Incorrect ID3 synchronized lyrics (SYLT) data.

[probityrules]

When I use this library to parse synchronized lyrics from an mp3, I get a single array with corrupted data like this:

//common.lyrics
[
    "揾愀瀀琀椀漀渀猀",
    "Check out your sash!",
    "",
    "揾愀瀀琀椀漀渀猀",
    "Check out your sash!",
    "",
    "泾椀瀀猀礀渀挀",
    "X",
    "＀䛾",
    "渀C",
    "８䛾",
    "币B",
    "Ｐ䏾",
    "瘂B",
    "ￔ壾",
    "怄"
]

But in this example it should be a 2d array (3 arrays of synchronized lyric data) with data something along these lines (per https://id3.org/id3v2.3.0#Synchronised_lyrics.2Ftext):

[{
    "language": "eng",
    "timeStampFormat": 2,
    "contentType": 2,
    "shortText": "captions",
    "synchronisedText": [{
        "text": "Check out your sash!",
        "timeStamp": 9
    }]
}, {
    "language": "eng",
    "timeStampFormat": 2,
    "contentType": 2,
    "shortText": "captions",
    "synchronisedText": [{
        "text": "Check out your sash!",
        "timeStamp": 9
    }]
}, {
    "language": "eng",
    "timeStampFormat": 2,
    "contentType": 0,
    "shortText": "lipsync",
    "synchronisedText": [{
        "text": "X",
        "timeStamp": 0
    }, {
        "text": "F",
        "timeStamp": 110
    }, {
        "text": "C",
        "timeStamp": 280
    }, {
        "text": "F",
        "timeStamp": 350
    }, {
        "text": "B",
        "timeStamp": 560
    }, {
        "text": "C",
        "timeStamp": 630
    }, {
        "text": "B",
        "timeStamp": 980
    }, {
        "text": "X",
        "timeStamp": 1120
    }]
}]

(I realize the first two repeat which is an error on my end and doesn't match the last line of the spec:

There may be more than one "SYLT" frame in each tag, but only one with the same language and content descriptor.

but it does exhibit the issue of not correctly unpacking a list of multiple synchronized lyric sets.

[Borewit]

Please provide a sample.

[probityrules]

Here's an mp3 with two embedded SYLT's - "captions" and "lipsync"
menu-sash.zip

[Borewit]

Issue confirm, there are number of shortcomings and limitations in the ID3v2 SYLT frame decoding.

[Borewit]

I have difficulties to detect the difference between shortText and synchronisedText

[probityrules]

The shortText/descriptor would be a variable-size string that terminates with 0x00 and if it's an empty, it's just a standalone 0x00. In both cases after the 0x00 is the first synchronized text (ie a another variable-size string terminated by 0x00) and timestamp (32bit I think), which then repeats (string, timestamp, string, timestamp) until end of frame.

[Borewit]

Got it, first portion is shortText / Content descriptor, terminated by $00 / $0000
After that a list synchronisedText / syllable, terminated by $00 / $0000, and each entry followed by timestamp $XXXX.