Add experimental gain map support

CMakePresets.json

@@ -43,6 +43,7 @@
         "WITH_OpenJPEG_ENCODER_PLUGIN" : "OFF",
         "WITH_FFMPEG_DECODER" : "ON",
         "WITH_FFMPEG_DECODER_PLUGIN" : "OFF",
+        "WITH_EXPERIMENTAL_GAIN_MAP" : "OFF",
 
         "WITH_REDUCED_VISIBILITY" : "OFF",
         "WITH_DEFLATE_HEADER_COMPRESSION" : "ON",
@@ -88,6 +89,7 @@
         "WITH_OpenJPEG_ENCODER_PLUGIN" : "ON",
         "WITH_FFMPEG_DECODER" : "ON",
         "WITH_FFMPEG_DECODER_PLUGIN" : "ON",
+        "WITH_EXPERIMENTAL_GAIN_MAP" : "OFF",
 
         "WITH_REDUCED_VISIBILITY" : "ON",
         "WITH_DEFLATE_HEADER_COMPRESSION" : "ON",
@@ -120,6 +122,7 @@
         "WITH_OpenJPEG_DECODER" : "OFF",
         "WITH_OpenJPEG_ENCODER" : "OFF",
         "WITH_FFMPEG_DECODER" : "OFF",
+        "WITH_EXPERIMENTAL_GAIN_MAP" : "OFF",
 
         "WITH_REDUCED_VISIBILITY" : "ON",
         "WITH_DEFLATE_HEADER_COMPRESSION" : "OFF",

examples/heif_enc.cc

@@ -53,6 +53,9 @@
 #include "benchmark.h"
 #include "libheif/exif.h"
 #include "common.h"
+#if WITH_EXPERIMENTAL_GAIN_MAP
+#include "libheif/heif_gain_map.h"
+#endif
 
 int master_alpha = 1;
 int thumb_alpha = 1;
@@ -724,10 +727,18 @@ int main(int argc, char** argv)
   struct heif_error error;
 
   std::shared_ptr<heif_image> primary_image;
+  struct heif_image_handle* handle;
 
   for (; optind < argc; optind++) {
     std::string input_filename = argv[optind];
 
+#if WITH_EXPERIMENTAL_GAIN_MAP
+    bool is_gain_map = false;
+    if (input_filename.find("gain_map") != std::string::npos) {
+      is_gain_map = true;
+    }
+#endif
+
     if (output_filename.empty()) {
       std::string filename_without_suffix;
       std::string::size_type dot_position = input_filename.find_last_of('.');
@@ -865,12 +876,28 @@ int main(int argc, char** argv)
     }
 
 
-    struct heif_image_handle* handle;
     error = heif_context_encode_image(context.get(),
                                       image.get(),
                                       encoder,
                                       options,
                                       &handle);
+
+#if WITH_EXPERIMENTAL_GAIN_MAP
+    if (is_gain_map) {
+      struct heif_image_handle* gain_map_image_handle;
+      heif_gain_map_metadata gmm;
+
+      error = heif_context_encode_gain_map_image(context.get(),
+                                                 image.get(),
+                                                 handle,
+                                                 encoder,
+                                                 nullptr,
+                                                 &gmm,
+                                                 &gain_map_image_handle);
+      heif_image_handle_release(gain_map_image_handle);
+    }
+#endif
+
     if (error.code != 0) {
       heif_encoding_options_free(options);
       std::cerr << "Could not encode HEIF/AVIF file: " << error.message << "\n";

examples/heif_info.cc

@@ -48,6 +48,9 @@
 #include <assert.h>
 #include <stdio.h>
 #include "common.h"
+#if WITH_EXPERIMENTAL_GAIN_MAP
+#include "libheif/heif_gain_map.h"
+#endif
 
