I posted my method on the main modding forums. I am posting it here to make it easier to find for interested modders of this game.
this method of mine will only work for the ps3 version until someone finds the filelists for the zone files in the PC version or tell me how it works in the PC version.
I downloaded the ps3 version of this game from a pirate site and which site and all, I will not be mentioning here for obvious reasons. now in the ps3 version, wht I did was unpack the filelist2e.ps3.bin and the white_img2e.ps3.bin with the noesis tool. (plz note tht the e might mean my game is a europe version).
next inside the unpacked folder tht noesis will create, there's a zone folder and inside tht, the filelists for the zone bin files r present. after unpacking all of the zone files, with the correct filelists, I found tht the music files r all packed inside this zone file white_z0120e_img.ps3.bin
Now inside the unpacked white_z0120e_img.ps3.bin folder, I copied all the music files stored in .scd format, to another folder and tried to convert them using vgmstream. this vgmstream of mine is an older version which I failed to realize. while converting, some files failed to convert. after converting the files to .wav format, I noticed tht a lot of tracks played in the game r missing in the .wav converts. I quickly tried to convert the failed files in the vgmstream but failed.
Now I got curious as to whether these files were encrypted or programmed differently and so I goggled abt encrypted scd files, which led me to a github page dealing with a similar topic. from this page I managed to get to another vgmstream, which supposedly fixed some issues for this game's xbox version files.
I downloaded this new vgm and tried to unpack one of the failed files. wonders it extracted. i had to do all of them seperate, since this new vgm did not allow me to group convert. After the files got converted to .wav files, I listened to the tracks and found all of them with dual audio tracks which will play simultaneously. opening audacity confirmed my doubt as I found two set of tracks. muting one set and I could hear either of the tracks clearly. these tracks all had two themes. one tht will play while u r just walking and one tht will play if u encounter an enemy in game. this switching bewteen two tracks is wht SE started using from FF 13-2. this time they did the same, but with a different coding to the .scd files which my older vgmstream wihich worked for the previous two XIII games failed to work.
so yeah I was kinda successfull, but the real success for me is to unpack the PC version's white_z0120a_img.win32.bin and white_z0120v_img.win32.bin files. for opening these files like i said we need the related filelist. one guy who created a entire guide on preparing this game's files for modding said the same. thanks to him and his modding guide. it helped me a lot in figuring these files.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=887455203