[mythtv-users] Digital Audio with myth

[Robert Denier]

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.  Now, as to what the sound card actually supports and what the 
drivers support, I have no idea.  Certainly not being able to control the 
volume from the digital jack is not a new thing.  I suppose the mixer 
controls probably control analog mixers on a sound cards...?  If that is the 
case, then it explains why control of the digital output level is generally 
not found.

From a practical perspective, your better off to pass the unscaled numbers to 
your home theatre receiver.  The reason for this is if say you cut the volume 
to 1/4  (1/(2^2)) of its maximum in amplitude and you are sticking with 16 
bits of precision then you have lost 2 bits of precision.

Of course even hearing the difference between 14 and 16 bits is not that easy, 
and hearing the difference once you move to 24bits may in fact be impossible.

-Robert