VS1053b is a single-chip Ogg Vorbis/MP3/AAC/- WMA/MIDI audio decoder and an IMA ADPCM and user-loadable Ogg Vorbis encoder. It contains a high-performance, proprietary low-power DSP processor core VS DSP4, working data memory, 16 KiB instruction RAM and 0.5+ KiB data RAM for user applications running simultaneously with any built-in decoder, serial control and input data interfaces, upto 8 general purpose I/O pins, an UART, as well as a high-quality variable-samplerate stereo ADC (mic, line, line + mic or 2£line) and stereo DAC, followed by an earphone amplifier and a common voltage buffer.