I2S Data Structure (Inter-IC Sound)
I2S data for each sample is is the amplitude of that sample. It is sent MSB first. Typically data frames have 16, 24, or 32 bits per sample, and both devices must be configured to matching format. If you have 24-bit data from WAV file but 32-bit frames then data must be expanded correctly with zeroes. The WAV file most likely stores least significant byte first so perhaps some shifting or swapping is needed to send it. It should be pretty straightforward but depends on which MCU or DAC you are working on.