Re: Questions about new hardware & Debian (or Linux in general)
On Tue, Nov 12, 2013 at 10:15:03PM -0600, Stan Hoeppner wrote:
> On 11/12/2013 7:11 PM, Doug wrote:
> > On 11/12/2013 07:32 PM, Stan Hoeppner wrote:
> >> On 11/12/2013 5:37 PM, Jon N wrote:
> >> ...
> >>> There is one an area that I'm pretty unsure of. I am planning on
> >>> purchasing a Nvidia video card and disabling the built in Intel video
> >>> support. Since I plan to use this computer as a MythTV
> >>> frontend/backend (as well as for general web browsing/email) getting
> >>> the audio out on the Nvidia card's HDMI port is important to my
> >>> particular setup. So will the audio automatically be switched to the
> >>> Nvidia cards HDMI connector?
> >> No, it won't be automatic. And frankly I don't believe nVidia supports
> >> HDMI digital audio pass through, nor any discrete GPU card. For
> >> argument's sake, let's say it does. Then you run into the problem that
> >> the onboard audio chip can't pass digital audio through PCIe to the
> >> nVidia HDMI port. None of them are designed to do this, that I'm
> >> aware of.
> >>
> >> If I were you I'd get a mainboard with with HDMI out and use the CPU's
> >> GPU. Mobos that have onboard HDMI have their audio chips wired to the
> >> HDMI port, the chips support PCM/AC3 digital output, and selecting the
> >> HDMI output for digital audio is pretty straightforward.
> >>
> >> The Intel GPU should be plenty powerful enough for HD1080 output. If
> >> you decide it's not, and want to add a discrete card, you'll need a mobo
> >> with coaxial digital SPDIF output, or Toslink optical digital output,
> >> and a TV or A/V receiver that is cable of using an HDMI input for video
> >> while using coax or Toslink for audio. Nearly all modern A/V receivers
> >> support this. WRT LCD/Plasma TVs I have no idea how many support this.
> >>
> > I have an NVidia GeForce GTX 550 Ti card in a machine with on-board
> > Realtek 662 sound
> > decoder. Normally--that is locally--sound is decoded by the Realtek on
> > the mobo.
> > The NVidia card has a mini HDMI connector (I needed an adapter to
> > standard)
> > and the card has a sound decoder in it.
>
> This isn't the case. All digital audio (AC3, PCM, DTS, etc) is decoded
> at the endpoint device. In this case that is the TV or A/V receiver.
> Everywhere else in the path the digital audio stream is simply passed
> through.
>
> The trick with Linux is getting all of the devices recognized, and being
> able to select which 'path' the digital stream should take.
>
> > Using Windows XP, I could run a
> > movie thru HDMI
> > to my TV set and picture and sound would come thru perfectly. NVidia
> > provides a driver
> > for Windows that makes this "just work."
>
> And this is the key. nVidia registers an audio output device that can
> be selected in control panel as the preferred output device. WSS then
> directs digital audio through this device. There is no such equivalent
> in Linux, that I'm aware of.
>
ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html
There you go; now you can be aware of it.
3.1 Pre-Azalia:
Some older GPUs included a connector to receive S/PDIF audio
from a separate sound card, and route that audio over HDMI. This
document does not cover such devices at all.
3.2. Azalia:
Newer GPUs include a fully-fledged sound card, implemented
according to the Intel HD-audio ("Azalia”) specification. This
document covers such devices.
-dsr-
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