Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.
Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 


Glurp
8205 posts

Uber Geek
+1 received by user: 3780

Subscriber

  Reply # 1482605 1-Feb-2016 09:57
Send private message

I have decided to do something like that, but would still like to better understand the issue. Now I am trying to see if I can get an optical connection to work from spdif on the motherboard since coax won't work for my set-up.

 

 





I reject your reality and substitute my own. - Adam Savage
 


4580 posts

Uber Geek
+1 received by user: 2080

Trusted
Subscriber

  Reply # 1482608 1-Feb-2016 10:00
Send private message

Rikkitic:

 

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?

 

 

 

 

If your TV is decoding the audio already, then you can only use HDMI audio, because only the HDMI audio path can carry uncompressed multichannel audio. The optical connection can only carry the original encoded bitstream.

 

So, for example, I have the following setup (due to change any second):

 

     

  1. Denon receiver with HDMI to TV, has 2xHDMI and multiple coax and optical audio inputs available
  2. Computer with HDMI video and audio over HDMI into receiver
  3. XBox 360 with HDMI video and audio into receiver
  4. Bluray player with HDMI direct to TV and optical into receiver

 

The computer can either send a bitstream or decoded multichannel PCM to the receiver. The Bluray player can only send encoded bitstream over the optical link. Since my receiver pre-dates Bluray, that means I cannot take advantage of the HD DTS stream (it falls back DVD-quality DTS via some clever hackery - look it up). 

 

Once I get a power supply to replace the US one it came with, I'm going to put all those through an HDMI switch. I will then set the Bluray player to PCM to (hopefully) get the HD DTS stream uncompressed over the HDMI audio channel. And at least, if not, I only have one remote to play with when switching between the Bluray player and anything else.

 

 





iPad Air + iPhone SE + 2degrees 4tw!

These comments are my own and do not represent the opinions of 2degrees.


622 posts

Ultimate Geek
+1 received by user: 41


  Reply # 1482609 1-Feb-2016 10:00
Send private message

Rikkitic:

 

Now I am trying to see if I can get an optical connection to work from spdif on the motherboard since coax won't work for my set-up.

 

 

That should also work, no need to get the USB soundcard then.

 

5.1 audio pass-through on TVs is very hit and miss, the fact you haven't had any issues to date is more to do with luck. A quick Google will show very few TV's support the feature. Ultimately you're better off send the audio directly to the receiver it'll give far less issues in the long run.

 

 


21450 posts

Uber Geek
+1 received by user: 4354

Trusted
Subscriber

  Reply # 1482671 1-Feb-2016 11:16
Send private message

A bitstream is compressed audio. What is on a dvd is a dolby digital compressed stream alongside a compressed video stream.

The bitrate is low enough to fit over optical connections.

Decoded multichannel is 6 or 8 uncompressed audio channels. Will not fit on HDMI. This is what windows makes when it outputs all the audio from the computer and you tell it you have 5.1 or 7.1 speakers. Only way to fit it on a optical cable is to compress it. That means licensing costs which no manufacturer wanrs to pay for something that will almost never be used. Also adds latency and degrades the audio as it is heavy and quite old compression.




Richard rich.ms



Glurp
8205 posts

Uber Geek
+1 received by user: 3780

Subscriber

  Reply # 1482694 1-Feb-2016 11:38
Send private message

Thank you very much for that explanation, richms. Now it makes sense to me. I just like to understand why things are a certain way when there doesn't seem to be a good reason for it.

 

 





I reject your reality and substitute my own. - Adam Savage
 


4580 posts

Uber Geek
+1 received by user: 2080

Trusted
Subscriber

  Reply # 1482793 1-Feb-2016 13:36
Send private message

richms: 
Decoded multichannel is 6 or 8 uncompressed audio channels. Will not fit on HDMI.

 

HDMI does allow uncompressed multichannel audio.





iPad Air + iPhone SE + 2degrees 4tw!

