We know that Hitachi uses the NEC1 IR protocol. The document shows AV1 as 50AF 21DE  The  left 2 (hexadecimal) digits are the device number: 50 hex or 80 in decimal notation.  The AF is the binary complement of 50, so 50 +AF add to FF.  This is the standard NEC approach, so it is only necessary to specify the first 2 digits.  The function number is 21 hex or 33 in decimal.

You can convert 50 21 to Pronto Hex using www.monmailbox.com/~raph//irhex_converter.html.  Don't worry that it says Yamaha; both companies use NEC1.
It should look like
0000 006D 0022 0002 0155 00AA 0015 0015 0015 0015 0015 0015 0015 0015 0015 0040 0015 0015 0015 0040 0015 0015 0015 0040 0015 0040 0015 0040 0015 0040 0015 0015 0015 0040 0015 0015 0015 0040 0015 0040 0015 0015 0015 0015 0015 0015 0015 0015 0015 0040 0015 0015 0015 0015 0015 0015 0015 0040 0015 0040 0015 0040 0015 0040 0015 0015 0015 0040 0015 0040 0015 05ED 0155 0055 0015 0E47

More generally, you can use MakeHex and the MakeHex GUI to generate the Pronto Hex for nearly any IR protocol (not just NEC).
MakeHex
Makes clean IR sequences from IR protocol files. See the readme file for more information. [Link: hifi-remote.com]
MakeHex GUI[Link: hifi-remote.com]]