From 9b7fa136e8949fed466608e623995b5038d60f8a Mon Sep 17 00:00:00 2001
From: Brad Werth <bwerth@mozilla.com>
Date: Fri, 22 Apr 2022 22:10:19 +0000
Subject: [PATCH] Bug 1764618 Part 3: Make macOS hardware decode respect
 transfer functions. r=media-playback-reviewers,alwu

Differential Revision: https://phabricator.services.mozilla.com/D143839
---
 dom/media/platforms/apple/AppleVTDecoder.cpp | 13 ++++++++++---
 dom/media/platforms/apple/AppleVTDecoder.h   |  1 +
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/dom/media/platforms/apple/AppleVTDecoder.cpp b/dom/media/platforms/apple/AppleVTDecoder.cpp
index ef1fe9ee6803..11de03b3230e 100644
--- a/dom/media/platforms/apple/AppleVTDecoder.cpp
+++ b/dom/media/platforms/apple/AppleVTDecoder.cpp
@@ -44,6 +44,8 @@ AppleVTDecoder::AppleVTDecoder(const VideoInfo& aConfig,
       mColorSpace(aConfig.mColorSpace
                       ? *aConfig.mColorSpace
                       : DefaultColorSpace({mPictureWidth, mPictureHeight})),
+      mTransferFunction(aConfig.mTransferFunction ? *aConfig.mTransferFunction
+                                                  : gfx::TransferFunction::PQ),
       mColorRange(aConfig.mColorRange),
       mColorDepth(aConfig.mColorDepth),
       mStreamType(MP4Decoder::IsH264(aConfig.mMimeType)  ? StreamType::H264
@@ -430,6 +432,8 @@ void AppleVTDecoder::OutputFrame(CVPixelBufferRef aImage,
   } else {
 #if !defined(MAC_OS_VERSION_10_13) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_VERSION_10_13
+    CFStringRef kCVImageBufferTransferFunction_ITU_R_2100_HLG =
+        CFSTR("ITU_R_2100_HLG");
     CFStringRef kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ =
         CFSTR("SMPTE_ST_2084_PQ");
 #endif
@@ -459,9 +463,12 @@ void AppleVTDecoder::OutputFrame(CVPixelBufferRef aImage,
       CVBufferSetAttachment(aImage, kCVImageBufferColorPrimariesKey,
                             kCVImageBufferColorPrimaries_ITU_R_2020,
                             kCVAttachmentMode_ShouldPropagate);
-      CVBufferSetAttachment(aImage, kCVImageBufferTransferFunctionKey,
-                            kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ,
-                            kCVAttachmentMode_ShouldPropagate);
+      CVBufferSetAttachment(
+          aImage, kCVImageBufferTransferFunctionKey,
+          (mTransferFunction == gfx::TransferFunction::HLG)
+              ? kCVImageBufferTransferFunction_ITU_R_2100_HLG
+              : kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ,
+          kCVAttachmentMode_ShouldPropagate);
     }
 
     CFTypeRefPtr<IOSurfaceRef> surface =
diff --git a/dom/media/platforms/apple/AppleVTDecoder.h b/dom/media/platforms/apple/AppleVTDecoder.h
index 167d28c6ff8a..1bfc0e9300d1 100644
--- a/dom/media/platforms/apple/AppleVTDecoder.h
+++ b/dom/media/platforms/apple/AppleVTDecoder.h
@@ -91,6 +91,7 @@ class AppleVTDecoder : public MediaDataDecoder,
   const uint32_t mDisplayWidth;
   const uint32_t mDisplayHeight;
   const gfx::YUVColorSpace mColorSpace;
+  const gfx::TransferFunction mTransferFunction;
   const gfx::ColorRange mColorRange;
   const gfx::ColorDepth mColorDepth;
 
-- 
2.11.4.GIT