I just had to to use esp-open-sdk toolkit.
sudo ./configure --target=xtensa-lx106-elf --host=xtensa-lx106-elf && sudo make
or for fixed point math (better performance and lower latency, but lower quality)
sudo ./configure --target=xtensa-lx106-elf --host=xtensa-lx106-elf --enable-fixed-point && sudo make
The compilation will throw prototype warnings, just ignore them. The compiled files will be in opus.1.1.2/src/
To do :
- test performance/memory usage
- create I2S reference implementation with opus
- implement stereo 10-bit DAC with 2 GPIO pins with PWM/sigma-delta or mono 1-bit sigma-delta DAC with SPI pin at 1Mhz.