/// <summary>
/// Creates an ID3v2 frame for the given key-value pair.
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
/// <returns></returns>
private static byte[] CreateId3v2Frame(string key, string value)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentNullException("key");
}
if (string.IsNullOrEmpty(value))
{
throw new ArgumentNullException("value");
}
if (key.Length != 4)
{
throw new ArgumentOutOfRangeException("key", "key " + key + " must be 4 characters long");
}
const byte UnicodeEncoding = 01; // encode text in Unicode
byte[] UnicodeOrder = new byte[] { 0xff, 0xfe }; // Unicode byte order mark
byte[] language = new byte[] { 0, 0, 0 }; // language is empty (only used in COMM -> comment)
byte[] shortDescription = new byte[] { 0, 0 }; // short description is empty (only used in COMM -> comment)
byte[] body;
if (key == "COMM") // comment
{
body = ByteArrayExtensions.Concat(
new byte[] { UnicodeEncoding },
language,
shortDescription,
UnicodeOrder,
Encoding.Unicode.GetBytes(value));
}
else
{
body = ByteArrayExtensions.Concat(
new byte[] { UnicodeEncoding },
UnicodeOrder,
Encoding.Unicode.GetBytes(value));
}
return(ByteArrayExtensions.Concat(
// needs review - have converted to UTF8 as Win 8 has no Encoding.ASCII,
// need to check what the rules are for ID3v2 tag identifiers
Encoding.UTF8.GetBytes(key),
FrameSizeToBytes(body.Length),
new byte[] { 0, 0 }, // flags
body));
}
/// <summary>
/// Creates the Id3v2 tag header and returns is as a byte array.
/// </summary>
/// <param name="frames">The Id3v2 frames that will be included in the file. This is used to calculate the ID3v2 tag size.</param>
/// <returns></returns>
private static byte[] CreateId3v2TagHeader(IEnumerable <byte[]> frames)
{
int size = 0;
foreach (byte[] frame in frames)
{
size += frame.Length;
}
byte[] tagHeader = ByteArrayExtensions.Concat(
Encoding.UTF8.GetBytes("ID3"),
new byte[] { 3, 0 }, // version
new byte[] { 0 }, // flags
GetId3TagHeaderSize(size));
return(tagHeader);
}