SPI to I2S upgrade to 24 bit

Thanks for your reply, and hmm an interesting point you make, I just assumed that I2S was a standard in itself it didn't really occur to me to see if there were different formats. As for it being written in beginner HDL that's annoying specially as my knowledge of it is so basic, I'll have to check the converter datasheets and then see if I can work out what the code is doing exactly, unless you could outline it briefly? As you seem to be a fairly clued up person, would you mind just clarifying that this is the correct approach to getting audio quality ADC/DACs to communicate to usb.

ADC --> CPLD --> USB

USB --> CPLD --> DAC

I know usb audio interfaces are on the market but I can't figure out what their methodology is and the usb audio chips I've found have all been low quality audio for headsets and such like nothing 24 bit 192KHz

Thanks again for the response.

Dan