core: Add single exposure PiSP HDR mode

Update the --hdr option to support the single exposure multi-frame HDR
mode available on the PiSP HW. The option can now take the following
values:

"off": No HDR
"auto": Automically select the HDR mode, where "sensor" is top priority
"sensor": Sensor HDR (e.g. Camera v3)
"single-exp": Single exposure HDR mode

The implicit value of this argument is "auto".

Signed-off-by: Naushir Patuck <[email protected]>

core/libcamera_app.cpp

@@ -631,6 +631,9 @@ void LibcameraApp::StartCamera()
 		controls_.set(controls::Saturation, options_->saturation);
 	if (!controls_.get(controls::Sharpness))
 		controls_.set(controls::Sharpness, options_->sharpness);
+	if (!controls_.get(controls::HdrMode) &&
+	    (options_->hdr == "auto" || options_->hdr == "single-exp"))
+		controls_.set(controls::HdrMode, controls::HdrModeSingleExposure);
 
 	// AF Controls, where supported and not already set
 	if (!controls_.get(controls::AfMode) && camera_->controls().count(&controls::AfMode) > 0)

core/options.cpp

@@ -146,10 +146,14 @@ bool Options::Parse(int argc, char *argv[])
 	shutter.set(shutter_);
 	flicker_period.set(flicker_period_);
 
-	// HDR control. Set this before opening or listing any cameras.
+	if (hdr != "off" && hdr != "single-exp" && hdr != "sensor" && hdr != "auto")
+		throw std::runtime_error("Invalid HDR option provided: " + hdr);
+
+	// HDR control. Set the sensor control before opening or listing any cameras.
 	// Currently this does not exist in libcamera, so go directly to V4L2
 	// XXX it's not obvious which v4l2-subdev to use for which camera!
 	{
+		bool en = (hdr == "auto" || hdr == "sensor");
 		bool ok = false;
 		for (int i = 0; i < 4 && !ok; i++)
 		{
@@ -159,12 +163,14 @@ bool Options::Parse(int argc, char *argv[])
 			if (fd < 0)
 				continue;
 
-			v4l2_control ctrl { V4L2_CID_WIDE_DYNAMIC_RANGE, hdr };
+			v4l2_control ctrl { V4L2_CID_WIDE_DYNAMIC_RANGE, en };
 			ok = !xioctl(fd, VIDIOC_S_CTRL, &ctrl);
 			close(fd);
 		}
-		if (hdr && !ok)
-			LOG_ERROR("WARNING: Unable to set HDR mode");
+		if (hdr == "sensor" && en && !ok)
+			LOG_ERROR("WARNING: Unable to set sensor HDR mode");
+		else if (hdr == "auto" && en && ok)
+			hdr = "sensor";
 	}
 
 	// We have to pass the tuning file name through an environment variable.
@@ -488,8 +494,7 @@ void Options::Print() const
 				  << afWindow_height << std::endl;
 	if (!lens_position_.empty())
 		std::cerr << "    lens-position: " << lens_position_ << std::endl;
-	if (hdr)
-		std::cerr << "    hdr: enabled" << hdr << std::endl;
+	std::cerr << "    hdr: " << hdr << std::endl;
 	std::cerr << "    mode: " << mode.ToString() << std::endl;
 	std::cerr << "    viewfinder-mode: " << viewfinder_mode.ToString() << std::endl;
 	if (buffer_count > 0)

core/options.hpp

@@ -201,8 +201,10 @@ struct Options
 			"Sets AfMetering to  AfMeteringWindows an set region used, e.g. 0.25,0.25,0.5,0.5")
 			("lens-position", value<std::string>(&lens_position_)->default_value(""),
 			 "Set the lens to a particular focus position, expressed as a reciprocal distance (0 moves the lens to infinity), or \"default\" for the hyperfocal distance")
-			("hdr", value<bool>(&hdr)->default_value(false)->implicit_value(true),
-			 "Enable (1) or disable (0) High Dynamic Range, where supported")
+			("hdr", value<std::string>(&hdr)->default_value("off")->implicit_value("auto"),
+			 "Enable High Dynamic Range, where supported. Available values are \"off\", \"auto\", "
+			 "\"sensor\" for sensor HDR (e.g. for Camera Module 3), "
+			 "\"single-exp\" for PiSP based single exposure multiframe HDR")
 			("metadata", value<std::string>(&metadata),
 			 "Save captured image metadata to a file or \"-\" for stdout")
 			("metadata-format", value<std::string>(&metadata_format)->default_value("json"),
@@ -281,7 +283,7 @@ struct Options
 	bool af_on_capture;
 	std::string metadata;
 	std::string metadata_format;
-	bool hdr;
+	std::string hdr;
 	TimeVal<std::chrono::microseconds> flicker_period;
 	bool no_raw;