[mythtv-users] Can mythtv (or mplayer/xine through mythtv) upmix 5.1 sound in 6.1 or 7.1?

[Eric Sharkey]

On Sat, Oct 5, 2013 at 11:14 AM, Marc MERLIN <marc_mtv at merlins.org> wrote:
> On Sat, Oct 05, 2013 at 10:40:46AM -0400, Eric Sharkey wrote:
>> > Digital. Otherwise 5.1 wouldn't work right either :)
>>
>> No, that's not the case.  That's precisely how "Pro Logic" surround
>> sound works.  The audio from multiple channels are downmixed to only 2
>
> You're right. I just never took that seriously. Maybe it works better than
> I know.

It works better than you might think.

As a solution to the problem of "How do I send surround sound
information over broadcast television with an enormous installed base
of stereo/mono receivers encoded in such a way that no additional
bandwidth is used and the existing sets still sound ok but surround
sound sets can get some differentiation between front and back
sounds?" it's quite an ingenious system.  As a solution to "How do I
start from scratch and encode multichannel audio without worrying
about backward compatibility?" it's complete rubbish, of course, but
20+ years ago it was about as good as we could expect to get.

It's really quite amazing to me how the tv signal went from a black
and white mono signal and added color, stereo, surround, closed
captioning, etc. without breaking the ability of older sets to receive
the signal, up to the transition to digital.

> But this puts me back to square 1: I haven't found any alsa config to do
> this, or any other way with mythtv (which I was just told there isn't inside
> mythtv itself).

6.1 configurations just aren't that common.  You're the first person
I've heard of that actually has one.  You may need to code this one up
yourself.

Eric