The previous article touched on some basics of interfacing an I2S audio codec with the ESP32. This article will further outline the pinout and requirements.
Source: Interfacing an Audio Codec with ESP32 – Part 2
Interfacing an audio codec with ESP32 is easy and is supported by the hardware interface module integrated into the ESP32. The article here uses SGTL5000.
Source: Interfacing an audio codec with ESP32
Part 2 – http://grodansparadis.com/wordpress/?p=2702