[libcamera-devel] [PATCH v6 1/1] gstreamer: Provide multiple colorimetry support for libcamerasrc

[Rishikesh Donadkar]

Iterate over each GValue in the colorimetry list,
retrieve the colorimetry string, convert to colorspace,
set the colorspace in the  stream_cfg and validate the camera configuration.
Retrieve the colorspace after validation, convert to colorimetry and
check if it is same as the colorimetry requested.

If none of the colorimetry requested is supported by the camera (i.e. not
the same after validation) then set the stream_cfg to the previous
configuration that was present before trying new colorimetry.

Signed-off-by: Rishikesh Donadkar <rishikeshdonadkar at gmail.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
---
 src/gstreamer/gstlibcamera-utils.cpp | 49 +++++++++++++++++++++++-----
 src/gstreamer/gstlibcamera-utils.h   |  4 ++-
 src/gstreamer/gstlibcamerasrc.cpp    |  2 +-
 3 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp
index 244a4a79..f73b6349 100644
--- a/src/gstreamer/gstlibcamera-utils.cpp
+++ b/src/gstreamer/gstlibcamera-utils.cpp
@@ -316,9 +316,9 @@ gst_libcamera_stream_configuration_to_caps(const StreamConfiguration &stream_cfg
 	return caps;
 }
 
-void
-gst_libcamera_configure_stream_from_caps(StreamConfiguration &stream_cfg,
-					 GstCaps *caps)
+void gst_libcamera_configure_stream_from_caps(std::unique_ptr<CameraConfiguration> &cam_cfg,
+					      StreamConfiguration &stream_cfg,
+					      GstCaps *caps)
 {
 	GstVideoFormat gst_format = pixel_format_to_gst_format(stream_cfg.pixelFormat);
 	guint i;
@@ -395,15 +395,46 @@ gst_libcamera_configure_stream_from_caps(StreamConfiguration &stream_cfg,
 	stream_cfg.size.width = width;
 	stream_cfg.size.height = height;
 
-	/* Configure colorimetry */
-	if (gst_structure_has_field(s, "colorimetry")) {
-		const gchar *colorimetry_str = gst_structure_get_string(s, "colorimetry");
-		GstVideoColorimetry colorimetry;
+	const GValue *colorimetry_ = gst_structure_get_value(s, "colorimetry");
+	if (!colorimetry_)
+		return;
 
-		if (!gst_video_colorimetry_from_string(&colorimetry, colorimetry_str))
-			g_critical("Invalid colorimetry %s", colorimetry_str);
+	/* Configure Colorimetry */
+	GstVideoColorimetry colorimetry;
+	if (GST_VALUE_HOLDS_LIST(colorimetry_)) {
+		StreamConfiguration pristine_stream_cfg = stream_cfg;
+		for (i = 0; i < gst_value_list_get_size(colorimetry_); i++) {
+			const GValue *val = gst_value_list_get_value(colorimetry_, i);
+
+			if (!gst_video_colorimetry_from_string(&colorimetry, g_value_get_string(val))) {
+				g_warning("Invalid colorimetry %s, trying next option", g_value_get_string(val));
+				continue;
+			}
+
+			std::optional<ColorSpace> clrSpace = colorspace_from_colorimetry(colorimetry);
+			stream_cfg.colorSpace = clrSpace;
+
+			/* Validate the configuration and check if the requested
+			 * colorimetry can be applied to the sensor. Otherwise,
+			 * restore the configuration back to pristine one.
+			 */
+			if (cam_cfg->validate() != CameraConfiguration::Invalid) {
+				/* Check the colorspace returned after validation, with the colorspace before validation */
+				if (stream_cfg.colorSpace == clrSpace) {
+					g_print("Selected colorimetry %s\n", gst_video_colorimetry_to_string(&colorimetry));
+					break;
+				} else {
+					stream_cfg = pristine_stream_cfg;
+				}
+			}
+		}
+	} else if (G_VALUE_HOLDS_STRING(colorimetry_)) {
+		if (!gst_video_colorimetry_from_string(&colorimetry, g_value_get_string(colorimetry_)))
+			g_critical("Invalid colorimetry %s", g_value_get_string(colorimetry_));
 
 		stream_cfg.colorSpace = colorspace_from_colorimetry(colorimetry);
+	} else {
+		GST_WARNING("colorimetry field type should only be string or list.");
 	}
 }
 
diff --git a/src/gstreamer/gstlibcamera-utils.h b/src/gstreamer/gstlibcamera-utils.h
index 164189a2..7afad576 100644
--- a/src/gstreamer/gstlibcamera-utils.h
+++ b/src/gstreamer/gstlibcamera-utils.h
@@ -8,6 +8,7 @@
 
 #pragma once
 
+#include <libcamera/camera.h>
 #include <libcamera/camera_manager.h>
 #include <libcamera/stream.h>
 
@@ -16,7 +17,8 @@
 
 GstCaps *gst_libcamera_stream_formats_to_caps(const libcamera::StreamFormats &formats);
 GstCaps *gst_libcamera_stream_configuration_to_caps(const libcamera::StreamConfiguration &stream_cfg);
-void gst_libcamera_configure_stream_from_caps(libcamera::StreamConfiguration &stream_cfg,
+void gst_libcamera_configure_stream_from_caps(std::unique_ptr<libcamera::CameraConfiguration> &cam_cfg,
+					      libcamera::StreamConfiguration &stream_cfg,
 					      GstCaps *caps);
 #if !GST_CHECK_VERSION(1, 17, 1)
 gboolean gst_task_resume(GstTask *task);
diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index 16d70fea..25059914 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -503,7 +503,7 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
 
 		/* Fixate caps and configure the stream. */
 		caps = gst_caps_make_writable(caps);
-		gst_libcamera_configure_stream_from_caps(stream_cfg, caps);
+		gst_libcamera_configure_stream_from_caps(state->config_, stream_cfg, caps);
 	}
 
 	if (flow_ret != GST_FLOW_OK)
-- 
2.25.1