Help -- Extracting audio files from .iso file (Ratchet:Deadlocked, PS2)

[Doomification171]

Hi,

I'm having a bit of trouble ripping the music from one of my favourite PS2 games: Ratchet Deadlocked (2005). I have an .iso file (about 4 GB), but when I open it with WinRar, there are just a few files of only a few kB... From my understanding, these files are "indexes" to actually read the binary data from the disc (image), but my question is how to extract these files?

I already tried PSound (1.33), but for some reason it does not display all the files. After about 2 GB of data, it doesn't extract any more files. The next program I tried was Isobuster, but it isn't free software, and I don't want to pay 30$ for a program I'm going to use one time (pirating also didn't work for me; the program keeps asking for a license).

Can anyone recommend some free software that allows me to extract single audio files from an iso image like this one?

Thanks,
- D