Track actual pixel/output formats in camera backends

Expose actual_pixel_format and actual_output_format across backends and track the camera-reported formats for UI/telemetry. Aravis: add actual_pixel_format/actual_output_format properties and record _camera_pixel_format when setting pixel format. GenTL: initialize _camera_pixel_format/_actual_output_format, add _output_format_for_frame to infer output format from numpy frames, populate _actual_output_format on read, and record detected camera pixel format in several places. OpenCV: add actual_pixel_format (None) and actual_output_format (BGR8). These changes provide a consistent way to report native and emitted pixel formats to callers.

Author: C-Achard

dlclivegui/cameras/backends/aravis_backend.py

@@ -69,6 +69,16 @@ def actual_fps(self) -> float | None:
         """Return the actual frame rate of the camera after opening."""
         return self._actual_fps
 
+    @property
+    def actual_pixel_format(self) -> str | None:
+        """Camera/native pixel format requested/reported for Aravis."""
+        return self._camera_pixel_format or self._pixel_format
+
+    @property
+    def actual_output_format(self) -> str | None:
+        """Current Aravis backend emits BGR uint8 frames."""
+        return self._actual_output_format or "BGR8"
+
     @classmethod
     def is_available(cls) -> bool:
         """Check if Aravis is available on this system."""
@@ -615,10 +625,12 @@ def _configure_pixel_format(self) -> None:
 
             if self._pixel_format in format_map:
                 self._camera.set_pixel_format(format_map[self._pixel_format])
+                self._camera_pixel_format = self._pixel_format
                 LOG.info(f"Pixel format set to '{self._pixel_format}'")
             else:
                 # Try setting as string
                 self._camera.set_pixel_format_from_string(self._pixel_format)
+                self._camera_pixel_format = self._pixel_format
                 LOG.info(f"Pixel format set to '{self._pixel_format}' (from string)")
         except Exception as e:
             LOG.warning(f"Failed to set pixel format '{self._pixel_format}': {e}")

dlclivegui/cameras/backends/gentl_backend.py

@@ -99,6 +99,9 @@ def __init__(self, settings):
 
         self._pixel_format: str = ns.get("pixel_format") or props.get("pixel_format", "auto")
         self._pixel_format = str(self._pixel_format).strip()
+        self._camera_pixel_format: str | None = None
+        self._actual_output_format: str | None = None
+
         self._rotate: int = int(ns.get("rotate", props.get("rotate", 0))) % 360
         self._crop: tuple[int, int, int, int] | None = self._parse_crop(ns.get("crop", props.get("crop")))
 
@@ -176,6 +179,16 @@ def actual_exposure(self) -> float | None:
     def actual_gain(self) -> float | None:
         return self._actual_gain
 
+    @property
+    def actual_pixel_format(self) -> str | None:
+        """Camera/native pixel format selected on the GenICam PixelFormat node."""
+        return self._camera_pixel_format or (self._pixel_format if self._pixel_format != "auto" else None)
+
+    @property
+    def actual_output_format(self) -> str | None:
+        """Current GenTL backend emits OpenCV-native BGR uint8 frames."""
+        return self._actual_output_format or "BGR8"
+
     @classmethod
     def is_available(cls) -> bool:
         return Harvester is not None
@@ -587,6 +600,21 @@ def waits_for_hardware_trigger(self) -> bool:
         role = str(self._trigger_attr(getattr(self, "_trigger", None), "role", "off") or "off").lower()
         return role in {"external", "follower"}
 
+    @staticmethod
+    def _output_format_for_frame(frame: np.ndarray) -> str:
+        if frame.ndim == 2:
+            if frame.dtype == np.uint8:
+                return "Mono8"
+            return f"Mono{frame.dtype}"
+        if frame.ndim == 3:
+            channels = frame.shape[2]
+            if channels == 3 and frame.dtype == np.uint8:
+                return "BGR8"
+            if channels == 4 and frame.dtype == np.uint8:
+                return "BGRA8"
+            return f"{channels}ch-{frame.dtype}"
+        return str(frame.dtype)
+
     def read(self) -> tuple[np.ndarray, float]:
         if self._acquirer is None:
             raise RuntimeError("GenTL image acquirer not initialised")
@@ -625,6 +653,7 @@ def read(self) -> tuple[np.ndarray, float]:
                 self._read_telemetry(self._acquirer.remote_device.node_map)
             except Exception:
                 pass
+        self._actual_output_format = self._output_format_for_frame(frame)
 
         return frame, timestamp
 
@@ -1312,11 +1341,14 @@ def _configure_pixel_format(self, node_map) -> None:
 
             pixel_format_node.value = selected
             self._pixel_format = str(pixel_format_node.value)
+            self._actual_pixel_format = self._pixel_format
 
             LOG.debug("GenTL pixel format selected: %s", self._pixel_format)
 
         except Exception as e:
             LOG.warning("Failed to configure pixel format '%s': %s", self._pixel_format, e)
+            if self._pixel_format and self._pixel_format.lower() != "auto":
+                self._camera_pixel_format = self._pixel_format
 
     def _configure_trigger(self, node_map) -> None:
         cfg = self._trigger
@@ -1783,7 +1815,13 @@ def _read_telemetry(self, node_map) -> None:
 
             pixel_format = self._node_str(node_map, "PixelFormat")
             if pixel_format is not None:
+                self._camera_pixel_format = pixel_format
                 ns["actual_pixel_format"] = pixel_format
+                ns["detected_pixel_format"] = pixel_format
+
+            output_format = self.actual_output_format
+            if output_format is not None:
+                ns["actual_output_format"] = output_format
 
         except Exception:
             pass

dlclivegui/cameras/backends/opencv_backend.py

@@ -254,6 +254,16 @@ def actual_gain(self) -> None:
         """Not supported by OpenCV backend."""
         return None
 
+    @property
+    def actual_pixel_format(self) -> str | None:
+        """OpenCV does not reliably expose native camera pixel format."""
+        return None
+
+    @property
+    def actual_output_format(self) -> str | None:
+        """OpenCV VideoCapture returns BGR frames in this backend."""
+        return "BGR8"
+
     # ----------------------------
     # Internal helpers
     # ----------------------------