These comments are my own and do not represent the opinions of 2degrees.


21450 posts

Uber Geek
+1 received by user: 4354

Trusted
Subscriber

  Reply # 1482862 1-Feb-2016 14:47
Send private message

SaltyNZ:

 

richms: 
Decoded multichannel is 6 or 8 uncompressed audio channels. Will not fit on HDMI.

 

HDMI does allow uncompressed multichannel audio.

 

 

 

 

crap, meant optical when i typed it then moved stuff around,





Richard rich.ms



Glurp
8205 posts

Uber Geek
+1 received by user: 3780

Subscriber

  Reply # 1485941 5-Feb-2016 14:23
Send private message

I want to return to this topic. I know many people view these threads and some may benefit from what I have learned. Others may be able to help with what I still don’t understand.

 

After the explanations kindly provided here, I could see why my audio wasn’t working the way I wanted it to. However, I was convinced that there ought to be a way to make it work, since all the ingredients seemed to be present. So I went looking for more answers.

 

First, I added an optical connector to the S/PDIF header on my motherboard and made sure it was working. Then I spent a lot of time reading some of the many, many posts on this topic. Eventually I came across a site with a lengthy thread devoted to this specific issue. Apparently I am not the only one wanting digital multi-channel sound from my computer. The thread I found includes modified Realtek drivers to enable surround sound and detailed discussions of these. It is located here: http://www.techpowerup.com/forums/threads/unlocked-realtek-hd-audio-drivers-with-dolby-digital-live-and-dts-interactive.193148/.

 

I had a lot of trouble getting this to work and it took a lot of fiddling, but eventually it did, at least after a fashion. There seem to be different issues that can get in the way and these seem to vary according to the motherboard and drivers used. One is PUMA, the protected audio mode that prevents a modified DLL from working as it should. There are ways around this, none of them ideal. I ended up placing both the original and modified DLL in the System32 folder, and switching between them by renaming. For some reason I only had to do this once. After the surround channel LEDs magically lit up on my amp, they continued to work even after I put the original DLL back and rebooted.

 

To simplify diagnostic issues, I used a DVD with Dolby 5.1 audio for testing. Once I finally worked out the above, it started playing as it should, with full surround, though the test button on the Realtek driver still only produces stereo. I was quite pleased to get this far, but I do notice frequent brief breaks in the audio, which I assume are due to the on-board processor not being able to keep up with the increased demands of the 5.1 stream.

 

In spite of this my ultimate goal remains to enable 5.1 Internet streaming. This is where I am currently stuck, and I would welcome helpful suggestions. To avoid browser issues, I have been using VLC with some 5.1 test streams on YouTube, but I can’t get it to work. Regardless of the settings I try, the audio codec always comes back as 2-channel MP4a. This in spite of the fact that my amp is still showing 6 channels and the videos I am trying to stream are 5.1 test videos. I’m not sure why this is happening since I am definitely getting 5.1 through the optical cable from the computer and I have changed every VLC setting I can find to make it use Dolby surround. This is the issue I would now appreciate help on. I hope others get some benefit from the rest of what I have written here.

 

[edited layout - my word processor still can't cope with Geekzone]

 

 

 

 

 

 





I reject your reality and substitute my own. - Adam Savage
 


1845 posts

Uber Geek
+1 received by user: 675

Lifetime subscriber

  Reply # 1485950 5-Feb-2016 14:35
One person supports this post
Send private message

Buy a cheap and nasty home theatre amp.

 

Cut your losses.

 

 

 

A.

 

 

 

 


4580 posts

Uber Geek
+1 received by user: 2080

Trusted
Subscriber

  Reply # 1485985 5-Feb-2016 15:17
Send private message

On a related note, I got my PC, XBox and BluRay player all connected through the HDMI switch last night after aborting the attempt on Sunday afternoon while the Bluray player's picture was purple and jittery even though the other two were fine. I went off on a tangent trying to find colour-space settings on either the TV or the Bluray player (neither have any accessible, as it happens, other than deep colour on the Bluray player) when it turns out that the answer was as simple as that particular cable (switch comes with 5 in box) was dodgy. Used another one, works fine.

