add support for configuring min/max content boost

The min/max content boost for different encoding presets are computed
internally basing on the input hdr and sdr intents. This change
introduces an API to configure the values from the app side. If the
library during its computations observes a small min-max range, then
client recommendation is ignored. Otherwise, the configured values are
selected.

fixes google#160

Test: ./ultrahdr_app <options> -k 0.01 -K 8.0

examples/ultrahdr_app.cpp

@@ -23,6 +23,7 @@
 #include <string.h>
 
 #include <algorithm>
+#include <cfloat>
 #include <cmath>
 #include <cstdint>
 #include <fstream>
@@ -257,7 +258,8 @@ class UltraHdrAppInput {
                    uhdr_img_fmt_t oFmt = UHDR_IMG_FMT_32bppRGBA1010102, bool isHdrCrFull = false,
                    int gainmapScaleFactor = 4, int gainmapQuality = 85,
                    bool enableMultiChannelGainMap = false, float gamma = 1.0f,
-                   bool enableGLES = false, uhdr_enc_preset_t encPreset = UHDR_USAGE_REALTIME)
+                   bool enableGLES = false, uhdr_enc_preset_t encPreset = UHDR_USAGE_REALTIME,
+                   float minContentBoost = FLT_MIN, float maxContentBoost = FLT_MAX)
       : mHdrIntentRawFile(hdrIntentRawFile),
         mSdrIntentRawFile(sdrIntentRawFile),
         mSdrIntentCompressedFile(sdrIntentCompressedFile),
@@ -283,6 +285,8 @@ class UltraHdrAppInput {
         mGamma(gamma),
         mEnableGLES(enableGLES),
         mEncPreset(encPreset),
+        mMinContentBoost(minContentBoost),
+        mMaxContentBoost(maxContentBoost),
         mMode(0){};
 
   UltraHdrAppInput(const char* gainmapMetadataCfgFile, const char* uhdrFile, const char* outputFile,
@@ -313,6 +317,8 @@ class UltraHdrAppInput {
         mGamma(1.0f),
         mEnableGLES(enableGLES),
         mEncPreset(UHDR_USAGE_REALTIME),
+        mMinContentBoost(FLT_MIN),
+        mMaxContentBoost(FLT_MAX),
         mMode(1){};
 
   ~UltraHdrAppInput() {
@@ -393,6 +399,8 @@ class UltraHdrAppInput {
   const float mGamma;
   const bool mEnableGLES;
   const uhdr_enc_preset_t mEncPreset;
+  const float mMinContentBoost;
+  const float mMaxContentBoost;
   const int mMode;
 
   uhdr_raw_image_t mRawP010Image{};
@@ -690,6 +698,9 @@ bool UltraHdrAppInput::encode() {
   RET_IF_ERR(uhdr_enc_set_gainmap_scale_factor(handle, mMapDimensionScaleFactor))
   RET_IF_ERR(uhdr_enc_set_gainmap_gamma(handle, mGamma))
   RET_IF_ERR(uhdr_enc_set_preset(handle, mEncPreset))
+  if (mMinContentBoost != FLT_MIN || mMaxContentBoost != FLT_MAX) {
+    RET_IF_ERR(uhdr_enc_set_min_max_content_boost(handle, mMinContentBoost, mMaxContentBoost))
+  }
   if (mEnableGLES) {
     RET_IF_ERR(uhdr_enable_gpu_acceleration(handle, mEnableGLES))
   }
@@ -1358,6 +1369,10 @@ static void usage(const char* name) {
   fprintf(
       stderr,
       "    -D    select encoding preset, optional. [0:real time (default), 1:best quality]. \n");
+  fprintf(stderr,
+          "    -k    min content boost recommendation, must be in linear scale, optional \n");
+  fprintf(stderr,
+          "    -k    max content boost recommendation, must be in linear scale, optional \n");
   fprintf(stderr, "    -x    binary input resource containing exif data to insert, optional. \n");
   fprintf(stderr, "\n## decoder options : \n");
   fprintf(stderr, "    -j    ultra hdr compressed input resource, required. \n");
@@ -1445,7 +1460,7 @@ static void usage(const char* name) {
 }
 
