Add lyrics field to metadata

dev/convert.html

@@ -54,7 +54,8 @@
 				data: blobData,
 				kind: 'coverFront',
 				mimeType: 'image/jpeg'
-			}]
+			}],
+			lyrics: "There's no way\nThat it's not going there"
 		});
 
 		const conversion = await Mediabunny.Conversion.init({

src/metadata.ts

@@ -9,6 +9,7 @@ export type MediaMetadata = {
 	discNumber?: number;
 	genre?: string;
 	releasedAt?: Date;
+	lyrics?: string;
 	images?: {
 		data: Uint8Array;
 		mimeType: string;
@@ -47,6 +48,9 @@ export const validateMediaMetadata = (metadata: MediaMetadata) => {
 	if (metadata.releasedAt !== undefined && !(metadata.releasedAt instanceof Date)) {
 		throw new TypeError('metadata.releasedAt, when provided, must be a Date.');
 	}
+	if (metadata.lyrics !== undefined && typeof metadata.lyrics !== 'string') {
+		throw new TypeError('metadata.lyrics, when provided, must be a string.');
+	}
 	if (metadata.comment !== undefined && typeof metadata.comment !== 'string') {
 		throw new TypeError('metadata.comment, when provided, must be a string.');
 	}
@@ -72,14 +76,15 @@ export const validateMediaMetadata = (metadata: MediaMetadata) => {
 };
 
 export const mediaMetadataIsEmpty = (metadata: MediaMetadata) => {
-	return !metadata.title
+	return metadata.title === undefined
-		&& !metadata.artist
+		&& metadata.artist === undefined
-		&& !metadata.album
+		&& metadata.album === undefined
-		&& !metadata.albumArtist
+		&& metadata.albumArtist === undefined
-		&& !metadata.trackNumber
+		&& metadata.trackNumber === undefined
-		&& !metadata.discNumber
+		&& metadata.discNumber === undefined
-		&& !metadata.genre
+		&& metadata.genre === undefined
-		&& !metadata.releasedAt
+		&& metadata.releasedAt === undefined
-		&& !metadata.comment
+		&& metadata.lyrics === undefined
+		&& metadata.comment === undefined
 		&& (!metadata.images || metadata.images.length === 0);
 };

src/mp3/mp3-muxer.ts

@@ -130,38 +130,41 @@ export class Mp3Muxer extends Muxer {
 
 		const startPos = this.writer.getPos();
 
-		if (metadata.title) {
+		if (metadata.title !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TIT2', metadata.title);
 		}
-		if (metadata.artist) {
+		if (metadata.artist !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TPE1', metadata.artist);
 		}
-		if (metadata.album) {
+		if (metadata.album !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TALB', metadata.album);
 		}
-		if (metadata.albumArtist) {
+		if (metadata.albumArtist !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TPE2', metadata.albumArtist);
 		}
-		if (metadata.trackNumber) {
+		if (metadata.trackNumber !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TRCK', metadata.trackNumber.toString());
 		}
-		if (metadata.discNumber) {
+		if (metadata.discNumber !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TPOS', metadata.discNumber.toString());
 		}
-		if (metadata.genre) {
+		if (metadata.genre !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TCON', metadata.genre);
 		}
-		if (metadata.releasedAt) {
+		if (metadata.releasedAt !== undefined) {
 			this.mp3Writer.writeId3V2TextFrame('TDRC', metadata.releasedAt.toISOString().split('.')[0]!);
 		}
-		if (metadata.comment) {
+		if (metadata.lyrics !== undefined) {
+			this.mp3Writer.writeId3V2LyricsFrame(metadata.lyrics);
+		}
+		if (metadata.comment !== undefined) {
 			this.mp3Writer.writeId3V2CommentFrame(metadata.comment);
 		}
 		if (metadata.images) {
 			const pictureTypeMap = { coverFront: 0x03, coverBack: 0x04, unknown: 0x00 };
 			for (const image of metadata.images) {
 				const pictureType = pictureTypeMap[image.kind];
-				const description = image.description || '';
+				const description = image.description ?? '';
 				this.mp3Writer.writeId3V2ApicFrame(image.mimeType, pictureType, description, image.data);
 			}
 		}

src/mp3/mp3-reader.ts

@@ -350,6 +350,14 @@ export class Mp3Reader {
 					}
 				}; break;
 
