Re: Can't get 5.1 Dolby Digital out of S/PDIF

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From: Derek R. Flickinger (DrFlick_at_online.InteractiveHomesInc.com)
Date: 04/10/04 

Date: Sat, 10 Apr 2004 14:30:25 -0400

I am sorry, I probably should have been a little more specific (and I am
sure Robert will be kind enough to keep me honest here). MCE requires that
the non-BDA DirectShow Filters with Stream Class Video Capture Drivers from
the DirectX 9 interfaces for the TV Tuner and TV Audio filters have to be
seen as a single entity when feeding the Crossbar Filter, which then feeds
the rest of the mux and compression components (as seen in GraphEdit) into
the Stream Buffer Engine. I know of no way to change the pin configurations
to support the routing of an "external" audio source into this chain.

  =D-

"Derek R. Flickinger" <DrFlick@online.InteractiveHomesInc.com> wrote in
message news:%23d8ddkWHEHA.3476@TK2MSFTNGP11.phx.gbl...
> That does not work. The audio <i>must</i> go through the Stream Buffer
> Engine along with the video to keep them in synch (or at least as close as
> it gets). Even running it into the optical in on something like the
> Audigy 2 and through the PC does not work right because that audio does
> not follow the trick play functionality either (because it is not going
> through the Stream Buffer Engine). Even with all of that, we usually
> still have to put about an 80 mS delay on the audio via the receiver
> itself to have it synch up correctly (one of the features of something
> like the AVR series in the Harman Kardon line or using one of the better
> audio/video switchers). We have found that forcing the external receiver
> into one of its Dolby modes works the best all around for this
> configuration and seems to get the best all-around surround sound
> experience across all sources.
>
> =D-
>
> "R. J. Salvi" <rjsalvi@nospamambianceacoustics.com> wrote in message
> news:MQ3dc.43971$Lq4.8759@twister.socal.rr.com...
>> Derek,
>>
>> Assuming your A/V receiver has more than one optical input, why not just
>> run
>> the STB digital out to one of the receiver's digital inputs? The video
>> will
>> still be accessed through the PC and the STB controlled with the MCE
>> remote.
>> It may require switching inputs on the receiver whenever you're watching
>> TV,
>> but you'll be certain to have 5.1 when braodcast as such.
>>
>> I know, I know...the challenge of having it work the way it's supposed to
>> is
>> too overwhelming to not address. :-)
>>
>> You know...one more thing crosses my mind. What sound card/on-board chip
>> do
>> you have? Does it have its own control panel? You might check and see if
>> its
>> control panel has a menu for digital I/O and set it to lock on the input
>> signal. hth.
>>
>> --
>> Robert J. Salvi, Ambiance Acoustics
>> http://www.ambianceacoustics.com
>> San Diego, CA USA
>> (858) 485-7514
>>
>> "Derek R. Flickinger" <DrFlick@online.InteractiveHomesInc.com> wrote in
>> message news:eoJqTOMHEHA.3776@tk2msftngp13.phx.gbl...
>>> Robert,
>>>
>>> Good point. Since we rarely actually use the internal tuners and
>> front-end
>>> the machines with a set top box into the S-Video in, I neglected to
>>> define
>>> the environment (I forgot that most installations discussed here are
>>> using
>>> the PC-based tuners). We actually run the audio from the set top into
>>> the
>>> audio in on the tuner card (you can't put it into the audio card in the
>>> machine directly or the trick play features have no control over the
>>> audio
>>> signal). Since the set top does "transmit" the audio with Dolby
>>> capabilities, MCE <i>appears to</i> pass this thru in this
>>> configuration.
>>> The problem seems to exhibit itself, as you say, when the external
>>> amp/receiver tries to "latch onto" the audio signals from certain
>>> channels
>>> and it seems to get really confused on how to encode it with it's own
