We have a custom board with ADV7611 - FPGA - ADV7513. Right now video is passing through and 1080P works. The monitor I'm testing has speakers that work when HDMI is connected directly to PC (nVidia Quadro), but no audio comes out when connecting our board between PC and monitor.
Pin 48 AP is broken out for audio from the ADV7611 and is connected to ADV7513 pin 3 SPDIF.
6-4b is the script we follow with added below configurations to use SPDIF not I2S and generate MCLK
68 01 02
72 0A 10
72 0B 8E
On the oscilloscope the ADV7611 AP pin has data streaming and data pattern changes if computer is muted or has music. And mute flag x65  reads 0. I think the problem has got to be with the settings of ADV7513. Am I missing something?