[libcamera-devel] [PATCH v1 3/5] gstreamer:Install the colorimetry property

[Rishikesh Donadkar]

> What would be a use case though for forcing a specific colorimetry ? Do the V4L2
> stack we have supports this ?
>
> > +     g_object_class_install_property(object_class,PROP_COLORIMETRY,spec2);
> >  }

a use case would be to set a colorspace requested by user with something like
g_object_set(source, "colorimetry", "bt2020", NULL);
I have tested that the requested colorimetry gets applied to the
camera if it passes the validation.



On Mon, Jul 4, 2022 at 11:43 PM Nicolas Dufresne
<nicolas.dufresne at collabora.com> wrote:
>
> Le dimanche 03 juillet 2022 à 13:03 +0530, Rishikesh Donadkar a écrit :
> > Add the colorimetry field in the _GstLibcameraSrc. Add switch cases in
> > gst_libcamera_src_set_property() and gst_libcamera_src_get_property() to
> > access and modify the property.
> >
> > Signed-off-by: Rishikesh Donadkar <rishikeshdonadkar at gmail.com>
> > ---
> >  src/gstreamer/gstlibcamerasrc.cpp | 18 +++++++++++++++++-
> >  1 file changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > index 46fd02d2..120319b3 100644
> > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > @@ -121,6 +121,7 @@ struct _GstLibcameraSrc {
> >       GstTask *task;
> >
> >       gchar *camera_name;
> > +     gchar *colorimetry;
> >
> >       GstLibcameraSrcState *state;
> >       GstLibcameraAllocator *allocator;
> > @@ -129,7 +130,8 @@ struct _GstLibcameraSrc {
> >
> >  enum {
> >       PROP_0,
> > -     PROP_CAMERA_NAME
> > +     PROP_CAMERA_NAME,
> > +     PROP_COLORIMETRY,
> >  };
> >
> >  G_DEFINE_TYPE_WITH_CODE(GstLibcameraSrc, gst_libcamera_src, GST_TYPE_ELEMENT,
> > @@ -532,6 +534,10 @@ gst_libcamera_src_set_property(GObject *object, guint prop_id,
> >               g_free(self->camera_name);
> >               self->camera_name = g_value_dup_string(value);
> >               break;
> > +     case PROP_COLORIMETRY:
> > +             g_free(self->colorimetry);
> > +             self->colorimetry = g_value_dup_string(value);
> > +             break;
> >       default:
> >               G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
> >               break;
> > @@ -549,6 +555,9 @@ gst_libcamera_src_get_property(GObject *object, guint prop_id, GValue *value,
> >       case PROP_CAMERA_NAME:
> >               g_value_set_string(value, self->camera_name);
> >               break;
> > +     case PROP_COLORIMETRY:
> > +             g_value_set_string(value, self->colorimetry);
> > +             break;
> >       default:
> >               G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
> >               break;
> > @@ -717,4 +726,11 @@ gst_libcamera_src_class_init(GstLibcameraSrcClass *klass)
> >                                                            | G_PARAM_READWRITE
> >                                                            | G_PARAM_STATIC_STRINGS));
> >       g_object_class_install_property(object_class, PROP_CAMERA_NAME, spec);
> > +
> > +     GParamSpec *spec2 = g_param_spec_string("colorimetry", "Coloirmetry",
> > +                                             "Colorimetry that will be applied to the StreamConfiguration", nullptr,
> > +                                            (GParamFlags)(GST_PARAM_MUTABLE_READY
> > +                                                          | G_PARAM_READWRITE
> > +                                                          | G_PARAM_STATIC_STRINGS));
>
> As this is a field in caps, the appropriate way to interact in userland is to
> place such feild in downstream caps filter. Properties are not acceptable.
>
>   libcamerasrc ! video/x-raw,colorimetry=bt709 ! ...
>
> What would be a use case though for forcing a specific colorimetry ? Do the V4L2
> stack we have supports this ?
>
> > +     g_object_class_install_property(object_class,PROP_COLORIMETRY,spec2);
> >  }
>