Can the arduino function as a USB to I2s converter?
If so how does one go about doing this?
Yes, but the details matter... For what purpose?
You can read data into the USB port and there is a library for writing I2S. Depending on your needs you might have to do some "conversion" or "translation" but otherwise the Arduino code is probably not too difficult.
The Arduino USB "looks like" a COM port to the computer, so the computer would have to write to the COM port and you'd have to write a computer application for that.
And, there could be speed limitations depending on how much throughput you need.
Sorry I should have mentioned the intention.
I want to use it as an audio feed into a DAC. I don't need it to be high quality or anything, I just need it for troubleshooting purposes. I need to find out if the DAC will output a signal if I feed it an I2S audio signal.