+				case 'USLT':
+				case 'ULT': {
+					const encoding = reader.readU8();
+					reader.pos += 3; // Skip language
+					reader.readId3V2Text(encoding, frameEndPos); // Short content description
+					metadata.lyrics ??= reader.readId3V2Text(encoding, frameEndPos);
+				}; break;
+
 				case 'COMM':
 				case 'COM': {
 					const encoding = reader.readU8();

src/mp3/mp3-writer.ts

@@ -17,6 +17,7 @@ import {
 	SAMPLING_RATES,
 	XING,
 } from '../../shared/mp3-misc';
+import { Id3V2TextEncoding } from './mp3-reader';
 
 export type XingFrameData = {
 	mpegVersionId: number;
@@ -89,7 +90,7 @@ export class Mp3Writer {
 		this.writeSynchsafeU32(frameSize);
 		this.writeU16(0x0000);
 
-		this.writeU8(useIso88591 ? 0x00 : 0x03);
+		this.writeU8(useIso88591 ? Id3V2TextEncoding.ISO_8859_1 : Id3V2TextEncoding.UTF_8);
 		if (useIso88591) {
 			this.writeIsoString(text);
 		} else {
@@ -97,17 +98,38 @@ export class Mp3Writer {
 		}
 	}
 
+	writeId3V2LyricsFrame(lyrics: string) {
+		const useIso88591 = isIso88591Compatible(lyrics);
+		const shortDescription = '';
+		const frameSize = 1 + 3 + shortDescription.length + 1 + lyrics.length + 1;
+
+		this.writeAscii('USLT');
+		this.writeSynchsafeU32(frameSize);
+		this.writeU16(0x0000);
+
+		this.writeU8(useIso88591 ? Id3V2TextEncoding.ISO_8859_1 : Id3V2TextEncoding.UTF_8);
+		this.writeAscii('und');
+
+		if (useIso88591) {
+			this.writeIsoString(shortDescription);
+			this.writeIsoString(lyrics);
+		} else {
+			this.writeUtf8String(shortDescription);
+			this.writeUtf8String(lyrics);
+		}
+	}
+
 	writeId3V2CommentFrame(comment: string) {
 		const useIso88591 = isIso88591Compatible(comment);
 		const textDataLength = useIso88591 ? comment.length : textEncoder.encode(comment).byteLength;
-		const frameSize = 1 + 3 + 1 + textDataLength + 1;
 		const shortDescription = '';
+		const frameSize = 1 + 3 + shortDescription.length + 1 + textDataLength + 1;
 
 		this.writeAscii('COMM');
 		this.writeSynchsafeU32(frameSize);
 		this.writeU16(0x0000);
 
-		this.writeU8(useIso88591 ? 0x00 : 0x03);
+		this.writeU8(useIso88591 ? Id3V2TextEncoding.ISO_8859_1 : Id3V2TextEncoding.UTF_8);
 		this.writeU8(0x75); // 'u'
 		this.writeU8(0x6E); // 'n'
 		this.writeU8(0x64); // 'd'
@@ -130,7 +152,7 @@ export class Mp3Writer {
 		this.writeSynchsafeU32(frameSize);
 		this.writeU16(0x0000);
 
-		this.writeU8(useIso88591 ? 0x00 : 0x03);
+		this.writeU8(useIso88591 ? Id3V2TextEncoding.ISO_8859_1 : Id3V2TextEncoding.UTF_8);
 
 		if (useIso88591) {
 			this.writeIsoString(mimeType);