From 137dbf3eb19b84a9ad7fb0b4e2ec14b19ab6f1f5 Mon Sep 17 00:00:00 2001
From: Lawrence Lee <45837045+Lawrence37@users.noreply.github.com>
Date: Fri, 16 Aug 2024 21:57:37 -0700
Subject: [PATCH] Support black level of Sony ILME-FX3 with dcraw

Read the black level from the second SR2SubIFD BlackLevel tag.
---
 rtengine/dcraw.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/rtengine/dcraw.cc b/rtengine/dcraw.cc
index 5626482fe..e495a6105 100644
--- a/rtengine/dcraw.cc
+++ b/rtengine/dcraw.cc
@@ -6733,6 +6733,13 @@ int CLASS parse_tiff_ifd (int base)
       case 29443:
 	FORC4 cam_mul[c ^ (c < 2)] = get2();
 	break;
+      case 29456: // Adapted from LibRaw: Sony SR2SubIFD BlackLevel
+	FORC4 cblack[c ^ (c >> 1) /*RGGB_2_RGBG(c)*/] = get2();
+	i = cblack[3];
+	FORC3 if (i > (int)cblack[c]) i = cblack[c];
+	FORC4 cblack[c] -= i;
+	black = i;
+	break;
       case 29459:
 	FORC4 cam_mul[c] = get2();
 	i = (cam_mul[1] == 1024 && cam_mul[2] == 1024) << 1;