[v3,2/2] docs: Document SensorSequence request metadata
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Message ID 20260805151819.16382-3-ballen4705@googlemail.com
State New
Headers show
Series
  • libcamera: Add SensorSequence request metadata control
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Commit Message

Bruce Allen Aug. 5, 2026, 3:18 p.m. UTC 
Describe how applications read request metadata and point to
controls::SensorSequence for control-specific details.

Signed-off-by: Bruce Allen <ballen4705@googlemail.com>
---
 Documentation/guides/application-developer.rst | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Patch
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diff --git a/Documentation/guides/application-developer.rst b/Documentation/guides/application-developer.rst
index abc67dd..dff5059 100644
--- a/Documentation/guides/application-developer.rst
+++ b/Documentation/guides/application-developer.rst
@@ -486,6 +486,24 @@  device:
    request->reuse(Request::ReuseBuffers);
    camera->queueRequest(request);
 
+Request metadata
+~~~~~~~~~~~~~~~~
+
+Completed requests also expose metadata as a :doxy-pub:`ControlList` through
+:doxy-pub:`Request::metadata()`. Only controls where
+:doxy-pub:`ControlId::direction()` signals
+:doxy-pub:`ControlId::Direction::Out` are returned as metadata.
+
+Common entries include :doxy-pub:`controls::SensorTimestamp`,
+:doxy-pub:`controls::FrameWallClock`, and :doxy-pub:`controls::SensorSequence`.
+See the documentation of each control for details.
+
+.. code:: cpp
+
+   const ControlList &metadata = request->metadata();
+   if (auto seq = metadata.get(controls::SensorSequence))
+      std::cout << " sensor sequence: " << *seq << std::endl;
+
 Request queueing
 ----------------