Songsmith, debuting Thursday at the International Consumer Electronics Show in Las Vegas, let's people explore songwriting "even if you don't know anything about music theory or chords and you never thought you'd write a song in your whole life," said Dan Morris, who helped develop it.

The software first analyzes your vocal melody using existing pitch-tracking technology. Then an algorithm the researchers built selects musical chords that will go well with the melody. The algorithm uses approximate statistical rules, developed by analyzing a database of about 300 songs, to determine the chords that sound good with different melodies, and each other.

"So then when we get a new melody, we can use the rules to generate new chords to go with that melody," he said.

Songsmith incorporates technology from PG Music -- a Victoria, British Columbia company that makes software called Band-in-a-Box -- to automatically play the musical accompaniment in a variety of styles. People can set the software to match different moods and play around with the chords to refine their music.

Songsmith doesn't produce "a professional, Grammy-winning recording, but it is going to sound musical and it's going to give non-musicians that sense of musical creativity," Morris said. He expects people to share their songs with friends and create music videos to post on YouTube.

The product evolved from MySong, a joint research project by Microsoft researchers Morris and Sumit Basu, and Ian Simon, a University of Washington computer science graduate student who worked with them as an intern in 2007. All three are music loves and hobbyist musicians. Morris and Simon play together in a local '80s cover band called Rewind.

Simon, 29, said he was surprised to see his efforts as an intern evolve into a shipping product. (Songsmith is available for purchase at the Microsoft store for $29.95; a free time-limited trial is also available here.)

"This project was incredibly fun to work on," he said. "In three months, we got to make this thing that you sing into it and chords come out. ... I may have spent more time playing with what I was making than actually making it."

The songs

These are the raw vocals of a song called "Sarah and Me" (WMA file). And here's the same song after it being Songsmithed (again, WMA).

Want some more? Here's a song I wrote about the Consumer Electronics Show. Dan Morris sang it and Songsmithed it. The process took two minutes, he said. So here's our CES anthem: WMA.