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Discussion Starter · #1 ·
Hi,


i tryed to search the forum for this but i didn't find a solution or even

pointing to that issue. So if there is an thread for it, please give me a

hint.


I have a ATI 5450 with CAT 10.2 and REALTEK 2.42 istalled. I get bitstreaming

for all audioformats. I only have 60 Hz, but that's another story and i have to

test creating a special monitor driver for my HC5000 projector.


My issue is related to PCM audio. I am using WIN 7 32bit and wanna have

2ch audio out of mediacenter, 5.1 or 7.1 PCM if my blu-ray contains it.


My problem is, that if i configurate my audiodevice to 2 ch all PCM audiotracks

are sent out 2ch. If i switch to 5.1 everything is sent as 5.1 and 7.1 as 7.1.


For music i wanna use an audioselection within my AV-receiver and i can use

it only if there is 2ch audio. For 5.1 PCM and audiodevice to 7.1 my AV-

receiver can't generate the two back channels, because the PC generates

them with silent audio.


What do i have to setup to get 2ch for music from mediacenter, 5.1 or 7.1

from PowerDVD 9 whatever is on the blu-ray ???
 

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Avoid Windows Audio Engine (that fills all the speakers that are not supposed to be used with silent sound) in WASAPI exclusive mode. ReClock and MPC Audio Renderer (replacements of the default DirectSound renderer) as well as a couple of music players (foobar2000, J.River MC) supports WASAPI exclusive mode.
 

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Discussion Starter · #3 ·
so only solution is to use Reclock with WASAPI ?



I only use mediacenter and PowerDVD 9. The problem is if i setup windows

audiodevice not to 5.1 or 7.1 i don't get multichannel PCM out of PowerDVD.



Maybe in mediacenter i can setup a differten speakersetup than in win directly,

but what to setup to let PowerDVD output 8 or 6 channel. Or better PowerDVD

tells me it sends out 6 or 8 channel, but the AV-Receiver gets whatever it

i setup in the audiodevice setup.
 

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PowerDVD 9 Ultra/TMT3 Platinum bitstreams 24 bit/48 kHz (or higher) LPCM so that AVR gets 5.1 from 5.1 track. It sends 16 bit/48 kHz LPCM to Windows Audio Engine so that AVR gets audio streams of whatever channel count you select in Sound control panel. This is very disappointing, but you have to compromise. (I thought PowerDVD supported DPLIIx; doesn't it support it any longer?)


Otherwise using WASAPI exclusive mode (or ASIO for stereo LPCM) is your only choice.
 

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Discussion Starter · #5 ·
hmm, thanks for the fast answer.


So is this always the path ? that PowerDVD bitstreams the PCM audio with

higher bitrate to the windows audio engine and the windows audio engine

sends it out with a lower bitrate to the av-receiver ?


I thought getting a bitstreaming solution will over me bitstreaming also for

PCM audio from blu-ray and in my imagination i thought it would go directly

to the AV-Receiver.


Maybe PowerDVD supports DPLllx but i wanted to let my AV-Receiver do that.

Especially because i wanted to use THX EX mode within the AV-Receiver.
 

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"Bitstreams" here means data streams that OS can't modify. PowerDVD sends 24bit/48kHz or higher LPCM as a special media type (so PowerDVD and ATI audio driver must work togehter) and AVR receives exactly the same audio streams.


LPCM is the standard digital audio format, hence subject to change by Windows Audio Engine. A special care is required if you want to avoid any modification by OS (e.g. bitstreaming or WASAPI exclusive mode). Every compressed audio format (that AVR can decode) does not suffer from this issue: Dolby Digital (Plus), DTS, Dolby TrueHD, DTS-HD.
 

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Discussion Starter · #7 ·
So is it still the fact that PowerDVD downconverts LPCM and that's

the reason why windows audio engine is in between ? I think most

LPCM from Blu-ray should be higher bitrate, or am i wrong ?
 

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No, the latest PowerDVD/TMT itself does not downsample LPCM any longer (with HD 5xxx/Clarkdale).


- 24 bit/48 KHz or higher LPCM tracks: sent over the protected audio path so that OS can't modify it either.

- 16 bit/48 KHz LPCM tracks: sent over the usual audio stream path, hence subject to modification by Windows Audio Engine: AVR gets audio streams at whatever bit depth/sample rate/channel count selected in the Sound control panel, and possibly mixed with other Windows sounds (system sounds, sounds from other players etc.).
 

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Discussion Starter · #9 ·
Ah O.K. thanks. I tested a little more and recognized that my converted

HD-DVDs now as Blu-ray have a 24bit LPCM and they get directly to the

AV-Receiver. And most of my LPCM Blu-rays seem to have only 16bit and

so they way over windows audio engine. O.K. that makes it more clear.


Is there a way to get Reclock to use WASAPI for PCM and let all other

audiotracks ( Dolby TruHD, DTS HD, DTS, DD ) through to be decoded

at the AV-Receiver ?


I tryed Reclock but i can't get Reclock to passthrough these audiotracks,

i get PCM all the time.
 

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ReClock does not support compressed audio bitstreaming; it works only with LPCM (as it has to resample audio streams based on the graphics hardware clock). So you have to enable/disable ReClock based on the audio track (i.e. you have to close the player, then launch it again).


MPC HomeCinema's MPC Audio Renderer supports both compressed audio and LPCM in WASAPI exclusive mode. With ffdshow that supports bitstreaming HD audio bitstreaming, you could have an ideal solution.
(You lose menus, of course.)
 

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Discussion Starter · #11 ·
hmm, not really great ...


So i have to check what the smalles pain is and which way i can

live with.
 
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