VS1003 is a single-chip MP3 / WMA / MIDI audio decoder and ADPCM encoder.
It contains a highperformance, proprietary low-power DSP processor core VS DSP4, working data memory, 5 KiB instruction RAM and 0.5 KiB data RAM for user applications, serial control and input data interfaces, 4 general purpose I/O pins, an UART, as well as a high-quality variable-sample-rate mono ADC and stereo DAC, followed by an earphone amplifier and a common buffer.
VS1003 receives its input bitstream through a serial input bus, which it listens to as a system slave. The input stream is decoded and passed through a digital volume control to an 18-bit oversampling, multi-bit, sigma-delta DAC. The decoding is controlled via a serial control bus. In addition to the basic decoding, it is possible to add application specific features, like DSP effects, to the user RAM memory.
Unit price of VS1003 includes MP3 decoding license of Thomson. Customers who use WMA need to contact Microsoft.