diff --git a/youtube_dl/aes.py b/youtube_dl/aes.py
index 9913d59a4e..9a0c93fa6f 100644
--- a/youtube_dl/aes.py
+++ b/youtube_dl/aes.py
@@ -3,7 +3,7 @@
 import base64
 from math import ceil
 
-from .utils import bytes_to_intlist
+from .utils import bytes_to_intlist, intlist_to_bytes
 
 BLOCK_SIZE_BYTES = 16
 
@@ -118,7 +118,7 @@ def next_value(self):
             return temp
     
     decrypted_data = aes_ctr_decrypt(cipher, key, Counter())
-    plaintext = ''.join(map(lambda x: chr(x), decrypted_data))
+    plaintext = intlist_to_bytes(decrypted_data)
     
     return plaintext