/** @internal */
+	override _createMuxer(output: Output) {
+		return new MatroskaMuxer(output, this);
+	}
+}
+
+/** @public */
+export class WebMOutputFormat extends MkvOutputFormat {}