 

Then I set my Denon RC-1024 remote to every set of Philips DVD-player codes it had listed, but none worked so I finally just used learn mode and taught it. All good, now I just needed to teach it the remote codes for the switch, and that's where I was finally defeated. The Denon remote could detect the light from the switch's remote and learn it, but the receiver on the switch wouldn't respond to the light from the Denon remote. :-(

 

And then I found out that my cheap Philips player won't internally decode the HD DTS or Dolby streams and instead insists on sending them out as bitstream. As previously mentioned the receiver pre-dates HD DTS and Dolby, so only decodes them as lossy DTS or Dolby. Still better than DVD-quality but not quite my ultimate goal.

 

Ah well... at least now everything is using HDMI for video *and* audio.





iPad Air + iPhone SE + 2degrees 4tw!

These comments are my own and do not represent the opinions of 2degrees.




Glurp
8205 posts

Uber Geek
+1 received by user: 3780

Subscriber

  Reply # 1500216 26-Feb-2016 22:59
Send private message

After a lot of work, and a fair bit of learning, I have finally come up with an acceptable audio solution for my system. It may not be the best, but so far it works well for me and I am pleased with it.

 

 

 

I started by following a good piece of advice here and I bought a sound card with spdif out. Before that I hooked up an optical output to my motherboard and found some hacked Realtek drivers to force it to do DD 5.1, but this created more problems than it solved and the quality of the audio was poor. After I installed the sound card and found the right driver for it (another saga), I was able to get good quality DD 5.1 audio from a test DVD.

 

 

 

I have a Hauppauge HD recorder with HDMI and spdif audio inputs. My HT Amp only has spdif inputs for digital audio so I can’t use HDMI with it. It still has good sound and I am not prepared to spend hundreds of dollars or more to upgrade it, which I can’t afford anyway. Nor do I see why I should have to. So I have been looking for other ways to get everything to work together. The amp has an spdif monitor output which can be used to feed any digital channel into the Hauppauge and I realised that I could also use it as an spdif switch. All of my devices have either optical or coax digital outputs, including the computer now that I have a sound card, so I plugged all of these into the amp with separate cables and am using HDMI only for video. I have an HDCP stripper in the chain to avoid problems with passing the video through. The only copying I do is from streams for delayed viewing but this avoids hardware issues from the HDCP nonsense.

 

 

 

All of this started because I could not get digital 5.1 channel sound out of the computer. Now I can and everything works well together so I am happy. I only have one remaining question: I cannot find a single free test source of streaming surround sound video on the Internet. There are plenty of downloads but nothing that can be streamed. Also not on YouTube. Everything that says it is 5.1 turns out to be 2-channel stereo in spite of the claims. So can anyone point me to a streaming test video that actually is 5.1 channels? Do I need a particular browser to make this work? I can only find conflicting information about this so am not sure exactly what is required.

 

 

 

 

 

 





I reject your reality and substitute my own. - Adam Savage
 


216 posts

Master Geek
+1 received by user: 35


  Reply # 1500911 28-Feb-2016 19:43
Send private message

Your main problem is that your TV is unlikely to pass multi-channel audio out the optical/spdif output. This is often a licensing issue.

 

Easiest way to fix is get an spdif output on your computer, there are a million and one cheap usb devices that will do this.




Glurp
8205 posts

Uber Geek
+1 received by user: 3780

Subscriber

  Reply # 1500980 28-Feb-2016 21:13
Send private message

Actually my TV turns out to be one of the ones that does, Sony Bravia. But I actually did what you suggest. That is what I wrote in my post just before yours. Everything audio now goes by spdif and that part, at least, of the problem is solved.

 

 





I reject your reality and substitute my own. - Adam Savage
 


1 | 2 
Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.