 int main(int argc, char* argv[]) {
-  char opt_string[] = "p:y:i:g:f:w:h:C:c:t:q:o:O:m:j:e:a:b:z:R:s:M:Q:G:x:u:D:";
+  char opt_string[] = "p:y:i:g:f:w:h:C:c:t:q:o:O:m:j:e:a:b:z:R:s:M:Q:G:x:u:D:k:K:";
   char *hdr_intent_raw_file = nullptr, *sdr_intent_raw_file = nullptr, *uhdr_file = nullptr,
        *sdr_intent_compressed_file = nullptr, *gainmap_compressed_file = nullptr,
        *gainmap_metadata_cfg_file = nullptr, *output_file = nullptr, *exif_file = nullptr;
@@ -1467,6 +1482,8 @@ int main(int argc, char* argv[]) {
   float gamma = 1.0f;
   bool enable_gles = false;
   uhdr_enc_preset_t enc_preset = UHDR_USAGE_REALTIME;
+  float min_content_boost = FLT_MIN;
+  float max_content_boost = FLT_MAX;
   int ch;
   while ((ch = getopt_s(argc, argv, opt_string)) != -1) {
     switch (ch) {
@@ -1555,6 +1572,12 @@ int main(int argc, char* argv[]) {
       case 'D':
         enc_preset = static_cast<uhdr_enc_preset_t>(atoi(optarg_s));
         break;
+      case 'k':
+        min_content_boost = atof(optarg_s);
+        break;
+      case 'K':
+        max_content_boost = atof(optarg_s);
+        break;
       default:
         usage(argv[0]);
         return -1;
@@ -1577,12 +1600,13 @@ int main(int argc, char* argv[]) {
       std::cerr << "did not receive raw resources for encoding." << std::endl;
       return -1;
     }
-    UltraHdrAppInput appInput(
-        hdr_intent_raw_file, sdr_intent_raw_file, sdr_intent_compressed_file,
-        gainmap_compressed_file, gainmap_metadata_cfg_file, exif_file,
-        output_file ? output_file : "out.jpeg", width, height, hdr_cf, sdr_cf, hdr_cg, sdr_cg,
-        hdr_tf, quality, out_tf, out_cf, use_full_range_color_hdr, gainmap_scale_factor,
-        gainmap_compression_quality, use_multi_channel_gainmap, gamma, enable_gles, enc_preset);
+    UltraHdrAppInput appInput(hdr_intent_raw_file, sdr_intent_raw_file, sdr_intent_compressed_file,
+                              gainmap_compressed_file, gainmap_metadata_cfg_file, exif_file,
+                              output_file ? output_file : "out.jpeg", width, height, hdr_cf, sdr_cf,
+                              hdr_cg, sdr_cg, hdr_tf, quality, out_tf, out_cf,
+                              use_full_range_color_hdr, gainmap_scale_factor,
+                              gainmap_compression_quality, use_multi_channel_gainmap, gamma,
+                              enable_gles, enc_preset, min_content_boost, max_content_boost);
     if (!appInput.encode()) return -1;
     if (compute_psnr == 1) {
       if (!appInput.decode()) return -1;

lib/include/ultrahdr/jpegr.h

@@ -77,7 +77,8 @@ class JpegR {
         size_t mapDimensionScaleFactor = kMapDimensionScaleFactorDefault,
         int mapCompressQuality = kMapCompressQualityDefault,
         bool useMultiChannelGainMap = kUseMultiChannelGainMapDefault,
-        float gamma = kGainMapGammaDefault, uhdr_enc_preset_t preset = UHDR_USAGE_REALTIME);
+        float gamma = kGainMapGammaDefault, uhdr_enc_preset_t preset = UHDR_USAGE_REALTIME,
+        float minContentBoost = FLT_MIN, float maxContentBoost = FLT_MAX);
 
