[PATCH v2] gstreamer: Fix critical warning "gst_value_set_int_range_step: assertion 'start < end' failed"

[Hou Qi]

This changes is fixing critical error message
"gst_value_set_int_range_step: assertion 'start < end' failed" observed
when building GStreamer caps from a stream configuration whose size
range holds a single size.

GStreamer range step definition requires distinct min and max values
definitions, otherwise above error message is output.

libcamera SizeRange instance may return a single size leading to
identical min and max values. Add a conditional check where the min and
max of the range are distinct during iterating the supported sizes for
each pixelformat.

Signed-off-by: Hou Qi <qi.hou at nxp.com>
---
 src/gstreamer/gstlibcamera-utils.cpp | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp
index ec4da435..79f71246 100644
--- a/src/gstreamer/gstlibcamera-utils.cpp
+++ b/src/gstreamer/gstlibcamera-utils.cpp
@@ -359,13 +359,21 @@ gst_libcamera_stream_formats_to_caps(const StreamFormats &formats)
 			GValue val = G_VALUE_INIT;
 
 			g_value_init(&val, GST_TYPE_INT_RANGE);
-			gst_value_set_int_range_step(&val, range.min.width, range.max.width, range.hStep);
-			gst_structure_set_value(s, "width", &val);
-			gst_value_set_int_range_step(&val, range.min.height, range.max.height, range.vStep);
-			gst_structure_set_value(s, "height", &val);
+			if (range.min.width == range.max.width) {
+				gst_structure_set(s, "width", G_TYPE_INT, range.min.width, nullptr);
+			} else {
+				gst_value_set_int_range_step(&val, range.min.width, range.max.width, range.hStep);
+				gst_structure_set_value(s, "width", &val);
+			}
+			if (range.min.height == range.max.height) {
+				gst_structure_set(s, "height", G_TYPE_INT, range.min.height, nullptr);
+			} else {
+				gst_value_set_int_range_step(&val, range.min.height, range.max.height, range.vStep);
+				gst_structure_set_value(s, "height", &val);
+			}
 			g_value_unset(&val);
 
-			gst_caps_append_structure(caps, s);
+			caps = gst_caps_merge_structure(caps, s);
 		}
 	}
 
-- 
2.34.1