shaka-player
Version:
DASH/EME video player library
246 lines (200 loc) • 6.5 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.metadata.VorbisUtils');
goog.require('shaka.metadata.Metadata');
goog.require('shaka.util.BufferUtils');
goog.require('shaka.util.DataViewReader');
goog.require('shaka.util.StringUtils');
// cspell:ignore ALBUMARTIST TRACKNUMBER DISCNUMBER
/**
* Metadata parser for Vorbis Comments (FLAC, OGG, Vorbis, Opus).
* @implements {shaka.extern.MetadataParser}
* @export
*/
shaka.metadata.VorbisUtils = class {
/**
* @override
* @export
*/
parse(data) {
const isFlac = data.length >= 4 &&
data[0] == 0x66 && // f
data[1] == 0x4C && // L
data[2] == 0x61 && // a
data[3] == 0x43; // C
if (isFlac) {
const frames = [];
let offset = 4;
while (offset + 4 <= data.length) {
const header = data[offset];
const isLast = !!(header & 0x80);
const blockType = header & 0x7F;
const length =
(data[offset + 1] << 16) |
(data[offset + 2] << 8) |
data[offset + 3];
offset += 4;
if (offset + length > data.length) {
break;
}
const block = data.subarray(offset, offset + length);
// VORBIS_COMMENT block
if (blockType == 4) {
frames.push(...this.parseVorbisCommentBlock_(block));
}
// PICTURE block
if (blockType == 6) {
const frame = this.parseFlacPicture_(block);
if (frame) {
frames.push(frame);
}
}
offset += length;
if (isLast) {
break;
}
}
return frames;
}
const isOgg = data.length >= 4 &&
data[0] == 0x4F && // O
data[1] == 0x67 && // g
data[2] == 0x67 && // g
data[3] == 0x53; // S
if (isOgg) {
const text = shaka.util.StringUtils.fromUTF8(data);
let index = text.indexOf('OpusTags');
if (index < 0) {
index = text.indexOf('vorbis');
}
if (index >= 0) {
return this.parseVorbisCommentBlock_(data.subarray(index + 8));
}
}
return [];
}
/**
* Parse Vorbis comment structure.
*
* @param {!Uint8Array} data
* @return {!Array<!shaka.extern.MetadataFrame>}
* @private
*/
parseVorbisCommentBlock_(data) {
const frames = [];
try {
const reader = new shaka.util.DataViewReader(
data, shaka.util.DataViewReader.Endianness.LITTLE_ENDIAN);
// vendor_length
const vendorLength = reader.readUint32();
reader.skip(vendorLength);
// user_comment_list_length
const commentCount = reader.readUint32();
for (let i = 0; i < commentCount; i++) {
const len = reader.readUint32();
const str = shaka.util.StringUtils.fromUTF8(
reader.readBytes(len, /* clone= */ false));
const eq = str.indexOf('=');
if (eq < 0) {
continue;
}
const vorbisKey = str.substring(0, eq).toUpperCase();
const value = str.substring(eq + 1);
const key =
shaka.metadata.VorbisUtils.VORBIS_TO_ID3_MAP_[vorbisKey] ||
vorbisKey;
frames.push({
key,
data: value,
description: '',
mimeType: null,
pictureType: null,
});
}
} catch (e) {
// Malformed Vorbis comment block.
}
return frames;
}
/**
* Parse a FLAC PICTURE metadata block (type 6) and return it as an
* APIC-equivalent MetadataFrame so that callers can treat album art from
* FLAC files the same way they treat ID3v2 APIC frames.
*
* FLAC PICTURE block layout (all fields big-endian):
* [0-3] picture type (uint32 BE)
* [4-7] MIME length (uint32 BE)
* [8 … 8+mimeLen-1] MIME type string (UTF-8)
* [8+mimeLen … +3] description length (uint32 BE)
* […+descLen-1] description string (UTF-8)
* [… + 4] width (uint32 BE) – ignored
* [… + 4] height (uint32 BE) – ignored
* [… + 4] color depth (uint32 BE) – ignored
* [… + 4] color count (uint32 BE) – ignored
* [… + 4] data length (uint32 BE)
* [… + dataLen] raw image bytes
*
* @param {!Uint8Array} block Raw bytes of the PICTURE metadata block body
* (i.e. the 4-byte block header has already been stripped).
* @return {?shaka.extern.MetadataFrame}
* @private
*/
parseFlacPicture_(block) {
const StringUtils = shaka.util.StringUtils;
try {
const reader = new shaka.util.DataViewReader(
block, shaka.util.DataViewReader.Endianness.BIG_ENDIAN);
const pictureType = reader.readUint32();
const mimeLength = reader.readUint32();
const mimeType = StringUtils.fromUTF8(
reader.readBytes(mimeLength, /* clone= */ true));
const descLength = reader.readUint32();
const description = StringUtils.fromUTF8(
reader.readBytes(descLength, /* clone= */ true));
// width, height, color depth, color count
reader.skip(16);
const dataLength = reader.readUint32();
const imageBytes = reader.readBytes(dataLength, /* clone= */ true);
return {
key: 'APIC',
data: shaka.util.BufferUtils.toArrayBuffer(imageBytes),
description,
mimeType,
pictureType,
};
} catch (e) {
return null;
}
}
};
/**
* @const {!Object<string, string>}
* @private
*/
shaka.metadata.VorbisUtils.VORBIS_TO_ID3_MAP_ = {
'TITLE': 'TIT2',
'ARTIST': 'TPE1',
'ALBUM': 'TALB',
'ALBUMARTIST': 'TPE2',
'TRACKNUMBER': 'TRCK',
'DISCNUMBER': 'TPOS',
'DATE': 'TDRC',
'GENRE': 'TCON',
'COMMENT': 'COMM',
'DESCRIPTION': 'TIT3',
'COPYRIGHT': 'TCOP',
'COMPOSER': 'TCOM',
'LYRICS': 'USLT',
'ISRC': 'TSRC',
};
shaka.metadata.Metadata.registerParserByMime(
'audio/flac', () => new shaka.metadata.VorbisUtils());
shaka.metadata.Metadata.registerParserByMime(
'audio/ogg', () => new shaka.metadata.VorbisUtils());
shaka.metadata.Metadata.registerParserByMime(
'audio/vorbis', () => new shaka.metadata.VorbisUtils());
shaka.metadata.Metadata.registerParserByMime(
'audio/opus', () => new shaka.metadata.VorbisUtils());