[FeiJi Fancier]

I have two PCs, one running Vista HP 32bit and one running Win 7 HP 64bit.

Apart from that, the hardware in these PCs is identical, as is the software I use for playing Blu-Ray disks (TotalMedia Theatre 2), onboard Realtek 7.1 soundcards, LG Blu-Ray/HD-DVD players.

My problem is that the Vista PC has no problem using the optical SPDIF output to deliver DD5.1 on Blu-Ray disks to my Logitech Z-5400 Amp & speaker set.

But the Windows 7 PC cannot. My amp for this system is a Creative Azur 540R V2. The PC can deliver DD5.1 from every other source, but if it is downmixing from True-HD all I get is two channel PCM, and there doesn't seem to be anything I can do about it.

Am I missing something obvious, is there some switch I've missed. Or is this a traint of Windows 7? Have MS inhibited the output in some way.

Both PCs have ATI Radeon HD3650 graphics cards, but I ignore the audio output on those because none of my hi-fi kit has HDMI inputs.

There is one slight difference, and that is that the Win7 PC also has onboard graphics and audio via HDMI, but again that is ignored.

I'm very computer literate, incidentally (a Novell administrator & PC support technician), so like to think I know what I'm doing.

[FeiJi Fancier]

As a stopgap, until I can afford an HDMI 1.3 capable AV Amp, will I get decoded true-hd/DD5.1 via the 3 two channel analogue outputs of the motherboard's sound card? Or would that even be a superior solution?

In fact, my Azur can support 6.1 via analogue, but I don't have a rear speaker.

[jameson_uk]

With the machines being on different OS (not to mention the fact one is 32bit and one is 64bit) they are quite different.

Are you saying that the Win7 machine will happily output a DD bitstream with everything apart from BD? Only I am assuming that a disc that works on the Vista machine is not working on the Win7 machine?

If that is the case then it has to do be down to the player. I would go through the settings in TMT2 and check they are identical. That said I thought only TMT3 was Win7 compatible anyway?

[Hambox]

Not sure if this is related but it sounds like I have experienced a similar issue. I use MakeMKV to archive my blurays and KMPlayer/CoreAVC/Haali to play. On Windows Vista 32bit this worked great and DTS/DD were output over SPDIF via the HDMI cable to my Onkyo receiver. I upgraded to Windows 7 Ultimate 32bit over the weekend and just coult not get DTS/DD to my receiver. As I got so frustrated I decided to try and use an optical cable and separate the audio from the HDMI so output SPDIF over optical. This worked and we were able to watch out film with a nice DD soundtrack...

I later wanted to watch something on Sky HD so had to switch back the optical cable and then reconfigured my HTPC to use SPDIF via the HDMI port again. When I tried to play DD/DTS again it miraculously jumped in to life and I am now able to use SPDIF to get DD/DTS over HDMI.

No idea why this worked but it seems Windows 7 needed me to show it the way

[FeiJi Fancier]

Originally Posted by jameson_uk

With the machines being on different OS (not to mention the fact one is 32bit and one is 64bit) they are quite different.

Are you saying that the Win7 machine will happily output a DD bitstream with everything apart from BD? Only I am assuming that a disc that works on the Vista machine is not working on the Win7 machine?

If that is the case then it has to do be down to the player. I would go through the settings in TMT2 and check they are identical. That said I thought only TMT3 was Win7 compatible anyway?

Yes, you are correct, the Win7 machine will output a DD bitstream via optical SPDIF with everything apart from BD but more specifically, BDs with True-HD and no native DD5.1.

None of my BD disks that have Dolby True-HD will downmix to DD5.1 via optical on my Win7 PC - so it's not just one disk.

Those same disks play perfectly well on the Vista PC.

I will check with ARCsoft as to whether TMT2 is compatible and if it is how it should be setup to play these disks properly. But I'm sure it is compatible, I'm sure it was working under Win7 64bit Ultimate pre-release candidate. I did a clean Win7 64bit HP install recently, to make it permanently legal.

@Hambox - neither of my AV amps support HDMI.

[FeiJi Fancier]

I think I've found the source of my problem. I can't fix it, though, but maybe someone out there knows the answer.

In the Setup menu for TMT2, under the "Audio" tab there are a two visible tick boxes, and one which is greyed out.

