This powerful shield features the VS1053, an encoding/decoding (codec) chip that can decode a wide variety of audio formats such as MP3, AAC, Ogg Vorbis, WMA, MIDI, FLAC, WAV (PCM and ADPCM). It can also be used to record audio in both PCM (WAV) and compressed Ogg Vorbis. You can even adjust bass, treble, and volume digitally. All this functionality is implemented in a light-weight SPI interface so that any Arduino can play audio from an SD card. There's also a special MIDI mode that you can boot the chip into that will read 'classic' 31250Kbaud MIDI data from an Arduino pin and act like a synth/drum machine with dozens of built-in drum and sample effects! This version of the shield only has stereo line/headphone output.