Another computer stupidity?

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Rikkitic

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#191308 31-Jan-2016 17:21

This is partly a rant, and partly a plea for help. When fiddling with computers, I often seem to run into issues that make me wonder about the common sense of the hardware and/or software designers. Sometimes these issues have good reasons that are hidden to me due to ignorance and lack of understanding on my part. Other times, though, they just leave me scratching my head in bewilderment.

Here is the latest example: I am trying to set up a streaming computer with 5.1 channel surround sound through the HDMI port. All the drivers I can find correctly say that the audio is digital HD, but then they insist on setting it to 2-channel stereo. I have been battling this for days, and apparently it is a widespread problem. Some of it seems to be the fault of Windows (nothing new there) but some also seems to be due to a stunning lack of perception on the part of graphics card programmers. At least, that is my impression.

What I don't get is why these cards (many different manufacturers, if not all of them) have no options whatsoever to override automatic assumptions and manually set things the way you need them to be. This is incredibly frustrating, not only to me. The problem in my case, as well as others, is that I want to feed the HDMI signal to a TV (Sony) that then passes the audio on to my amp via a toslink cable.

From what I understand, the audio software sees the TV, with two speakers, but not the pass-through cable, with digital audio, so sets itself to stereo out with no possibility to correct that. Am I missing something or are the designers really that stupid? In any case, the result is that I can find no way to override this. There are workarounds to be sure, such as running a digital audio cable from the computer directly to the amp, but I think it is ridiculous to have to resort to this kind of thing when there is already a perfectly good digital audio signal going into the HDMI connector.

Is there a way to fix this? I would be grateful to know.

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#1482342 31-Jan-2016 17:39

They will only output what the TV reports it is able to handle. Check the EDID of the TV if it says it can do multichannel. Most cannot, and at best will pass a bitstream from the HDMI over to the optical out, but really you should be going from the PC to the reciever over HDMI and then onto the amp so it can support multichannel audio.

Bitstream over HDMI is so limited and useless that its not really that well supported for legacy codecs that will output over optical.

Richard rich.ms

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#1482355 31-Jan-2016 18:01

richms:
They will only output what the TV reports it is able to handle. Check the EDID of the TV if it says it can do multichannel. Most cannot, and at best will pass a bitstream from the HDMI over to the optical out, but really you should be going from the PC to the reciever over HDMI and then onto the amp so it can support multichannel audio.

Bitstream over HDMI is so limited and useless that its not really that well supported for legacy codecs that will output over optical.

Yip, nothing to do with the PC. The TV will only output multi zone audio from freeview or its own apps. It's not an HDMI pass through device.

Dunnersfella

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#1482363 31-Jan-2016 18:35

EDID issue, if the amp doesn't support HDMI then it's going to be down to a digital audio cable out of the computer, into the amp.

Remember that optical and digital coax cables can't take Dolby TrueHD, DTS Master HD, Dolby ATMOS or DTS X, they require HDMI connectivity.

Rikkitic

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#1482395 31-Jan-2016 19:29

Thanks for the replies. I’m not sure I understand all of it. I have tested the TV by running other sources through it, like the Blu-Ray player and the terrestrial STB, and the multi-channel audio seemed to work fine. With the STB I had some recorded 5.1 stuff that played back correctly. I checked it carefully to make sure it really was multi-channel.

Just passing a bitstream over to optical out is exactly what I think I want to do. At this stage I’m not trying to achieve anything fancy. I just want to be able to pass 5.1 Dolby digital to the TV with the HDMI connector and have it feed to the amp via the optical cable. If I can just get it to do that, I will be delighted.

I’m not sure I understand what you mean by “going from the PC to the receiver over HDMI and then onto the amp”. Isn’t that what I am trying to do? In this case the TV is the receiver and then I do pass the digital audio signal on to the amp via the Toslink cable.

Anyway, thanks again for helping with this. I am finding it a pure exercise in frustration.

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richms

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#1482398 31-Jan-2016 19:38

PCs are set up to typically decode the audio and output multichannel audio. Some playback software like VLC may be able to force it to output the bitstream directly from the source media to the sound device on your video card, but that means you have to have a source file that is fully compliant with what your reciever is expecting.

