14 Aug
2009
14 Aug
'09
9:04 p.m.
On Fri, Aug 14, 2009 at 05:44:21PM -0400, David Robillard wrote:
Again I would 100% support that, but it is not current practice.
Any application that uses this scheme will be the brave one that
starts a revolution.
Excellent, thanks!
That is also the one I'd support, together with either n3d or n3d
normalisation, but I wish I could share Joern's optimism about it
being accepted...
The matter came up in last year's AMB meeting in Graz. That was
followed by some very hot and mostly useless discussion on the
surround sound list and at various other shady ad-hoc places.
It was scheduled to be discussed again at this year's meeting
in Graz where both Joern and I were present along with the
complete beau monde of Ambisonics, But no conclusion was arrived
at, first because we didn't have enouth time and second because for
many of the participants it was something they were not prepared
for - the necessary introductory talk took almost all the time
we had.
> most favoured normalization scheme is sn3d, i.e.
plugins will have to
> deal with inputs greater than 1.0f.
Not really - for n3d some of the _panning gains_ can be > 1 iff you
set W = 1. Absolute levels are not the same thing as relative gains.
For sn3d the panning gains are <= 1.
but for
political reasons, new plugins should use acn rather than fuma,
so that's what should be defined as a standard first. if there is
sufficient pressure and people are volunteering, another fuma scheme can
always be added.
Sounds good to me. (Fons, what is the situation WRT this stuff with your
ambisonics
plugins? AFAIK they are the only ones that exist in LAD land)
The plugin set (did you get the latest and greatest ?) uses FuMa
and also it assumes that positive azimuth is to the right which is
plain wrong. The only reason for that is that most hosts can't
create a widget that has negative values to the right and positive
ones to the left (and LADSPA can't tell them they should do it).
The plugins will remain what they are, but my support for FuMa ends
there. All new stuff will be n3d or sn3d and use either the 'computer
graphics' (= ACN) or 'Gerzon' order. If the new stuff is more than a
plugin it could *maybe* offer FuMA as an option at the external
interfaces, as e.g. AmbDec does. Internally everything will be n3d.
Anyway, if ports are labeled in 'machine readable' way the order
doesn't matter - a host will be able to sort things out. It does
matter e.g. in a file format that doesn't have metadata to describe
the order.
Dave, don't worry about the weird order of the single character
names shown on the web page about ACN, They are mentioned only
to show how the order relates to the FuMa one. ACN doesn't use
these names, it only uses the numbers.
Another outcome of the Graz meetings is that the port groups
that are currently named H#V# should really be named H#P#.
The H#V# ones do also exist, but are different. I'll have to
rename all existing AmbDec presets for the same reason.
Ciao,
--
FA
Io lo dico sempre: l'Italia รจ troppo stretta e lunga.