[libcamera-devel] [RFC PATCH 4/5] WIP: libcamera: V4L2VideoDevice: Fix a bug in CreateBuffer()

[Hirokazu Honda]

FrameBuffer created in V4L2VideoDevice::CreateBuffer() has the same
number of planes as v4l2 buffer planes. However, if the format is
a single planar format, the number of planes is one. FrameBuffer
should have the same number of planes as color format planes.

Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
---
 src/libcamera/v4l2_videodevice.cpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index ce60dff6..e70076f3 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -1269,7 +1269,6 @@ std::unique_ptr<FrameBuffer> V4L2VideoDevice::createBuffer(unsigned int index)
 
 	const bool multiPlanar = V4L2_TYPE_IS_MULTIPLANAR(buf.type);
 	const unsigned int numPlanes = multiPlanar ? buf.length : 1;
-
 	if (numPlanes == 0 || numPlanes > VIDEO_MAX_PLANES) {
 		LOG(V4L2, Error) << "Invalid number of planes";
 		return nullptr;
@@ -1289,6 +1288,20 @@ std::unique_ptr<FrameBuffer> V4L2VideoDevice::createBuffer(unsigned int index)
 		planes.push_back(std::move(plane));
 	}
 
+
+	V4L2DeviceFormat format{};
+	ret = getFormat(&format);
+	if (ret < 0) {
+		LOG(V4L2, Error) << "Failed to get buffer format";
+		return nullptr;
+	}
+	if (format.fourcc == V4L2_PIX_FMT_NV12) {
+		planes.resize(2);
+		planes[0].length = format.size.width * format.size.height;
+		planes[1].fd = planes[0].fd;
+		planes[1].length = format.size.width * ((format.size.height + 1) / 2);
+	}
+
 	return std::make_unique<FrameBuffer>(std::move(planes));
 }
 
-- 
2.32.0.605.g8dce9f2422-goog