I have the Audio Output Mode set to S/PDIF. The three tickboxes are labeled:

"Remember Audio Volume" (visible and changeable - but not set, and doesn't seem to matter one way or the other)

"Enable down sample rate (192KHZ)" (visible, changeable and set)

and the third one is

"Enable Audio Mixer" (greyed out - unalterable).

The "Advanced" button is also greyed out, but that changes if I change the Audio Output Mode to any of the speaker output settings - ie 5.1, 7.1, etc..

Does anyone know how to change the status of the "Enable Audio Mixer", as I believe this is what I need to enable DD5.1 downmixing? Remember this is Win7, using the Realtek HD onboard soundcard. DD5.1 works fine, so long as it doesn't require downmixing from True-HD.

Thanks.

Edit: Additional. Bought Terminator Salvation today, and this has no problems at all. This Blu-Ray movie has dts-HD Master Audio, which successfully downmixes to 5.1. Curiouser and Curiouser.

The mixer option remains greyed out.

[MikeK]

DTS-HD-MA has a standard DTS core - any DTS capable player can play this without any mixing (or rather transcoding).

In the case of TrueHD, many Blurays have a standard AC3 track hidden within the TrueHD track - as above, this track should be playable by any AC3 capable player.
Some others have a standard selectable AC3/DTS track!

However, there are some Blurays which have neither a hidden AC3 track within the TrueHD, nor any sepearte AC3/DTS standard (selectable) track.
In these cases, the player has to downmix to PCM2.0 if SPDIF is set as the output UNLESS said player has the ability to transcode the TrueHD track to either AC3 or DTS, which can then be sent over SPDIF.


AFAIK, TMT2 should be able to perform this transcoding - and it's setup by the "Enable Audio Mixer" button - as you said. No idea why it should be greyed out though.
Are you trying this with nothing playing?
Is TMT up to date patch-wise?

The only other thing which springs to mind, is whether the audio transcoding part of TMT2 simply doesn't work under Win7 - I don't know whether that's the case though!

[FeiJi Fancier]

Originally Posted by MikeK

AFAIK, TMT2 should be able to perform this transcoding - and it's setup by the "Enable Audio Mixer" button - as you said. No idea why it should be greyed out though.
Are you trying this with nothing playing?
Is TMT up to date patch-wise?

The only other thing which springs to mind, is whether the audio transcoding part of TMT2 simply doesn't work under Win7 - I don't know whether that's the case though!

You can't access setup unless you are playing something! It is up to date patch-wise too.

Win7 True-HD->DD5.1 downmixing compatability? Well, I guess that's what I'm trying to discern. None of my True-HD BD disks play DD5.1 any longer on this computer, yet they do on my Vista HTPC, and the Audio Mixer option is accessible.

Its one of those nagging problems that simply leave me trying to scratch the itch as it were. I can't get at the root cause and think that I'm only going to be able to fix this if I get either a stand alone Blu-Ray player, upgrade my receiver, or try using three dual channel analogue connections.

The problem with the final option is that I need the sockets it to provide an input to the computer so that I can record from my turntable and cassette recorder (I have a number of tapes of a band I recorded (with permission) myself direct from a mixing desk).

Edit: You can enter setup if you're not playing anything, and guess what - I was able to set the audio mixer too.

Now to test it!

[FeiJi Fancier]

Sorted - thanks to MikeK

Just to clarify what I did to make Total Media Theatre perform True-HD->DD5.1 downmixing. Well, it doesn't show as Dolby Digital 5.1 on my receiver, it simply shows as 5.1 - I'm guessing from what I've read, and witnessed on my receiver, it is actually DTS Digital 5.1 - which is much the same, or even better.

Remove any disks from your Blu-Ray player.

Start Total Media Theatre.

Click on the small "spanner" icon. This brings up the Setup window.

Click on the Audio tab at the top.

You will now see that the "Enable Audio Mixer" checkbox is visible and changeable. Simple populate it with a tick, by clicking on it.

Click on the Ok button, then close Total Media Theatre in the normal way.

Then load up your favourite movie which wouldn't work before and "Hey Presto" glorious 5.1 audio during the movie (playback equipment dependant, of course).

Thanks Mike.