In 1999, after 10 years working with the same Ensoniq ASR-10 sampler, Ostertag switched to a laptop computer and began writing his own audio performance software through Max/MSP. This allows him use various controllers, including joysticks, game pads, and drawing tablets in his performances. This same year, Ostertag released "Like a Melody, No Bitterness" his first CD of solo improvisation. This CD is a tribute to his sampler that he spent the last decade mastering as an instrument. Ostertag has also scored multimedia pieces such as "Spiral" in 1996. In 2000, Ostertag began work with Pierre Hébert and Baltazar López on a full-scale multi-media and theater work, "Between Science and Garbage", commissioned by Meet the Composer and the Yerba Buena Center for the Arts in San Francisco.