Since optical has no handshake then there isnt any way for the PC to know for sure what it can do so its reliant on what the TV says it is able to decode.

You really want to have HDMI into the reciever, and then the HDMI out of that to your television, the reciever will strip the audio off the signal before passing it along so what the TV supports is immaterial. Running optical from a TV back to a reciever is prettymuch redundant now since HDMI added audio return to it, which makes it all just work perfectly getting the sound from the TV's inbuilt player back to the reciever without any messing around with input switching etc.

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Rikkitic

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#1482407 31-Jan-2016 19:57

Now I understand. I should have made clearer that in this case, my television IS the receiver. I cannot afford to replace all of my equipment every couple of years to keep up with the latest developments. My amp is an old Yamaha that still works perfectly well and meets all my requirements, but does not have HDMI inputs. Instead, I use digital optical and coax for all the audio feeds. This has always worked perfectly well until now. It still works perfectly well except for this one very annoying problem. Is there no way just to fool Windows into thinking it is feeding a 5.1 capable device, which in fact it is? There are plenty of other things that only work correctly if Windows is hacked in one way or another. Surely this one must also be possible?

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richms

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#1482410 31-Jan-2016 20:04

If you have old gear then you will have to deal with the annoyances of not being able to use modern features in the way that they were designed.

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Rikkitic

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#1482412 31-Jan-2016 20:10

That's a fair point, but the computer, OS and graphics card are all about the same age as the amp (the TV is actually newer) so I would have had the same issue when they were all new.

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richms

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#1482425 31-Jan-2016 20:19

If you try VLC you might be able to force it to bitstream the audio that you are playing, but nothing anymore supports a real time encode of multichannel audio so you can forget being able to get multichannel sound happening over a toslink connection on windows. It will strictly be pre-encoded media playback, that is if it works at all.

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#1482440 31-Jan-2016 20:33

richms:
If you try VLC you might be able to force it to bitstream the audio that you are playing, but nothing anymore supports a real time encode of multichannel audio so you can forget being able to get multichannel sound happening over a toslink connection on windows. It will strictly be pre-encoded media playback, that is if it works at all.

I managed to do it with VLC, there's no HDMI on my reciever too. It took me a bit to work out how to get VLC to do it, but if you google it, should be in there.

I had lip sync issues through doing it that way, so have smart TV now that lets me plug a USB drive into it. Seems to play everything, and TV pass's DD and DTS to amp.

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#1482445 31-Jan-2016 20:48

I have a PC setup exactly this way. The HDMI connection goes into the 5.1 amp, and the amp goes to the TV. Set audio to HDMI, get direct Dolby/DTS pass through or decoded 5.1 stream depending on the software I'm using at the time.

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JimmyH

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#1482463 31-Jan-2016 21:51

There is probably a solution, depending on how much money you are willing to spend, and how fiddly you are prepared to make your setup.

I'm not an expert, but something like the HDMI audio extractor (Cat No: AC1741) that Jaycar sell for $109 might do the trick. It claims that it:

"Extracts the audio from HDMI and outputs to a 3.5mm socket or S/PDIF for connection to a set of speakers, home theatre audio system or amplifier. As some modern displays have less than desirable speakers, or no speakers at all, this will provide a simple way to connect audio up to a better sounding system. It supports video resolutions up to 4K x 2K and audio to 5.1CH digital. Comes with a 3.5mm to RCA audio cable."

It looks like it has HDMI pass-through for the TV, and will supply the 5.1 audio over optical to the amp. But it does involve spending a small amount of money and adding yet more cables into the setup.

Edit: Typo

richms

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#1482468 31-Jan-2016 21:56

The only way 5.1 travels over optical is as a compressed bitstream, so no, it will not help much at all.

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Rikkitic

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#1482565 1-Feb-2016 08:43

richms:

The only way 5.1 travels over optical is as a compressed bitstream, so no, it will not help much at all.

Can you explain this to me? I don't properly understand it. I use optical for other sources and it works fine. What is the difference in this case?

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PANiCnz

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#1482602 1-Feb-2016 09:51

Just get a cheap USB soundcard of DX.com with S/PDIF out and use that to output 5.1 directly to the amp. No need to muck around with passthrough etc then.

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