StarTech DVI2HD. Talked to the StarTech help line, and as usual, I'd already tried everything they suggested. And short of it being faulty, reckoned it was just a combatibilty problem. And I'm not going to change the TV or computers.
It's sad as it should have done everything I wanted in the simplest way. Powered by USB which also provided the audio, and the right DVI and HDMI connector.
I've returned it and ordered up a HMDI embedder at a higher cost which will also need adaptors.
LT8522EX
My guess is, DVI single lane output at 1920x1200 max CRTRB
165MHz comes into the chip, there is HDCP present, the signal is digitally scrambled, no sync can be extracted (DE or digital enable), and so a black screen is passed through to the output side at 330MHz.Usually, companies are forbidden from giving details of HDCP, even though the early version was cracked and the keys are known. There is probably a fee per dongle to be charged, if HDCP materials are included in the design. The only way you'd get a full datasheet, is under NDA.
I would test with some other potential signal sources, and see whether older or newer DVI kit, works with the thing.
The CM108 is a USB to stereo audio adapter, and it's part of your product too. They use the I2S bus interface on the CM108, to provide the USB audio to the design. All four pins of the USB interface are being used.
But unless the original digital signal is in plaintext (decrypted, no HDCP present), it's probably the front end of the chip that has "nothing but digital snow" to work with. Unless the device is equipped with either HDCP stripping or HDCP passthru, then some steps could be missing. Is the audio multiplexed in, covered by HDCP copy prevention ? Dunno.
How do you check out technical capability on a dongle like this ?
Dunno. There are various adjunct items on HDMI, but I don't know if they can be used in a plug and play sense, to give details of standards supported. Presumably something like that is required, when long chains of adapters are tied together in series. CEC flows backwards for control, but I don't know what additional information is sent that way.
Paul
I tried it with the only two DVI outputs I have. One from a pretty high spec PC and graphics card. The other, an aftermarket graphics card for the ancient Acorn called Viewfinder, and made by a cottage industry no doubt based on what was then commercially available for a PC etc.
I've no idea why HDCP signals should be present on a DVI video output from a PC.
So all the video chain I'm working with is DVI-D. The exception being the TV set working as a 'mirror' to the PC monitor. And that works just fine with a simple DVI-D to HDMI cable. The PC monitor is DVI_D too - and has a simple splitter to two DVI outputs, one of which fed the TV via the DVD to HDMI cable.
So it would appear this StarTech device (unless faulty) introduces the HDCP signal. As neither video or audio got through it.
I didn't know what HDCP is so I've just read the Wikepedia article about it. There is so much incredible complication there to stop some things and not others depending on connections, I'm not surprised you have unexplained effects.
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