Add support for SYLT frame

v2/common_ids.go

@@ -54,6 +54,7 @@ var (
 		"User defined text information frame":      "TXXX",
 		"Unique file identifier":                   "UFID",
 		"Unsynchronised lyrics/text transcription": "USLT",
+		"Synchronised lyrics/text":                 "SYLT",
 
 		// Just for convenience.
 		"Artist": "TPE1",
@@ -114,6 +115,7 @@ var (
 		"User defined text information frame":      "TXXX",
 		"Unique file identifier":                   "UFID",
 		"Unsynchronised lyrics/text transcription": "USLT",
+		"Synchronised lyrics/text":                 "SYLT",
 
 		// Deprecated frames of ID3v2.3.
 		"Date":                  "TDRC",
@@ -145,6 +147,7 @@ var parsers = map[string]func(*bufReader, byte) (Framer, error){
 	"TXXX": parseUserDefinedTextFrame,
 	"UFID": parseUFIDFrame,
 	"USLT": parseUnsynchronisedLyricsFrame,
+	"SYLT": parseSynchronisedLyricsFrame,
 }
 
 // mustFrameBeInSequence checks if frame with corresponding ID must

v2/synchronised_lyrics_frame.go

@@ -0,0 +1,130 @@
+// Copyright 2016 Albert Nigmatzianov. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package id3v2
+
+import (
+	"encoding/binary"
+	"io"
+)
+
+// SynchronisedLyricsFrame is used to work with SYLT frames.
+// The information about how to add synchronised lyrics/text frame to tag
+// you can see in the docs to tag.AddSynchronisedLyricsFrame function.
+//
+// You must choose a three-letter language code from
+// ISO 639-2 code list: https://www.loc.gov/standards/iso639-2/php/code_list.php
+type SynchronisedLyricsFrame struct {
+	Encoding          Encoding
+	Language          string
+	TimestampFormat   byte
+	ContentType       byte
+	ContentDescriptor string
+	SynchronizedTexts []SyncedText
+}
+
+type TimestampFormat int
+
+const (
+	Unknown                               byte = iota
+	SYLTAbsoluteMpegFramesTimestampFormat      = iota + 1
+	SYLTAbsoluteMillisecondsTimestampFormat
+
+	SYLTOtherContentType = iota
+	SYLTLyricsContentType
+	SYLTTextTranscriptionContentType
+	SYLTMovementContentType
+	SYLTEventsContentType
+	SYLTChordContentType
+	SYLTTriviaContentType
+	SYLTWebpageURLsContentType
+	SYLTImageURLsContentType
+)
+
+type SyncedText struct {
+	Text      string
+	Timestamp uint32
+}
+
+func (sylf SynchronisedLyricsFrame) Size() int {
+	var s int
+	for _, v := range sylf.SynchronizedTexts {
+		s += encodedSize(v.Text, sylf.Encoding)
+		s += len(sylf.Encoding.TerminationBytes)
+		s += 4
+	}
+
+	return 1 + len(sylf.Language) + encodedSize(sylf.ContentDescriptor, sylf.Encoding) +
+		+len(sylf.Encoding.TerminationBytes) + s +
+		+1 + 1
+}
+
+func (sylf SynchronisedLyricsFrame) UniqueIdentifier() string {
+	return sylf.Language + sylf.ContentDescriptor
+}
+
+func (sy SyncedText) uintToBytes() []byte {
+	bs := make([]byte, 4)
+	binary.BigEndian.PutUint32(bs, sy.Timestamp)
+	return bs
+}
+
+func bytesToInt(timeStampBytes []byte) uint32 {
+	return binary.BigEndian.Uint32(timeStampBytes)
+}
+
+func (sylf SynchronisedLyricsFrame) WriteTo(w io.Writer) (n int64, err error) {
+	if len(sylf.Language) != 3 {
+		return n, ErrInvalidLanguageLength
+	}
+	return useBufWriter(w, func(bw *bufWriter) {
+		bw.WriteByte(sylf.Encoding.Key)
+		bw.WriteString(sylf.Language)
+		bw.WriteByte(sylf.TimestampFormat)
+		bw.WriteByte(sylf.ContentType)
+		bw.EncodeAndWriteText(sylf.ContentDescriptor, sylf.Encoding)
+		bw.Write(sylf.Encoding.TerminationBytes)
+		for _, v := range sylf.SynchronizedTexts {
+			bw.EncodeAndWriteText(v.Text, sylf.Encoding)
+			bw.Write(sylf.Encoding.TerminationBytes)
+			bw.Write(v.uintToBytes())
+		}
+	})
+}
+
+func parseSynchronisedLyricsFrame(br *bufReader, version byte) (Framer, error) {
+	encoding := getEncoding(br.ReadByte())
+	language := br.Next(3)
+	timestampFormat := br.ReadByte()
+	contentType := br.ReadByte()
+	contentDescriptor := br.ReadText(encoding)
+
+	if br.Err() != nil {
+		return nil, br.Err()
+	}
+
+	var s []SyncedText
+	for {
+		textLyric, err := br.readTillDelims(encoding.TerminationBytes)
+		if err != nil {
+			break
+		}
+		t := SyncedText{Text: decodeText(textLyric, encoding)}
+		br.Next(len(encoding.TerminationBytes))
+		timeStamp := br.Next(4)
+		timeStampUint := bytesToInt(timeStamp)
+		t.Timestamp = timeStampUint
+		s = append(s, t)
+	}
+	sylf := SynchronisedLyricsFrame{
+		Encoding:          encoding,
+		Language:          string(language),
+		TimestampFormat:   timestampFormat,
+		ContentType:       contentType,
+		ContentDescriptor: decodeText(contentDescriptor, encoding),
+		SynchronizedTexts: s,
+	}
+
+	return sylf, nil
+}

v2/tag.go

@@ -73,6 +73,12 @@ func (tag *Tag) AddUnsynchronisedLyricsFrame(uslf UnsynchronisedLyricsFrame) {
 	tag.AddFrame(tag.CommonID("Unsynchronised lyrics/text transcription"), uslf)
 }
 
+// AddSynchronisedLyricsFrame adds the unsynchronised lyrics/text frame
+// to tag.
+func (tag *Tag) AddSynchronisedLyricsFrame(sylf SynchronisedLyricsFrame) {
+	tag.AddFrame(tag.CommonID("Synchronised lyrics/text"), sylf)
+}
+
 // AddUserDefinedTextFrame adds the custom frame (TXXX) to tag.
 func (tag *Tag) AddUserDefinedTextFrame(udtf UserDefinedTextFrame) {
 	tag.AddFrame(tag.CommonID("User defined text information frame"), udtf)