Hi! I´ve upgraded some time ago to WL Pro9 and so far I´m really happy with it. I´ve compiled a CD that I plan to send to replication. (Grateful for any advice on cheap but good quality handling in europe, by the way). However I cant find out what those codes are supposed to be or what they do, ISRC or UPC/EAN. How do I get them and what is required of me to do with them? Grateful fo some wise words of information. 
Blind as a bat… yours fransmo
It could be slightly different in the US but ISRC codes are a unique identifier for each song that can be provided by a number of people such as:
Mastering Engineer
Record Label
Digital Distributor
+more
I offer the option to my mastering clients to generate the codes for them, so we can be sure the codes are present on all master formats from the start. Sometimes with bigger artists, the record label provides the codes. Some clients also get a head start on the digital distribution and the digital distributor will assign a code for each song, which then I insert into the montage before making the final master files (DDP, CD-R, WAV, mp3 etc.)
I pay ISRC a certain amount of money each year to do this. You might learn more here:
http://www.usisrc.org/faqs/general.html
The UPC/EAN code usually comes from the CD manufacturer as it represents the barcode for the physical CD product. In the US at least, the cost is too high for me to justify having the ability to generate a UPC, but sometimes clients send me the UPC code they receive from their CD manufacturer and then I can add this to the montage before I render the final DDP or master CD-R for production.
It’s not essential that UPC or ISRC codes be on the master DDP/CD-R but some clients like to have all the complete info, and some don’t care.
Thanks for answering. Do I take it that these codes are not nessecary to bother about of you make a small release of 500 pcs or so?
/ yours Frans Mossberg
I think it’s really up to the client or whoever owns the music if they want this or not. UPC and ISRC codes are not required to be on a CD production master, but I find a wide range of scenarios where people think it’s absolutely necessary or some do not care at all.
Well, in terms of physical CDs, in the real world, you could make a compelling argument that they are of doubtful relevance in 2016 … even though every label and artist management group I work for always insists on it.
They are, on the other hand, very important for management of your digital life. It is, essentially, the way that product and royalties are catalogued and payments managed by the digital stores and streaming services.