Those who took a liking to the downloadable PSP game Beats by SCEE London may want to try Beats Off, a homebrewed spin-off by JBrown where you can load custom compiled BJS files. One of the good things about this piece of homebrew is that it's good for several  platforms aside from the PSP - Windows, Linux, and even Mac OS X.

The homebrew download includes an application where you can make tracks and pages out of VAG files. The application will also solve the problem of having to create working BJS files.

The project isn't without its drawbacks though, which are outlined here in the homebrew developer's detailed notes:

• The BAR file created must replace an already existing Jam BAR.
  This is due to a single damn value in the header that I can't figure out how to generate. JAM_0002 is the victim right now, though I quite like this Jam, so I might change it later.
  
• User needs to convert audio files to VAGs themselves.
  I'm not about to get into the business of file conversion, so I recommend Awave Audio for batch converting the dozens of files you'll need to make a decent Jam. Once this is done, however, my application includes a tool for batch modifying the VAG headers for use in Beats.
  
• User must know how to unpack, modify and repack the Beats ISO.
  If you've purchased Beats (please do), you can convert it to an ISO using NP Decryptor. From here you must extract the contents of the ISO, replace the proper folder, then repack the ISO and copy it over to your PSP. I use Prometeus for OS X to do the unpacking/repacking, but I'm sure there are other apps for other platforms.
• All loops must be 4 bars long.
  Beats allows for use of various sized loops, but right now it's locked in at 4. The duration of the main loop and time signature are also locked in at 4. This is an easy enough fix, I just need to create a better UI.
  
• XML is not generated yet.
  More laziness on my part: While the names created in the BJS will show up in Jamming mode, they will not show up in the menu; there will be a blank (but selectable) entry.
• No samples yet.
  At first I didn't think much of the samples in Beats, as they seemed to lag when you triggered them (either that or I have less rhythm than I thought). A little more complicated to add, but might be worth it for triggered effects.
• No cover art yet.
  The image format used by Beats is slightly different than what's normally used by, say, the XMB. My few attempts to create a custom image have failed, and at the moment this isn't my highest priority.
• I'm not a programmer.
  Other than the mess of amateur code under the hood (source available soon), there are probably some bugs, as I haven't thoroughly tested this. In fact, the Linux build is completely untested.

As with all other homebrew application and games, it is always a good idea to check out the accompanying readme file before installing the game. The homebrew developer also has a caveat: use at your own risk. Do be careful in tinkering with Beats Off, but don't forget to have fun!

Download: Beats Off v0.1