From 7ca1371987736e8b3c51818afcbd245ca6286bc0 Mon Sep 17 00:00:00 2001
From: Emilian Peev <epeev@google.com>
Date: Wed, 5 Apr 2017 15:42:22 +0100
Subject: [PATCH] DngCreator: Populate baseline exposure tag

"postRawSensitivityBoost" contains the gain value applied after
RAW. Take this value in to account and populate the baseline
exposure accordingly.

Bug: 33623101
Test: runtest -x
cts/tests/camera/src/android/hardware/camera2/cts/DngCreatorTest.java

Change-Id: Ib90a5c1791c422fd36ec44fb6ef695ba8a1dc475
---
 .../android_hardware_camera2_DngCreator.cpp    | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/core/jni/android_hardware_camera2_DngCreator.cpp b/core/jni/android_hardware_camera2_DngCreator.cpp
index d2932e43fe5bd..3d021d6cc6b25 100644
--- a/core/jni/android_hardware_camera2_DngCreator.cpp
+++ b/core/jni/android_hardware_camera2_DngCreator.cpp
@@ -21,6 +21,7 @@
 #include <algorithm>
 #include <memory>
 #include <vector>
+#include <cmath>
 
 #include <utils/Log.h>
 #include <utils/Errors.h>
@@ -1374,6 +1375,23 @@ static sp<TiffWriter> DngCreator_setup(JNIEnv* env, jobject thiz, uint32_t image
                 TIFF_IFD_0), env, TAG_ISOSPEEDRATINGS, writer);
     }
 
+    {
+        // Baseline exposure
+        camera_metadata_entry entry =
+                results.find(ANDROID_CONTROL_POST_RAW_SENSITIVITY_BOOST);
+        BAIL_IF_EMPTY_RET_NULL_SP(entry, env, TAG_BASELINEEXPOSURE, writer);
+
+        // post RAW gain should be boostValue / 100
+        double postRAWGain = static_cast<double> (entry.data.i32[0]) / 100.f;
+        // Baseline exposure should be in EV units so log2(gain) =
+        // log10(gain)/log10(2)
+        double baselineExposure = std::log(postRAWGain) / std::log(2.0f);
+        int32_t baseExposureSRat[] = { static_cast<int32_t> (baselineExposure * 100),
+                100 };
+        BAIL_IF_INVALID_RET_NULL_SP(writer->addEntry(TAG_BASELINEEXPOSURE, 1,
+                baseExposureSRat, TIFF_IFD_0), env, TAG_BASELINEEXPOSURE, writer);
+    }
+
     {
         // focal length
         camera_metadata_entry entry =