I used to do that 6-7 years ago in windows 98. I downloaded and tried the same tools now on XP and I just get errors and I can't even playback the .str files (the CDs/isos are fine). Any ideas? Does a "civilized" decoder for .str files even exist? I've been looking for one all night with no results :shrug:
Use PSX MC (Playstation Multi Converter), let's you scan discs/files for various old playstation formats (Movie Streams, Audio streams and Bitmap graphics, the later only in the latest non-freeware version, the other two are free in the old v2.XX lineup) and convert them to whatever you've set in your settings.
http://homepage2.nifty.com/~mkb/PsxMC/ There is a link for psxMC. That should still work (i used it ealier this year).