[libcamera-devel] [PATCH v10 4/8] libcamera: video_device: Support passing ColorSpaces to V4L2 video devices

[David Plowman]

The ColorSpace from the StreamConfiguration is now handled
appropriately in the V4L2VideoDevice.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 include/libcamera/internal/v4l2_videodevice.h |  3 ++
 src/libcamera/v4l2_videodevice.cpp            | 32 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
index 9b2ec3af..2d2ccc47 100644
--- a/include/libcamera/internal/v4l2_videodevice.h
+++ b/include/libcamera/internal/v4l2_videodevice.h
@@ -10,6 +10,7 @@
 #include <array>
 #include <atomic>
 #include <memory>
+#include <optional>
 #include <stdint.h>
 #include <string>
 #include <vector>
@@ -21,6 +22,7 @@
 #include <libcamera/base/signal.h>
 #include <libcamera/base/unique_fd.h>
 
+#include <libcamera/color_space.h>
 #include <libcamera/framebuffer.h>
 #include <libcamera/geometry.h>
 #include <libcamera/pixel_format.h>
@@ -167,6 +169,7 @@ public:
 
 	V4L2PixelFormat fourcc;
 	Size size;
+	std::optional<ColorSpace> colorSpace;
 
 	std::array<Plane, 3> planes;
 	unsigned int planesCount = 0;
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index b4b89e27..80a8c8e4 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -383,6 +383,21 @@ bool V4L2BufferCache::Entry::operator==(const FrameBuffer &buffer) const
  * that identifies the image format pixel encoding scheme.
  */
 
+/**
+ * \var V4L2DeviceFormat::colorSpace
+ * \brief The color space of the pixels
+ *
+ * The color space of the image. When setting the format this may be
+ * unset, in which case the driver gets to use its default color space.
+ * After being set, this value should contain the color space that
+ * was actually used. If this value is unset, then the color space chosen
+ * by the driver could not be represented by the ColorSpace class (and
+ * should probably be added).
+ *
+ * It is up to the pipeline handler or application to check if the
+ * resulting color space is acceptable.
+ */
+
 /**
  * \var V4L2DeviceFormat::planes
  * \brief The per-plane memory size information
@@ -871,6 +886,7 @@ int V4L2VideoDevice::getFormatMultiplane(V4L2DeviceFormat *format)
 	format->size.height = pix->height;
 	format->fourcc = V4L2PixelFormat(pix->pixelformat);
 	format->planesCount = pix->num_planes;
+	format->colorSpace = toColorSpace(*pix);
 
 	for (unsigned int i = 0; i < format->planesCount; ++i) {
 		format->planes[i].bpl = pix->plane_fmt[i].bytesperline;
@@ -893,6 +909,12 @@ int V4L2VideoDevice::trySetFormatMultiplane(V4L2DeviceFormat *format, bool set)
 	pix->num_planes = format->planesCount;
 	pix->field = V4L2_FIELD_NONE;
 
+	ret = fromColorSpace(format->colorSpace, *pix);
+	if (ret < 0)
+		LOG(V4L2, Warning)
+			<< "Setting color space unrecognised by V4L2: "
+			<< ColorSpace::toString(format->colorSpace);
+
 	ASSERT(pix->num_planes <= std::size(pix->plane_fmt));
 
 	for (unsigned int i = 0; i < pix->num_planes; ++i) {
@@ -920,6 +942,7 @@ int V4L2VideoDevice::trySetFormatMultiplane(V4L2DeviceFormat *format, bool set)
 		format->planes[i].bpl = pix->plane_fmt[i].bytesperline;
 		format->planes[i].size = pix->plane_fmt[i].sizeimage;
 	}
+	format->colorSpace = toColorSpace(*pix);
 
 	return 0;
 }
@@ -943,6 +966,7 @@ int V4L2VideoDevice::getFormatSingleplane(V4L2DeviceFormat *format)
 	format->planesCount = 1;
 	format->planes[0].bpl = pix->bytesperline;
 	format->planes[0].size = pix->sizeimage;
+	format->colorSpace = toColorSpace(*pix);
 
 	return 0;
 }
@@ -959,6 +983,13 @@ int V4L2VideoDevice::trySetFormatSingleplane(V4L2DeviceFormat *format, bool set)
 	pix->pixelformat = format->fourcc;
 	pix->bytesperline = format->planes[0].bpl;
 	pix->field = V4L2_FIELD_NONE;
+
+	ret = fromColorSpace(format->colorSpace, *pix);
+	if (ret < 0)
+		LOG(V4L2, Warning)
+			<< "Set color space unrecognised by V4L2: "
+			<< ColorSpace::toString(format->colorSpace);
+
 	ret = ioctl(set ? VIDIOC_S_FMT : VIDIOC_TRY_FMT, &v4l2Format);
 	if (ret) {
 		LOG(V4L2, Error)
@@ -977,6 +1008,7 @@ int V4L2VideoDevice::trySetFormatSingleplane(V4L2DeviceFormat *format, bool set)
 	format->planesCount = 1;
 	format->planes[0].bpl = pix->bytesperline;
 	format->planes[0].size = pix->sizeimage;
+	format->colorSpace = toColorSpace(*pix);
 
 	return 0;
 }
-- 
2.30.2