From Mystik Media:
AudioCommander is a configurable command-line and interface converter, encoder, and decoder for nearly all conceivable audio formats. Settings are provided for bitrate, frequency, and channels. Convert from AMR, MP3, WAV, WMA, OGG, AAC, AC3, AIFF, AU, VOX, RAW, PCM, ADPCM, A-LAW, u-LAW, MP2, FLAC, ALAC, CD, M4A, MP4, WavPack, and AVI audio to MP3, WMA, WAV, OGG, AAC, ADPCM, AIFF, AMR, A-LAW, u-LAW, or VOX. AudioCommander can be used to change the compression for supported formats; for example, compressing a 320 kbps MP3 to 128 kbps for use in a hardware device that requires a specific setting or does not support the higher bitrates. The comprehensive range of supported formats makes the software very flexible, and provides a complete solution for conversion of most any audio file desired. AudioCommander offers an extensive array of settings and command-line switches for complete control over how the software functions.