[RFC PATCH 1/6] libcamera: framebuffer: Add FrameMetadata::Status::FrameStartup

[Naushir Patuck]

Add a new status enum, FrameStartup, used to denote that even though
the frame has been successfully captured, the IQ parameters set by the
IPA will cause the frame to be unusable and applications are advised to
not consume this frame. An example of this would be on a cold-start of
the 3A algorithms, and there will be large oscillations to converge to
a stable state quickly.

Additional, update the definition of the FrameError state to include its
usage when the sensor is known to produce a number of invalid/error
frames after stream-on.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
---
 include/libcamera/framebuffer.h |  1 +
 src/libcamera/framebuffer.cpp   | 11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/libcamera/framebuffer.h b/include/libcamera/framebuffer.h
index ff83924300ac..e83825b466aa 100644
--- a/include/libcamera/framebuffer.h
+++ b/include/libcamera/framebuffer.h
@@ -26,6 +26,7 @@ struct FrameMetadata {
 		FrameSuccess,
 		FrameError,
 		FrameCancelled,
+		FrameStartup,
 	};
 
 	struct Plane {
diff --git a/src/libcamera/framebuffer.cpp b/src/libcamera/framebuffer.cpp
index 826848f75a56..36e56d593bc3 100644
--- a/src/libcamera/framebuffer.cpp
+++ b/src/libcamera/framebuffer.cpp
@@ -44,11 +44,18 @@ LOG_DEFINE_CATEGORY(Buffer)
  * of the FrameMetadata structure are valid.
  * \var FrameMetadata::FrameError
  * An error occurred during capture of the frame. The frame data may be partly
- * or fully invalid. The sequence and timestamp fields of the FrameMetadata
- * structure is valid, the other fields may be invalid.
+ * or fully invalid. This status may also indicate an invalid frame produced by
+ * the sensor during its startup or restart phase. The sequence and timestamp
+ * fields of the FrameMetadata structure is valid, the other fields may be
+ * invalid.
  * \var FrameMetadata::FrameCancelled
  * Capture stopped before the frame completed. The frame data is not valid. All
  * fields of the FrameMetadata structure but the status field are invalid.
+ * \var FrameMetadata::FrameStartup The frame has been successfully captured.
+ * However, the IPA is in a cold-start or reset phase and will result in image
+ * quality parameters producing unusable images. Applications are recommended to
+ * not consume these frames. All fields of the FrameMetadata structure are
+ * valid.
  */
 
 /**
-- 
2.43.0