[libcamera-devel] [PATCH 1/1] libcamera: controls: Add a control for IQ stability

[David Plowman]

The IqUnstable metadata can be used by IPAs to indicate to an
application that they have not settled sufficiently to produce
reliable image quality. Applications would be advised to avoid using
frames flagged in this way.

One example would be when the camera starts, when the AEC/AGC might
oscillate for a few frames.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
---
 src/libcamera/control_ids.yaml | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/libcamera/control_ids.yaml b/src/libcamera/control_ids.yaml
index f2e542f4..b96e1272 100644
--- a/src/libcamera/control_ids.yaml
+++ b/src/libcamera/control_ids.yaml
@@ -774,6 +774,26 @@ controls:
             Continuous AF is paused. No further state changes or lens movements
             will occur until the AfPauseResume control is sent.
 
+  - IqUnstable:
+      type: bool
+      description: |
+        The value true indicates that the camera algorithms have not settled
+        sufficiently to generate images of reliable quality. The application
+        receiving this frame is advised to drop it and wait for a frame where
+        this metadata reports false (or is absent).
+
+        One example of this would be when the camera system starts. It may be
+        trying to adapt very quickly to the ambient conditions, resulting in a
+        few frames where the image brightness may be subject to unusually
+        extreme oscillations.
+
+        The control may report true at other times, for example when an HDR mode
+        is enabled. Here too there may be a few frames of unpredictable exposure
+        until the algorithms have settled.
+
+        The value false (or absence of the control) indicates that this is a
+        normal frame.
+
   # ----------------------------------------------------------------------------
   # Draft controls section
 
-- 
2.30.2