MP3 on a single chip

Analog Devices has introduced what it claims is the industry’s first chipset to encode and decode MP3 on a single DSP chip.

The new Melody MP3 (MPEG1 Audio Layer 3) chipset encodes and decodes this Internet audio compression standard in real time using an Analog Devices’ fixed-point programmable ADSST-218xM DSP chipset. The Melody MP3 chipset also encodes and decodes MPEG1 Audio Layer 1 and 2 and fully complies with the ISO/IEC 11172-3 audio standard, the audio coding format standardized by the International Organization for Standardization (ISO) as part of the MPEG specification.

A new Melody MP3 reference design, also announced today, includes an ADSST-1885 stereo codec, enabling a complete MP3 player to be configured on a compact 85mm x 60mm x 30mm board and powered from two AA 1.5V batteries.

The Melody MP3 encoder and decoder run completely within the internal RAM of the DSP, requiring no external SDRAM/SRAM. The decoders support all of the bit rates and sampling frequencies specified by the encoding standard: half-sampling frequencies of 16, 22.05 and 24 kHz as well as full-sampling frequencies of 32, 44.1 and 48 kHz per channel.

All fixed bit rates are supported for both half and full sampling frequencies: 8 kbps to 160 kbps for half-sampling frequencies; 32 kbps to 320 kbps for full sampling frequencies. This includes support for both full and half-sampling rates at 96 kbps and 128 kbps. Post-processing includes a 5 dB bass boost and four equalizer functions for classical, pop, rock and jazz. Since the MP3 decoder requires less than 32 MIPS and the MP3 encoder less than 40 MIPS, the re-programmable DSP has sufficient processing power to decode other audio algorithms.

The Melody MP3 reference design, ADSST-DAP-EVAL01, includes the evaluation board, evaluation copy of the software, schematics and a demo. It is currently available from Analog Devices and priced in single quantities at $350.00. The Melody MP3 encoder/decoder chipset is currently available and priced at under $10.00 in volume quantities.

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