 
 /*
@@ -687,6 +690,23 @@ int main(int argc, char** argv)
       }
     }
 
+#if WITH_EXPERIMENTAL_GAIN_MAP
+  // gain map pixels
+  heif_image_handle* gain_map_image_handle;
+  heif_image* gain_map_image;
+  err = heif_context_get_gain_map_image_handle(ctx.get(), &gain_map_image_handle);
+  if (err.code != heif_error_Ok) {
+    goto __exit;
+  }
+  heif_decode_image(gain_map_image_handle, &gain_map_image, heif_colorspace_undefined, heif_chroma_undefined, nullptr);
+
+  // gain map metadata
+  heif_gain_map_metadata gmm;
+  heif_image_get_gain_map_metadata(ctx.get(), &gmm);
+  gmm.dump();
+__exit:
+#endif
+
     heif_image_release(image);
 
     heif_image_handle_release(handle);

libheif/CMakeLists.txt

@@ -150,6 +150,13 @@ if (WITH_UNCOMPRESSED_CODEC)
             uncompressed_image.cc)
 endif ()
 
+if (WITH_EXPERIMENTAL_GAIN_MAP)
+    target_compile_definitions(heif PUBLIC WITH_EXPERIMENTAL_GAIN_MAP=1)
+    target_sources(heif PRIVATE
+            heif_gain_map.h
+            heif_gain_map.cc)
+endif ()
+
 write_basic_package_version_file(${PROJECT_NAME}-config-version.cmake COMPATIBILITY ExactVersion)
 
 install(TARGETS heif EXPORT ${PROJECT_NAME}-config

libheif/box.cc

@@ -2018,6 +2018,30 @@ Error Box_mdcv::write(StreamWriter& writer) const
   return Error::Ok;
 }
 
+#if WITH_EXPERIMENTAL_GAIN_MAP
+void Box_altr::add_item_id(heif_item_id id) {
+  m_item_IDs.push_back(id);
+}
+
+Error Box_altr::write(StreamWriter& writer) const
+{
+  size_t box_start = reserve_box_header_space(writer);
+
+  writer.write32(1);                             // unsigned int(32) group_id;
+  writer.write32((uint32_t) m_item_IDs.size());  // unsigned int(32) num_entities_in_group;
+  for (uint32_t i = 0; i < m_item_IDs.size(); i++) {
+    writer.write32((uint32_t) m_item_IDs[i]);    // unsigned int(32) entity_id;
+  }
+  prepend_header(writer, box_start);
+
+  return Error::Ok;
+}
+
+Error Box_altr::parse(BitstreamRange& range)
+{
+  return range.get_error();
+}
+#endif
 
 Error Box_ipco::get_properties_for_item_ID(uint32_t itemID,
                                            const std::shared_ptr<class Box_ipma>& ipma,

libheif/box.h

@@ -455,6 +455,10 @@ class Box_infe : public FullBox
 
   const std::string& get_item_type() const { return m_item_type; }
 
+#if WITH_EXPERIMENTAL_GAIN_MAP
+  const std::string& get_item_name() const { return m_item_name; }
+#endif
+
   void set_item_type(const std::string& type) { m_item_type = type; }
 
   void set_item_name(const std::string& name) { m_item_name = name; }
@@ -812,6 +816,13 @@ class Box_idat : public Box
 class Box_grpl : public Box
 {
 public:
+#if WITH_EXPERIMENTAL_GAIN_MAP
+  Box_grpl()
+  {
+    set_short_type(fourcc("grpl"));
+  }
+#endif
+
   std::string dump(Indent&) const override;
 
 protected:
@@ -965,6 +976,26 @@ class Box_mdcv : public Box
   Error parse(BitstreamRange& range) override;
 };
 
+#if WITH_EXPERIMENTAL_GAIN_MAP
+class Box_altr : public Box
+{
+public:
+  Box_altr()
+  {
+    set_short_type(fourcc("altr"));
+  }
+
+  void add_item_id(heif_item_id id);
+
+  Error write(StreamWriter& writer) const override;
+
+protected:
+  Error parse(BitstreamRange& range) override;
+
+private:
+  std::vector<heif_item_id> m_item_IDs;
+};
+#endif
 
 /**
  * User Description property.