compress dolby or dts output over optical cable?

[ZorkNation]

NOTE: I don't know why my replies have not shown up yet. Waiting on the admins, I guess.

Hi Pro Tools Surround Output Experts,

My mobo is an Asus Z170 with Realtek High Definition Audio over optical TOSLink output. I have Sony Digital Surround DP-RF6500 headphones hooked up to the Realtek optical TOSLink output. When I play a video game or movie, it is able to send compressed DTS or Dolby Digital to the headphone base, which has indicator lights for the type of signal it receives. (DTS, Dolby Digital, or Dolby PLIIx). If it only receives L/R stereo, the indicators don't light up, but I still hear plain stereo. I was pretty sure this newer model actually has multiple transducers in each ear. Whether that, or if it functions through binaural sound field reproduction, it requires a compressed DTS, Dolby Digital, or PLIIx signal over the optical TOSLink cable. I know the driver is capable of producing it from software, since games worked. The test works. (See attached screenshots.)

I'm editing post sound on a film. Pro Tools requires an ASIO driver for video playback. (Incidentally... why?)

I found some ancient RealTek ASIO driver in a .cab file from the Microsoft driver archive. There is no ASIO software component in device manager to update the driver from like most of the instructions said. I tried "manual install" but nothing seemed to work. Some web page suggested using "Driver Easy" to install them but I don't want to pay $39 for something that potentially won't work. (Why the heck isn't there an easy way to install a .cab file?)

RealTek doesn't provide any audio drivers or utilities from their web site or Windows Store anymore, only through Windows Update. The audio drivers available on the Asus Z170 support page were also out of date and borkened the system so I couldn't set the audio control to DTS output at all. I had to reformat the system so I could reinstall the ones from Windows Update. It couldn't detect them again after manually installing the other ones even though they are newer. I don't think the ones from the Asus support page contained an ASIO driver.

I had to install ASIO4ALL to get video playback to work. Now I can't seem to switch the playback device back to the Windows Audio Device to see if that might work, even in a session with no video track. Regardless, I need to edit with video playback, so I guess ASIO4ALL is my only option. I installed the latest ("final") version of the driver.

When I set up a new output path, I can see six channel analog, but only 2 channels for S/PDIF. (The Realtek on the mobo has 3 stereo mini outputs for 6-channel analog next to the optical TOSLink output jack.) If I set up the stereo output, and direct my stereo mixdown bus to it, I can hear stereo in the headphones.

There doesn't seem to be any way to route 5.1 to that optical TOSLink output. Is that a limitation of the ASIO4ALL driver? Is there another output device to encode Dolby Digital, PLIIx, or DTS and send it out through optical? I know it can work in theory because video games can do it.

Any suggestions for getting these headphones to work would be great. I only paid $200 for the $1000 set from some schmo on Craigslist, but they are really awesome. I do have a set of 5.1 speakers that I can hook up to get the work done, but I'd like to be able to work on headphones.

Thanks so much for your input.
Mark