iOS native QRCode scanner in Chinese Encoding

This QRCode creates by Chinese Big5 Encoding not UTF-8, I am using iOS native class, AVMetadataMachineReadableCodeObject, try to get the result, but the string unreadable, like following:

**·s¦¡Àô«O­I:1:2:¯Â³ð¯ùºñ¯ù:2:20:¨Å­»¥@®a¥þ:1:83:­ìµÑ¤é¦¡ºñ:2:25:¥Í¬¡ªwªjºñ:2:10

I tried to convert the string to NSData by UTF-8, then I convert again from NSData to NSString, by others Encoding, and I thnik the original string already get wrong encoding that is why I can convert to the correct string.

This is correct content:

**新式環保背:1:2:純喫茶綠茶:2:20:乳香世家全:1:83:原萃日式綠:2:25:生活泡沫綠:2:10

Does any way to get correct result using iOS native class? thanks