Here is my collection of the motets and rondeaux of Adam de la Halle. I only set the polyphony because it's metrical and so is better suited to a mechanical reproduction.
I transcribed these pieces from the original notation (Well, OK, from a facsimile of a copy of the original notation, as found in Oeuvres Complètes du Trouvère Adam de la Halle, published in Paris in 1872), after studiously reading and rereading the pertinent chapters in The Notation of Polyphonic Music 900-1600 by Willi Apel.
You will notice that there are two versions of most of the songs. This is because I was wishy-washy on the value of the semibreve, and couldn't decide whether to make it equal to one-half of a breve, as it had been in the first part of the thirteenth century, or equal to one-third or two-thirds of a breve, as was declared by Franco of Cologne in Ars cantus mensurabilis.
So I set every piece that has semibreves both ways. You can decide for yourselves which you prefer.
I set the music in abc notation. I created the midi files with abc2midi, and the pdf files with jacabc2ps and ImageMagick. (I modified jcabc2ps slightly to make it easier to set motets.)