Moritz Barsnick wrote:
On Tue, Nov 11, 2014 at 12:29:09 +0000, Andy Furniss wrote:
Carl Eugen Hoyos wrote:
Where I live all movies are broadcast PLII.
Ahh, I didn't realise it was still so popular.
Where I live - Germany - the "minor" stations try to use less bandwidth
on the satellite transponders / in their bouquets, and transmit only
one AC-3 audio stream with two channels. Nevertheless, I get quite
proper surround sound from my sound system during many movies. So my
conclusion is that they use the PLII "down-mix".
(Unless that statement was a misunderstanding and we're talking about
something totally different.)
As said MythTV contains a PLII decoder (filter).
Doesn't seem very much compared to the quite complicated looking
descriptions of what a "real" decoder supposedly does.
float lt = *samples++;
float rt = *samples++;
bufs->l[ic] = lt;
bufs->lfe[ic] = bufs->c[ic] = (lt+rt) * m3db;
bufs->r[ic] = rt;
// surround channels receive out-of-phase
bufs->ls[ic] = (rt-lt) * 0.5;
bufs->rs[ic] = (lt-rt) * 0.5;
That looks different from what we were looking at earlier in the thread
(and far too simple). Carl Eugen had pointed out this file:
https://github.com/MythTV/mythtv/blob/master/mythtv/libs/libmythfreesurround/el_processor.cpp
Agh, thanks for that - the code I posted is from myth, but obviously I
don't know if it's ever used.
For some reason this thread has split into two for me and I didn't see
the other bit.
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