VS1053b is a single-chip Ogg Vorbis/MP3/AAC/-WMA/MIDI audio decoder and an IMA ADPCMand user-loadable Ogg Vorbis encoder. It containsa high-performance, proprietary low-power DSPprocessor core VS DSP4, working data memory,16 KiB instruction RAM and 0.5+ KiB data RAMfor user applications running simultaneously withany built-in decoder, serial control and input datainterfaces, upto 8 general purpose I/O pins, anUART, as well as a high-quality variable-sampleratestereo ADC (mic, line, line + mic or 2£line)and stereo DAC, followed by an earphone amplifierand a common voltage buffer.