[mythtvnz] Audio on HDMI NVidia Card

[Jean-Yves Avenard]

On 22 October 2012 12:13, Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:
> For a start, I would recommend that you normally use the "plughw"
> devices, rather than "hw".  The "plughw" ones will use all available
> means in ALSA to convert whatever input they are given to a format
> that the corresponding "hw" device will be able to handle.  That means
> for example, if you play a video file with 11025 Hz audio, it will
> work, as it will be converted to 22050 Hz or 44100 Hz which the
> hardware can normally do, or even resampled to 48000 Hz if necessary.

absolutely no need to use plughw with myth, quite the opposite.
myth will perform any conversion required so it can play using much
higher quality resampler than what alsa would use by default.
The up/downmixers used by myth are even better in comparison

Also, when upconverting (or downconverting), it is done using 32 bits
processing.

If you use plughw instead, myth will have no idea on what your
hardware actually support and will let alsa do the job, which won't be
as good.

Back to the orignal problem. You mentioned that you connected your TV
via HDMI? does your TV supports 5.1 audio? most of them are stereo
only.

Otherwise, just go into Setup -> Audio, and try every ALSA device
listed in there. Don't worry about pulse and ignore any of the advice
given above, myth will disable it if it is required.

If you have a recent version of ALSA, it can show you what your TV
supports. When you go through the ALSA devices, if you see the name of
your TV/amp showing at the bottom of the screen: it's the one to use.

(http://www.mythtv.org/wiki/User_Manual:HDAudioPassthrough#Checking_your_TV_.2F_Amplifier_.2F_Audio_Processor_capabilities
for more info)

As far as mixer are concerned, you can't use any mixers but the
software one when using digital audio.

Cheers
JY