This application note describes the ADPCM audio firmware codec, and provides a demonstration firmware showing how to play ADPCM files using the high-density STM32F103xx I2S feature with an external DAC.
The document details the implementation of the IMA ADPCM algorithm, which encodes 16-bit PCM samples into 4-bit ADPCM samples to achieve a compression rate of 4. It covers the general overview of the algorithm and describes two specific functions: `ADPCM_Encode` for coding audio and `ADPCM_Decode` for decoding.
| Audio format input | PCM |
|---|---|
| Audio sample size | 16 bits |
| Channels | 1 (mono) |
| Audio sample rate range | 8 kHz to 44.1 KHz |
| Compression rate | 4 |
The IMA ADPCM algorithm developed by the Interactive Multimedia Association.
The compression rate is equal to 4.
The implementation is designed for high-density STM32F103xx microcontrollers.