Start work on demuxing

src/input-track.ts

@@ -0,0 +1,121 @@
+import { AudioCodec, MediaCodec, VideoCodec } from './codec';
+
+export interface InputTrackBacking {
+	getCodec(): Promise<MediaCodec>;
+	getDuration(): Promise<number>;
+}
+
+export abstract class InputTrack {
+	/** @internal */
+	_backing: InputTrackBacking;
+
+	/** @internal */
+	constructor(backing: InputTrackBacking) {
+		this._backing = backing;
+	}
+
+	abstract getCodec(): Promise<MediaCodec>;
+	abstract getCodecMimeType(): Promise<string>;
+
+	isVideoTrack(): this is InputVideoTrack {
+		return this instanceof InputVideoTrack;
+	}
+
+	isAudioTrack(): this is InputAudioTrack {
+		return this instanceof InputAudioTrack;
+	}
+
+	getDuration() {
+		return this._backing.getDuration();
+	}
+}
+
+export interface InputVideoTrackBacking extends InputTrackBacking {
+	getCodec(): Promise<VideoCodec>;
+	getWidth(): Promise<number>;
+	getHeight(): Promise<number>;
+	getRotation(): Promise<number>;
+	getDecoderConfig(): Promise<VideoDecoderConfig>;
+	getFirstChunk(): Promise<EncodedVideoChunk | null>;
+	getChunk(timestamp: number): Promise<EncodedVideoChunk | null>;
+	getNextChunk(chunk: EncodedVideoChunk): Promise<EncodedVideoChunk | null>;
+	getKeyChunk(timestamp: number): Promise<EncodedVideoChunk | null>;
+	getNextKeyChunk(chunk: EncodedVideoChunk): Promise<EncodedVideoChunk | null>;
+}
+
+export class InputVideoTrack extends InputTrack {
+	/** @internal */
+	override _backing: InputVideoTrackBacking;
+
+	/** @internal */
+	constructor(backing: InputVideoTrackBacking) {
+		super(backing);
+
+		this._backing = backing;
+	}
+
+	getCodec() {
+		return this._backing.getCodec();
+	}
+
+	getWidth() {
+		return this._backing.getWidth();
+	}
+
+	getHeight() {
+		return this._backing.getHeight();
+	}
+
+	getRotation() {
+		return this._backing.getRotation();
+	}
+
+	getDecoderConfig() {
+		return this._backing.getDecoderConfig();
+	}
+
+	async getCodecMimeType() {
+		const decoderConfig = await this.getDecoderConfig();
+		return decoderConfig.codec;
+	}
+}
+
+export interface InputAudioTrackBacking extends InputTrackBacking {
+	getCodec(): Promise<AudioCodec>;
+	getNumberOfChannels(): Promise<number>;
+	getSampleRate(): Promise<number>;
+	getDecoderConfig(): Promise<AudioDecoderConfig>;
+}
+
+export class InputAudioTrack extends InputTrack {
+	/** @internal */
+	override _backing: InputAudioTrackBacking;
+
+	/** @internal */
+	constructor(backing: InputAudioTrackBacking) {
+		super(backing);
+
+		this._backing = backing;
+	}
+
+	getCodec() {
+		return this._backing.getCodec();
+	}
+
+	getNumberOfChannels() {
+		return this._backing.getNumberOfChannels();
+	}
+
+	getSampleRate() {
+		return this._backing.getSampleRate();
+	}
+
+	getDecoderConfig() {
+		return this._backing.getDecoderConfig();
+	}
+
+	async getCodecMimeType() {
+		const decoderConfig = await this.getDecoderConfig();
+		return decoderConfig.codec;
+	}
+}