[mythtv-users] Digital Audio with myth

[Robert Denier]

On Monday 28 November 2005 04:56 pm, Steve Hodge wrote:
> On 11/29/05, Robert Denier <rdenier at finiteinfinity.org> wrote:
> > On Monday 28 November 2005 02:08 pm, Nick wrote:
> > > On 25/11/05, Phill Edwards <philledwards at gmail.com> wrote:
> >
> > [snip]
> >
> > > That's because the S/PDIF is outputting a digital stream which the
> > > receiver decodes and is responsible for amplifying. I don't think it's
> > > possible to dynamically adjust a digital audio stream before it hits
> > > the amp.
> >
> > It is always possible to scale numbers and a digital stream is just a
> > stream of numbers.
>
> But there isn't necessarily a direct mapping between the numbers in
> the stream and the volume of the resulting audio. Think AC3 and DTS
> passthrough.

A quick glance shows that the PCM control _does_ control the audio level of a 
CMI9761 when using mplayer to play a realaudio stream, but it doesn't seem to 
work in Myth.  Perhaps there is the beginning of a solution there or maybe I 
just need to set something.

Obviously, as was stated above, this may be useless if the stream has some 
complex encoding and is just being "passed through", but it seems as if it 
should be at least possible to control the volume level in myth if the audio 
being decoding is just 2 channel stereo PCM audio compressed as mpeg3.

-Robert