[PATCH v1] gstreamer: Use `Control<>` objects when setting controls

Barnabás Pőcze barnabas.pocze at ideasonboard.com
Fri Mar 28 17:07:36 CET 2025


`g_value_get_boolean()` returns `gboolean`, which is actually `int`. Thus

  // ControlValue x;
  auto val = g_value_get_boolean(...);
  x.set(val);

will cause `ControlValue::set<int, ...>(const int&)` to be called, which
will save the value as `ControlTypeInteger32`, not `ControlTypeBoolean`.

Then, if something tries to retrieve the boolean value, it will run into an
assertion failure:

  Assertion `type_ == details::control_type<std::remove_cv_t<T>>::value' failed.

in `ControlValue::set()`.

Fix this by using the appropriately typed `Control<>` object when setting
the value in the `ControlList` as this ensures that the value will be
converted to the actual type of the control.

Bug: https://bugs.libcamera.org/show_bug.cgi?id=261
Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
---
There is a simpler fix to this issue as well:

	diff --git a/src/gstreamer/gstlibcamera-controls.cpp.in b/src/gstreamer/gstlibcamera-controls.cpp.in
	index d937b19e6..8378b5fd0 100644
	--- a/src/gstreamer/gstlibcamera-controls.cpp.in
	+++ b/src/gstreamer/gstlibcamera-controls.cpp.in
	@@ -271,7 +271,7 @@ bool GstCameraControls::setProperty(guint propId, const GValue *value,
			}
			Rectangle val = value_get_rectangle(value);
	{%- else %}
	-               auto val = g_value_get_{{ ctrl.gtype }}(value);
	+               {{ ctrl.element_type }} val = g_value_get_{{ ctrl.gtype }}(value);
	{%- endif %}
			control.set(val);
	{%- endif %}

---
 src/gstreamer/gstlibcamera-controls.cpp.in | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/src/gstreamer/gstlibcamera-controls.cpp.in b/src/gstreamer/gstlibcamera-controls.cpp.in
index d937b19e6..89c530da0 100644
--- a/src/gstreamer/gstlibcamera-controls.cpp.in
+++ b/src/gstreamer/gstlibcamera-controls.cpp.in
@@ -223,7 +223,6 @@ bool GstCameraControls::setProperty(guint propId, const GValue *value,
 {%- for ctrl in ctrls %}

 	case controls::{{ ctrl.namespace }}{{ ctrl.name|snake_case|upper }}: {
-		ControlValue control;
 {%- if ctrl.is_array %}
 		size_t size = gst_value_array_get_size(value);
 {%- if ctrl.size != 0 %}
@@ -254,12 +253,9 @@ bool GstCameraControls::setProperty(guint propId, const GValue *value,
 		}

 {%- if ctrl.size == 0 %}
-		control.set(Span<const {{ ctrl.element_type }}>(values.data(),
-								size));
+		Span<const {{ ctrl.element_type }}> val(values.data(), size);
 {%- else %}
-		control.set(Span<const {{ ctrl.element_type }},
-			         {{ ctrl.size }}>(values.data(),
-						  {{ ctrl.size }}));
+		Span<const {{ ctrl.element_type }}, {{ ctrl.size }}> val(values.data(), size);
 {%- endif %}
 {%- else %}
 {%- if ctrl.is_rectangle %}
@@ -273,10 +269,9 @@ bool GstCameraControls::setProperty(guint propId, const GValue *value,
 {%- else %}
 		auto val = g_value_get_{{ ctrl.gtype }}(value);
 {%- endif %}
-		control.set(val);
 {%- endif %}
-		controls_.set(propId, control);
-		controls_acc_.set(propId, control);
+		controls_.set(controls::{{ ctrl.namespace }}{{ ctrl.name }}, val);
+		controls_acc_.set(controls::{{ ctrl.namespace }}{{ ctrl.name }}, val);
 		return true;
 	}
 {%- endfor %}
--
2.49.0


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