ffmpegのnellymoserデコーダー試そうと思っていろいろみてたら
Google Summer of Code 2008で
Title Nellymoser Encoder

abstract: The Nellymoser Asao codec is a proprietary single-channel (mono) format optimized for low-bitrate transmission of audio, developed by Nellymoser Inc. The codec optimized for real-time and low-latency encoding of audio. Adobe Flash Player clients, when recording audio from a user’s microphone, use the Nellymoser Asao codec and do not allow Flash programmers to select any other codec. My main goal will be writing Nellymoser encoder.

というのを発見。
期待