[FFmpeg-devel] [PATCH] avfilter: add hrtfm filter

[Aurelien Jacobs]

On Mon, Mar 19, 2018 at 10:49:28PM -0800, Lou Logan wrote:
> On Fri, Mar 16, 2018, at 11:44 AM, Paul B Mahol wrote:
> > Signed-off-by: Paul B Mahol <onemda at gmail.com>
> > ---
> >  doc/filters.texi         |  60 ++++++
> >  libavfilter/Makefile     |   1 +
> >  libavfilter/af_hrtfm.c   | 486
> >  +++++++++++++++++++++++++++++++++++++++++++++++>  libavfilter/allfilters.c |   1 +
> >  4 files changed, 548 insertions(+)
> >  create mode 100644 libavfilter/af_hrtfm.c
> >
> > diff --git a/doc/filters.texi b/doc/filters.texi
> > index bd43a7ac6e..c298054325 100644
> > --- a/doc/filters.texi
> > +++ b/doc/filters.texi
> > @@ -3218,6 +3218,66 @@ Change highpass width.
> >  Syntax for the command is : "@var{width}"
> >  @end table
> > 
> > + at section hrtfm
> > +
> > +Apply simple Head Related Transfer Function Model to audio stream.
> > +
> > +hrtfm filter creates virtual loudspeakers around the user for
> > binaural> +listening via headphones (audio formats up to 9 channels supported).> +
> > +This is very simple implementation which does not use any HRIRs.
> > +
> > +It accepts the following parameters:
> > +
> > + at table @option
> > + at item hradius
> 
> You didn’t like the head_radius option name suggestion?
> 
> > +Set head radius of listener. In meters. Default value is
> > @code{0.0891}.
> Why meters instead of cm? 

Because if you want to specify centimeters, you can use the option
like this: -hradius 8.91c
The only way for SI prefix to make sense is to have the options
expressed in the base unit.
So I think hradius should be expressed in meters and every new options
should always be expressed in their base unit.