decode

Reads a subtitle file's bytes as encoding, or answers null when this parser has no table for it.

The engine decides the encoding from the bytes, and asks only for the multi-byte East Asian ones: Shift_JIS, EUC-JP, GBK, Big5 and EUC-KR, as the WHATWG Encoding Standard names them. It may ask for all five for one file. It sets aside a reading with more than a little U+FFFD in it and weighs the rest by how likely their characters are, so a byte sequence the table cannot read must become U+FFFD. With the default null, such a file is read as single-byte text and the engine warns. An exception counts as null.