protected static byte[] readFully(InputStream inp, int length) throws IOException {
        return readFully(inp, length, true);
    }
AKA a Synchsafe integer.
4 bytes hold a 28 bit number. The highest
bit in each byte is always 0 and always ignored.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-audiovideo-module/src/main/java/org/apache/tika/parser/mp3/ID3v2Frame.java