Thanks, I am home this morning so did some Googling, as I am really, REALLY good at buying computer stuff without fully understanding all the potential compatabilty issues.
I found some Display Port versions will not pass audio. It seems mine will.
From the factory Intel motherboard manual:
1.5.2.4 DisplayPort
DisplayPort is a digital communication interface that utilizes differential signaling to
achieve a high bandwidth bus interface designed to support connections between PCs
and monitors, projectors, and TV displays. DisplayPort is suitable for display
connections between consumer electronics devices such as high definition optical disc
players, set top boxes, and TV displays. DisplayPort output can also be converted to
HDMI using a DisplayPort-HDMI converter. The DisplayPort interface supports the 1.1a
specification.
DisplayPort’s maximum supported display resolution is 2560 x 1600 at 60 Hz refresh
with a 16:10 aspect ratio (WQXGA).
Table 5. DisplayPort Status Conditions
PCI Express x16 Connector Status DisplayPort Status
No add-in card installed Enabled
PCI Express x16 add-in card installed Enabled (Note)
Note: May require BIOS setup menu changes.
For information about Refer to
DisplayPort technology
http://www.displayport.org
1.5.2.5 Integrated Audio Provided by the DisplayPort Interface
The DisplayPort interface from the PCH supports audio. Table 6 shows the specific
audio technologies supported by the PCH.
Table 6. Audio Formats Supported by the DisplayPort Interface
Audio Formats DisplayPort
AC-3 - Dolby* Digital No
Dolby Digital Plus No
DTS-HD* No
LPCM, 192 kHz/24 bit, 8 Channel Yes
So it's probably worth me persevering and getting an adapter.
Longer term desire, that's rapidly shrinking to maybe I should just buy it now, is to build a newer PC. It appears some i9 Intel processors do NOT have integrated graphics. Is the lack of that an issue if I am using a separate video card that can do H256 compression, or should I make sure I get one that will also do in processor video?
How much memory do I need and is the very latest, fastest stuff worthwhile, or is something mainstream OK.
If I do bite the bullet I want a good amount of inbuilt future proofing. The PC will be pretty much initially be dedicated to DATV stuff.
I like, really like, Windows 7. I believe some or all of the newest motherboards and processors won't work, or have poor driver support for Windows 7. Does this mean I MUST MUST MUST use Windows 10 with its seemingly unstoppable updates that fiddle unwantedly with "stuff"? I am always seeing hams cursing about how it's interfered with their audio settings or whatever...
As to just how old this PC I am trying to run the H256 Chinese box on? Well, I'm not sure, but it is a Viglen Genie "medium" form factor box with an Intel DQ77MK motherboard, an Inteel i5-3470 processor, and 4 gig of DDR3 memory. So a bit of a dinosaur.
My best PC that's dedicated to the workshop is also now quite old, a Gigabyte H170-D3HP-cF motherboard with an Intel i7-6700K processor, and 16 gig of DDR4 memory. If I build an newer PC it would have to be substantially better than that so in time it could go into the workshop, where things are not dramatically demanding as it ages.