Band in a Box can import standard MIDI files and convert them to BiaB format files. This is a useful feature because there are so many MIDI files available on the Internet, many more than are available in BiaB format.
Really Know the Song
The first, and probably most important, thing to do before trying to import a midi file into BiaB is get to know the song as well as you possibly can. Try to identify the style, number and type of instruments and especially any different parts. What makes the song identifiable? Is it the vocals, the bass, the lead guitar? You will need to know this in order to get the best sounding BiaB song you can.
The next most important thing is to find the best quality midi version of the song you are about to import. The more popular songs have been copied into midi by many different people and in many different ways. Some are little more than drum tracks with the vocal line played over it from a midi keyboard. Files of this type won't be very good as BiaB songs. Others have authentic sounding instrument tracks. This is what you are after. Remember, BiaB will ultimately be laying down five tracks for you, drums, piano, bass, guitar and strings. You only have two tracks with which to define the song, the melody and solo tracks so it's important to have the defining melody available for these tracks.
Store MIDI file
Once you've found the perfect midi version of your desired song download it to you local hard drive. Make sure it's in a sensible location you can find easily such as \My Documents\Midi Files\. It's important to have a local copy of the MIDI file in case of mistakes. That way you have an easily available backup.
Open the MIDI File
Now you can start to import the song into BiaB. By far the surest way is to open the midi file in BiaB using the File|Open midi File menu command. This will load the entire midi file into the melody track with all the original voices, controllers, pitch bends etc. It will also display the chords on the fakesheet as they were interpeted by BiaB. The key, time signature and tempo will also be displayed. If you play the midi now it should sound exactly as it did originally.
If you want or need a little more control over how BiaB interprets the chords use the File|Import chords from midi file command. This will give you a dialog that allows some control over the interpretation. For example you can choose to allow slash chords here. Make sure to check the import entire file to melody track option.
Identify the Tracks
The next step is to move the MIDI tracks (there can be up to 16 of them) one by one to the BiaB solo track and identify each one. Do this with the Edit|Copy/Move tracks command. De-select all the track check boxes. Set the controls to move track from melody to solo and select just track 1. Make sure the merge with existing data check box is not selected. Now click the Ok (do it) button. Track 1 will now be on the solo track with it's original voice. Mute the melody and play the song. You will hear only track 1 at this point and you can identify it by its voice and notes. You should view the solo track in standard notation here as an aid to identifying the track. Write down the track identity as you determine it. You will need this info later. Repeat this process untill you have identified all available tracks.
Newer versions of BiaB have a sequencer which will make the process of identifying the tracks much easier. Simply click on the SEQ button. Solo all the tracks one by one to identify them.
In addition, this feature would allow you to export the midi tracks as audio. Just mute all the tracks but one and close the sequencer dialog. Then right click the melody track and choose Output to wav.
Now for an example to help with picking the right tracks. Let's pretend we're importing 'House of the Rising Sun' and using the process above we've identified the all important guitar riffs on track 3 and the organ, including the distinctive solo, on track 14. The guitar can be imported to the melody track and voiced as a clean electric guitar. The organ can be imported to the solo track and voiced as a rock organ. So far so good.
We've also found a couple of other interesting tracks. Say track 1 has some fills voiced as some kind of synth. They could equally well be done by an overdrive electric guitar or an organ. So which track would we import this to? Well, if the fills are in bars where the guitar is quiet we could import this track to melody along with the guitar part and use patch changes to voice the fills as an overdriven guitar. Alternately we could import the track to the solo track and the fills will then be voiced as a rock organ and played along with the rest of the organ part. It is really personal preference here.
Suppose track 2 has the vocal part voiced as some kind of synth. Can and should we use this track? Generally I would say no don't use it. It sounds awkward to have the vocal part played by most voices. The only exception to this would be in the rare case where there isn't anything else that really defines the song. In these rare cases I would try to get the vocal track onto the solo BiaB track and voice it as Pad Halo or Brilliance etc. and set the volume low. This way it just hints at the vocals and doesn't sound too obtrusive. In the example here it might be possible to load the vocal track on the solo organ part and have the organ play the vocal part. Again this is personal preference.
Import the Chords
Ok, final step. Use the File|Import chords from midi file command again and this time tell BiaB to import track 3 and 1 to the melody and track 14 to solo. When you click the Ok (do it) button BiaB will re-import the tracks as you instructed.
Now you can listen to the BiaB version. It won't sound the same as the midi any more because BiaB is playing most of the instruments for you based on the selected style. Now, while the song is playing you should try to find a BiaB style that most closely resembles the original song. In the case of 'House of the Rising Sun' I'd try BritRok or 60Strum and work from there. If the time sig is 3/4 as it is in some versions you'll have to use a rock waltz style.