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-   -   How to Get Dolby Digital (http://www.avsforum.com/forum/26-home-theater-computers/1608866-how-get-dolby-digital.html)

jasguild 07-18-2014 10:41 PM

How to Get Dolby Digital
 
I have an asus M4A88TD-VEVO/USB3 htpc. it supposedly had a realtek hd audio chipset. I am connecting to it my Denon 1910 receiver via HDMI and optical

I was hoping to pass through DD to my receiver but instead only get PLII and other analog. I have tried audio connections through HDMI and optical but still doesn't show up as DD on the receiver.

Am I missing something?

renethx 07-19-2014 01:17 AM

The player must send undecoded DD instead of decoding it to multichannel LPCM.

pittsoccer33 07-19-2014 03:50 AM

1 Attachment(s)
what player are you using?

under control panel --> sound --> playback devices you should see your receiver. Mine is old and doesn't have HDMI, so im using toslink. did you check off these boxes? that's the first step. whatever player you are using will likely need to be set up too.


http://www.avsforum.com/forum/attach...2&d=1405766953

jasguild 07-20-2014 06:53 PM

I am using windows media player and windows media center in Windows 7 using 32 bits. Under play back devices I see the realtek HDMI device but it only lists 2 channel and no other options for Dolby or DTS

renethx 07-20-2014 09:06 PM

WMPlayer uses Microsoft DTV-DVD Audio Decoder by default, that always decodes AC3 to 5.1 PCM. If this is the case, you have to use another audio decoder.

jasguild 07-21-2014 07:41 AM

Hmmmm

I have another HTPC that has a Turtle Bay sound card with DDL. On that computer, the DDL card starts sending dolby digital computer as soon as I log into windows even before I open/choose WMP. So I am curious as to why the decoder in WMP would be relevant in this HTPC?

In either case, where would I get another decoder? Is it an addon or plugin for WMP?

Thank you

Foxbat121 07-21-2014 08:08 AM

Quote:

Originally Posted by jasguild (Post 25916633)
Hmmmm

I have another HTPC that has a Turtle Bay sound card with DDL. On that computer, the DDL card starts sending dolby digital computer as soon as I log into windows even before I open/choose WMP. So I am curious as to why the decoder in WMP would be relevant in this HTPC?

In either case, where would I get another decoder? Is it an addon or plugin for WMP?

Thank you

DDL, or Dolby Digital Live, is a real time encoder that encodes multi-channel PCM into DD 5.1. Such component is no longer needed in modern HDMI days as re-encoding into DD 5.1 add additional audio quality loss and HDMI can already carry multi-channel PCM without the need to encode into DD 5.1.

Your problem is that your current playback software seems to be only sending out decoded PCM audio, not bitstreaming the original audio assume they are already DD 5.1. Remember, without DDL hardware, you won't see DD 5.1 if your source material doesn't have it. And a lot of playback software defaults to decoding instead of bitstreaming.

jasguild 07-21-2014 08:14 AM

Quote:

Originally Posted by Foxbat121 (Post 25917497)
DDL, or Dolby Digital Live, is a real time encoder that encodes multi-channel PCM into DD 5.1. Such component is no longer needed in modern HDMI days as re-encoding into DD 5.1 add additional audio quality loss and HDMI can already carry multi-channel PCM without the need to encode into DD 5.1.

Your problem is that your current playback software seems to be only sending out decoded PCM audio, not bitstreaming the original audio assume they are already DD 5.1. Remember, without DDL hardware, you won't see DD 5.1 if your source material doesn't have it. And a lot of playback software defaults to decoding instead of bitstreaming.

When you say "re-encoding into DD 5.1" is that the equivalent of Dolby Pro Logic II?

"Without DDL hardware, you won't see DD 5.1 if your source material doesn't have it" Are you saying then that unless I am playing a say a movie through my HTPC (which has DD), I cant get pure dolby? I am assuming the Reaktek on board sound card does not have DDL. what can I get from this card?

Foxbat121 07-21-2014 08:30 AM

Quote:

Originally Posted by jasguild (Post 25917641)
When you say "re-encoding into DD 5.1" is that the equivalent of Dolby Pro Logic II?

No. DDL takes multi-channel PCM audio source and use a DD lossy algorithm to compress them into DD 5.1 audio stream in real time. Since it is a lossy compression, everytime you do it, you lost some audio quality. If your receiver can already handle HDMI audio, there is no need for this kind of conversion. But how many channels of audio you will receive, it is totally up to the audio source and application you are using.

Quote:

Originally Posted by jasguild (Post 25917641)
"Without DDL hardware, you won't see DD 5.1 if your source material doesn't have it" Are you saying then that unless I am playing a say a movie through my HTPC (which has DD), I cant get pure dolby? I am assuming the Reaktek on board sound card does not have DDL. what can I get from this card?

Correct. If you want everything to be DD 5.1, you need DDL either via dedicated hardware or software (some fashions of DDL software was available on some on-board sound chips but that was very limited availability and probably no longer available because of the lack of interest since moving to HDMI).

jasguild 07-21-2014 08:45 AM

Quote:

Originally Posted by Foxbat121 (Post 25918201)
No. DDL takes multi-channel PCM audio source and use a DD lossy algorithm to compress them into DD 5.1 audio stream in real time. Since it is a lossy compression, everytime you do it, you lost some audio quality. If your receiver can already handle HDMI audio, there is no need for this kind of conversion. But how many channels of audio you will receive, it is totally up to the audio source and application you are using.



Correct. If you want everything to be DD 5.1, you need DDL either via dedicated hardware or software (some fashions of DDL software was available on some on-board sound chips but that was very limited availability and probably no longer available because of the lack of interest since moving to HDMI).

