How to read Id3v2 tag

问题

static void Main(string[] args)
{
    FileStream fs = File.Open(@"C:\Skrillex - Rock n' Roll (Will Take You to the Mountain).mp3", FileMode.Open);
    BinaryReader br = new BinaryReader(fs);

    byte[] tag = new byte[3];
    byte[] version = new byte[2];
    byte[] flags = new byte[1];
    byte[] size = new byte[4];
    byte[] frameId = new byte[4];
    byte[] frameSize = new byte[4];
    byte[] frameFlags = new byte[2];

    br.Read(tag, 0, tag.Length);
    br.Read(version, 0, version.Length);
    br.Read(flags, 0, flags.Length);
    br.Read(size, 0, size.Length);
    br.Read(frameId, 0, frameId.Length);
    br.Read(frameSize, 0, frameSize.Length);
    br.Read(frameFlags, 0, frameFlags.Length);

    ulong iSize = (ulong)frameSize[0] << 21 | (ulong)frameSize[1] << 14 | (ulong)frameSize[2] << 7 | (ulong)frameSize[3];
    Console.WriteLine("Frame Data Size : " + iSize.ToString());

    byte[] body = new byte[iSize];
    br.Read(body, 0, body.Length);
    Console.WriteLine(BitConverter.ToString(body));
    Console.WriteLine(ConvertHexToString(BitConverter.ToString(body)));

    br.Close();
}

public string ConvertHexToString(string HexValue)
{
    string StrValue = "";
    HexValue = HexValue.Replace("-", "");
    while (HexValue.Length > 0)
    {
        StrValue += Convert.ToChar(Convert.ToUInt32(HexValue.Substring(0, 2), 16)).ToString();
        HexValue = HexValue.Substring(2, HexValue.Length - 2);
    }
    return StrValue;
}

I am writing the code for reading ID3v2.3 tags without external library or Shell32.

The above code is that code, but it seems not to work properly.

The following is the result when I run the code:

Frame Data Size : 91

01-FF-FE-52-00-6F-00-63-00-6B-00-20-00-6E-00-27-00-20-00-52-00-6F-00-6C-00-6C-00-20-00-28-> 00-57-00-69-00-6C-00-6C-00-20-00-54-00-61-00-6B-00-65-00-20-00-59-00-6F-00-75-00-20-00-74-> 00-6F-00-20-00-74-00-68-00-65-00-20-00-4D-00-6F-00-75-00-6E-00-74-00-61-00-69-00-6E-00-29-00

ÿþR

It is not returning the song title "Rock n' Roll (Will Take You to the Mountain)" that was recorded in the tag.

What is problem?

回答1:

The 01 at the start indicates that it is encoded as UTF-16 (2 bytes per character). The next two bytes, FF FE, are the byte order mark so you can tell whether to interpret the byte pairs as most significant first or least significant first. After that you have the actual text data.

0052 - R
006F - o
0063 - c
006B - k

etc.

来源：https://stackoverflow.com/questions/16399604/how-to-read-id3v2-tag