Add Matroska muxer

src/matroska/ebml.ts

@@ -0,0 +1,122 @@
+export interface EBMLElement {
+	id: number,
+	size?: number,
+	data: number | string | Uint8Array | EBMLFloat32 | EBMLFloat64 | (EBML | null)[]
+}
+
+export type EBML = EBMLElement | Uint8Array | (EBML | null)[];
+
+/** Wrapper around a number to be able to differentiate it in the writer. */
+export class EBMLFloat32 {
+	value: number;
+
+	constructor(value: number) {
+		this.value = value;
+	}
+}
+
+/** Wrapper around a number to be able to differentiate it in the writer. */
+export class EBMLFloat64 {
+	value: number;
+
+	constructor(value: number) {
+		this.value = value;
+	}
+}
+
+/** Defines some of the EBML IDs used by Matroska files. */
+export enum EBMLId {
+	EBML = 0x1a45dfa3,
+	EBMLVersion = 0x4286,
+	EBMLReadVersion = 0x42f7,
+	EBMLMaxIDLength = 0x42f2,
+	EBMLMaxSizeLength = 0x42f3,
+	DocType = 0x4282,
+	DocTypeVersion = 0x4287,
+	DocTypeReadVersion = 0x4285,
+	SeekHead = 0x114d9b74,
+	Seek = 0x4dbb,
+	SeekID = 0x53ab,
+	SeekPosition = 0x53ac,
+	Duration = 0x4489,
+	Info = 0x1549a966,
+	TimestampScale = 0x2ad7b1,
+	MuxingApp = 0x4d80,
+	WritingApp = 0x5741,
+	Tracks = 0x1654ae6b,
+	TrackEntry = 0xae,
+	TrackNumber = 0xd7,
+	TrackUID = 0x73c5,
+	TrackType = 0x83,
+	CodecID = 0x86,
+	CodecPrivate = 0x63a2,
+	DefaultDuration = 0x23e383,
+	Video = 0xe0,
+	PixelWidth = 0xb0,
+	PixelHeight = 0xba,
+	Void = 0xec,
+	Audio = 0xe1,
+	SamplingFrequency = 0xb5,
+	Channels = 0x9f,
+	BitDepth = 0x6264,
+	Segment = 0x18538067,
+	SimpleBlock = 0xa3,
+	BlockGroup = 0xa0,
+	Block = 0xa1,
+	BlockAdditions = 0x75a1,
+	BlockDuration = 0x9b,
+	ReferenceBlock = 0xfb,
+	Cluster = 0x1f43b675,
+	Timestamp = 0xe7,
+	Cues = 0x1c53bb6b,
+	CuePoint = 0xbb,
+	CueTime = 0xb3,
+	CueTrackPositions = 0xb7,
+	CueTrack = 0xf7,
+	CueClusterPosition = 0xf1,
+	Colour = 0x55b0,
+	MatrixCoefficients = 0x55b1,
+	TransferCharacteristics = 0x55ba,
+	Primaries = 0x55bb,
+	Range = 0x55b9,
+	AlphaMode = 0x53c0
+}
+
+export const measureUnsignedInt = (value: number) => {
+	// Force to 32-bit unsigned integer
+	if (value < (1 << 8)) {
+		return 1;
+	} else if (value < (1 << 16)) {
+		return 2;
+	} else if (value < (1 << 24)) {
+		return 3;
+	} else if (value < 2**32) {
+		return 4;
+	} else if (value < 2**40) {
+		return 5;
+	} else {
+		return 6;
+	}
+};
+
+export const measureEBMLVarInt = (value: number) => {
+	if (value < (1 << 7) - 1) {
+		/** Top bit is set, leaving 7 bits to hold the integer, but we can't store
+		 * 127 because "all bits set to one" is a reserved value. Same thing for the
+		 * other cases below:
+		 */
+		return 1;
+	} else if (value < (1 << 14) - 1) {
+		return 2;
+	} else if (value < (1 << 21) - 1) {
+		return 3;
+	} else if (value < (1 << 28) - 1) {
+		return 4;
+	} else if (value < 2**35-1) {
+		return 5;
+	} else if (value < 2**42-1) {
+		return 6;
+	} else {
+		throw new Error('EBML VINT size not supported ' + value);
+	}
+};