Very interesting. On my other computer with the DDL card, the sound to me is a lot more crisp and complete when I select DDL instead of PCM (even for sources that are not DD compliant). For eg I listen to a lot of mp3 music and having the HTPC send the signal as DD 5.1 sounds night and day better than just PCM. When I select PCM my receiver can only receive it using Pro Logic and several other formats that are not pure Dolby or DTS but with the DDL enabled my receiver receives everything as DD 5.1

So from my limited experience, it behooves me as to why anyone would not want DD 5.1 on EVERY source. Am I missing something else?

thanks again

Foxbat121 07-21-2014 09:15 AM

Sounds like to me it is your receiver to blame or the way how it is connected. Is it an HDMI receiver or you just using optical or coax cable for audio connection? There is also a long debate about PCM vs bitstreaming, but more to do with lossless encodes like Dolby TrueHD and DTS-HD MA, than the lossy compression like DD.

jasguild 07-21-2014 09:28 AM

Quote:

Originally Posted by Foxbat121 (Post 25919537)
Sounds like to me it is your receiver to blame or the way how it is connected. Is it an HDMI receiver or you just using optical or coax cable for audio connection? There is also a long debate about PCM vs bitstreaming, but more to do with lossless encodes like Dolby TrueHD and DTS-HD MA, than the lossy compression like DD.

On that computer, I am connecting via Optical from the DDL sound card to the receiver but in the DDL driver, I can manually enable the DDL function or just choose PCM. What annoys me with this appraoch is the DDL card will not simultaneously output to analog when DDL is in use. SO if I want to get analog signals to my Zone 2 I have to manually switch from DDL to PCM.

Ideally what I am trying to accomplish from my HTPC that we are discussing, is to get HD audio (lossless audio) from my Realtek HD audio card to my receiver via HDMI for EVERY source AND secondly be able to simultaneously produce an analog equivalent. Is that asking for too much? :)

Andy_Steb 07-21-2014 09:39 AM

Realtek HD audio card and your HDMI are two completely different things. Your HDMI needs the AMD HD audio drivers which is installed with AMD Catalyst.

HDMI and simultaneously produce an analog equivalent: Yes, you're asking for too much. (although it sure would be nice)

Foxbat121 07-21-2014 10:59 AM

Quote:

Originally Posted by jasguild (Post 25919897)
Ideally what I am trying to accomplish from my HTPC that we are discussing, is to get HD audio (lossless audio) from my Realtek HD audio card to my receiver via HDMI for EVERY source AND secondly be able to simultaneously produce an analog equivalent. Is that asking for too much? :)

I'm not familiar with analog simultaneous output with HDMI. For your setup, all you need is just HDMI connection to the receiver. Then configure your playback software to either output PCM or bitstream. You have to make sure the formats you want to send out via HDMI shows up in the HDMI digital audio device, not Realtek chip (which is analog only). You will typically find such audio device named after your receiver or TV if you use HDMI.

There are different processing on the receiver based on source audio formats. For example, Dolby ProLogic II is typically engaged automatically when a 2-ch source is detected. DPL II is used to convert 2-ch audio to 5.1 or more channels. There are a few sub-modes in DPL II processing depending on your receiver. For example, on my Pioneer receiver, I can choose between DPL IIx Music or DPL IIx Movie etc. If you don't like DPL II processing, you should be able to turn it off which should produce almost the same audio output as your DD without the addition quality loss of DD conversion.

renethx 07-21-2014 11:08 AM

Quote:

Originally Posted by jasguild (Post 25916633)
Hmmmm

I have another HTPC that has a Turtle Bay sound card with DDL. On that computer, the DDL card starts sending dolby digital computer as soon as I log into windows even before I open/choose WMP. So I am curious as to why the decoder in WMP would be relevant in this HTPC?

In either case, where would I get another decoder? Is it an addon or plugin for WMP?

Thank you

DDL (or DTS Connect) encodes all audio streams coming into the sound card to DD (or DTS). You will have to use a sound card supporting DDL (or DTS Connect), of course. Most of onboard audio don't support it and none of audio controller in graphics supports it. So the audio decoder of the player must bitstream DD/DTS.

Controlling WMP is fairly complicated, there is no way to control video/audio codecs via WMP UI, you always have to hack the registry if you want to change something. For example, for some media files, WMP uses Media Foundation (MF) and there is no user control unless you disable MF. For some files it uses DirectShow (DS) and Windows preferred decoders / merit values. If you are willing to learn the basics and configure it yourself, the following are all you need:

- Codec Tweak Tool (a registry hacking tool)
- LAV Filters (a set of DS source/splitter filter, video filer and audio filter)
- xy-VSFilter (a DS subtitle filter)
- GraphStudioNext (a DS filter management utility)

Basic procedure is

1. Disable MF if you want to play a video format for which MS wants to use MF, e.g. mp4 (Codec Tweak Tool).
2. Make sure to use LAV Source/Splitter and LAV Video Filter for the video formats/codecs you want to play (Codec Tweak Tool).
3. Make sure AC3 and DTS bitstreaming is selected in LAV Audio Decoder configuration.
4. Raise the merit value of DirectVobSub (auto-loading version), e.g., to 0x00800006 (otherwise it won't be loaded even when it should be) (GraphStudioNext).

Shark007 codec pack is perhaps easier, the effect is the same though. Or just use another player such as MPC-HC / MPC-BE with LAV Filters (a piece of cake). Even the internal audio decoder can encode multichannel LPCM to AC3 on the fly (e.g. if you play multichannel AAC, you can get surround sound over S/PDIF or 880G's HDMI).


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