sqlite_udf_encode_binary() applies a binary encoding to the data so that it can be safely returned from queries (since the underlying libsqlite API is not binary safe).
If there is a chance that your data might be binary unsafe (e.g.: it
contains a NUL byte in the middle rather than at the end, or if it has and
0x01 byte as the first character) then you must
call this function to encode the return value from your UDF.
PHP does not perform this encode/decode operation automatically as it would severely impact performance if it did.