>>> DSP-based surround audio.
>>>
>>> The way I read it, his DVD played did work correctly, so it seems like
>>> it
>> is
>>> more a problem with MCE and the internal tuner than it is with the DVD
>>> player itself. Either way, sorry for the confusion - I need to be a
>> little
>>> more cognizant of the specific configuration and define that before
>>> replying. As a side note, we would love to be able to use the optical
>> audio
>>> out from the STB into the "tuner" instead of the analog signal.
>>> Hopefully
>>> this will be taken into consideration as MCE moves to supporting a more
>>> versatile set of inputs from a wider variety of digital sources.
>>>
>>> =D-
>>>
>>> "R. J. Salvi" <rjsalvi@nospamambianceacoustics.com> wrote in message
>>> news:whTcc.43813$Lq4.39294@twister.socal.rr.com...
>>> > Hi Derek,
>>> >
>>> > Correct me if I'm wrong, but when listening to TV, I believe all
>>> > analog
>> TV
>>> > tuners are only capable of 2-channel stereo. It would explain why
>>> > "they
>>> > seem
>>> > to play in some weird left/right/front/back unbalanced audio
>>> > mode"...the
>>> > receiver is trying to decode a stereo only input for a surround mode.
>>> >
>>> > In response to the original posters query...I don't know, but it
>>> > sounds
>>> > like
>>> > a software problem. He might consider uninstalling and subsequently
>>> > reinstalling his DVD program.
>>> >
>>> > --
>>> > Robert J. Salvi, Ambiance Acoustics
>>> > http://www.ambianceacoustics.com
>>> > San Diego, CA USA
>>> > (858) 485-7514
>>> >
>>> > "Derek R. Flickinger" <DrFlick@online.InteractiveHomesInc.com> wrote
>>> > in
>>> > message news:u3XSL5$GEHA.2664@TK2MSFTNGP11.phx.gbl...
>>> >> We are curious just how you define "can't get." Are you saying that
>> your
>>> >> indicators on your preamp/amp/receiver are not showing it via its
>>> >> audio
>>> > auto
>>> >> detection features or that you simply cannot hear it (it only comes
>>> >> out
>>> >> of
>>> >> the front speakers)? We have noticed on a few installations that
>> certain
>>> >> receivers do not seem to detect it properly, but you definitely can
>> hear
>>> > it
>>> >> in true surround sound. We also have noticed that certain MCE
>>> >> sources
>>> > seem
>>> >> to get detected okay but do not play in "surround sound mode"
>>> >> properly
>>> >> (especially with certain TV channels). In fact, they seem to play in
>>> >> some
>>> >> weird left/right/front/back unbalanced audio mode. I believe all of
>> our
>>> >> setups are using one of the versions of Creative's Audigy 2
>>> >> interfaces.
>>> > It
>>> >> is almost as if we need to put a "digital audio stream" analyzer on
>>> >> the
>>> > link
>>> >> to see if the "audio type" information is being stripped out by MCE
>>> >> for
>>> > some
>>> >> reason so the amp does see it. In the situations where we have
>>> > experienced
>>> >> problems, always forcing the receiver to one of its Dolby settings
>> seems
>>> > to
>>> >> allow it to play well across all of MCE's sources and you can't tell
>>> >> it
>>> >> isn't playing it "properly" unless you actually look at the
>>> >> indicators
>> on
>>> >> the face of the receiver (the machines only use the MCE interface).
>>> >> As
>>> > for
>>> >> a more technical solution, we still are investigating....
>>> >>
>>> >> Regards.
>>> >>
>>> >> =D-
>>> >>
>>> >> Derek R. Flickinger
>>> >> Interactive Homes, Inc.
>>> >>
>>> >> "Larry Li" <lli@austin.rr.com> wrote in message
>>> >> news:MuGbc.36923$o_.6041@fe1.texas.rr.com...
>>> >> >I can't get 5.1 Dolby Digital out of my new FMC-901 under Media
>> Center.
>>> > I
>>> >> > tried to run InterVideo DVD player application standalone, and it
>>> >> > put
>>> > out
>>> >> > 5.1 Dolby Digital just fine. Anyone know what could be wrong?
>>> >> >
>>> >> > I am using S/PDIF out.
>>> >> >
>>> >> > -Larry
>>> >> >
>>> >> >
>>> >>
>>> >>
>>> >
>>> >
>>>
>>>
>>
>>
>
>

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