Be a little less strict on invalid frames

Add iTunes frames and ignore unknown frame instead of bypassing all remaining
frames

id3v2.go

@@ -219,11 +219,6 @@ func readID3v2Frames(r io.Reader, h *id3v2Header) (map[string]interface{}, error
 			return nil, err
 		}
 
-		// Avoid corrupted padding (see http://id3.org/Compliance%20Issues).
-		if !validID3Frame(h.Version, name) {
-			break
-		}
-
 		// FIXME: Do we still need this?
 		// if size=0, we certainly are in a padding zone. ignore the rest of
 		// the tags
@@ -233,6 +228,20 @@ func readID3v2Frames(r io.Reader, h *id3v2Header) (map[string]interface{}, error
 
 		offset += headerSize + size
 
+		// Avoid corrupted padding (see http://id3.org/Compliance%20Issues).
+		if !validID3Frame(h.Version, name) {
+			// There is a real problem with this frame
+			if offset > h.Size {
+				break
+			}
+
+			// just ignore this frame, maybe it's just a proprietary one
+			if _, err = readBytes(r, size); err != nil {
+				return nil, err
+			}
+			continue
+		}
+
 		if flags != nil {
 			if flags.Compression {
 				_, err = read7BitChunkedInt(r, 4) // read 4

id3v2frames.go

@@ -119,6 +119,7 @@ var id3v23Frames = map[string]string{
 	"SYTC": "Synchronized tempo codes",
 	"TALB": "Album/Movie/Show title",
 	"TBPM": "BPM (beats per minute)",
+	"TCMP": "iTunes Compilation Flag",
 	"TCOM": "Composer",
 	"TCON": "Content type",
 	"TCOP": "Copyright message",
@@ -152,6 +153,8 @@ var id3v23Frames = map[string]string{
 	"TRSN": "Internet radio station name",
 	"TRSO": "Internet radio station owner",
 	"TSIZ": "Size",
+	"TSO2": "iTunes uses this for Album Artist sort order",
+	"TSOC": "iTunes uses this for Composer sort order",
 	"TSRC": "ISRC (international standard recording code)",
 	"TSSE": "Software/Hardware and settings used for encoding",
 	"TYER": "Year",
@@ -209,6 +212,7 @@ var id3v24Frames = map[string]string{
 
 	"TALB": "Album/Movie/Show title",
 	"TBPM": "BPM (beats per minute)",
+	"TCMP": "iTunes Compilation Flag",
 	"TCOM": "Composer",
 	"TCON": "Content type",
 	"TCOP": "Copyright message",
@@ -246,7 +250,9 @@ var id3v24Frames = map[string]string{
 	"TRCK": "Track number/Position in set",
 	"TRSN": "Internet radio station name",
 	"TRSO": "Internet radio station owner",
+	"TSO2": "iTunes uses this for Album Artist sort order",
 	"TSOA": "Album sort order",
+	"TSOC": "iTunes uses this for Composer sort order",
 	"TSOP": "Performer sort order",
 	"TSOT": "Title sort order",
 	"TSRC": "ISRC (international standard recording code)",