   /*!\brief Encode API-0.
    *
@@ -572,6 +573,8 @@ class JpegR {
   bool mUseMultiChannelGainMap;     // enable multichannel gain map
   float mGamma;                     // gain map gamma parameter
   uhdr_enc_preset_t mEncPreset;     // encoding speed preset
+  float mMinContentBoost;           // min content boost recommendation
+  float mMaxContentBoost;           // max content boost recommendation
 };
 
 struct GlobalTonemapOutputs {

lib/include/ultrahdr/ultrahdrcommon.h

@@ -353,6 +353,8 @@ struct uhdr_encoder_private : uhdr_codec_private {
   bool m_use_multi_channel_gainmap;
   float m_gamma;
   uhdr_enc_preset_t m_enc_preset;
+  float m_min_content_boost;
+  float m_max_content_boost;
 
   // internal data
   std::unique_ptr<ultrahdr::uhdr_compressed_image_ext_t> m_compressed_output_buffer;

lib/src/jpegr.cpp

@@ -146,13 +146,16 @@ int GetCPUCoreCount() {
 }
 
 JpegR::JpegR(void* uhdrGLESCtxt, size_t mapDimensionScaleFactor, int mapCompressQuality,
-             bool useMultiChannelGainMap, float gamma, uhdr_enc_preset_t preset) {
+             bool useMultiChannelGainMap, float gamma, uhdr_enc_preset_t preset,
+             float minContentBoost, float maxContentBoost) {
   mUhdrGLESCtxt = uhdrGLESCtxt;
   mMapDimensionScaleFactor = mapDimensionScaleFactor;
   mMapCompressQuality = mapCompressQuality;
   mUseMultiChannelGainMap = useMultiChannelGainMap;
   mGamma = gamma;
   mEncPreset = preset;
+  mMinContentBoost = minContentBoost;
+  mMaxContentBoost = maxContentBoost;
 }
 
 /*
@@ -808,6 +811,14 @@ uhdr_error_info_t JpegR::generateGainMap(uhdr_raw_image_t* sdr_intent, uhdr_raw_
     // black from any sdr luminance. Allowing further excursion might not offer any benefit and on
     // the downside can cause bigger error during affine map and inverse map.
     min_content_boost_log2 = (std::max)(-13.0f, min_content_boost_log2);
+    if (this->mMaxContentBoost != FLT_MAX) {
+      float suggestion = log2(this->mMaxContentBoost);
+      max_content_boost_log2 = (std::min)(max_content_boost_log2, suggestion);
+    }
+    if (this->mMinContentBoost != FLT_MIN) {
+      float suggestion = log2(this->mMinContentBoost);
+      min_content_boost_log2 = (std::max)(min_content_boost_log2, suggestion);
+    }
     if (fabs(max_content_boost_log2 - min_content_boost_log2) < FLT_EPSILON) {
       max_content_boost_log2 += 0.1;  // to avoid div by zero during affine transform
     }

lib/src/ultrahdr_api.cpp

@@ -593,6 +593,52 @@ uhdr_error_info_t uhdr_enc_set_preset(uhdr_codec_private_t* enc, uhdr_enc_preset
   return status;
 }
 
+uhdr_error_info_t uhdr_enc_set_min_max_content_boost(uhdr_codec_private_t* enc, float min_boost,
+                                                     float max_boost) {
+  uhdr_error_info_t status = g_no_error;
+
+  if (dynamic_cast<uhdr_encoder_private*>(enc) == nullptr) {
+    status.error_code = UHDR_CODEC_INVALID_PARAM;
+    status.has_detail = 1;
+    snprintf(status.detail, sizeof status.detail, "received nullptr for uhdr codec instance");
+    return status;
+  }
+
+  if (max_boost < min_boost) {
+    status.error_code = UHDR_CODEC_INVALID_PARAM;
+    status.has_detail = 1;
+    snprintf(status.detail, sizeof status.detail,
+             "Invalid min boost / max boost configuration. configured max boost %f is less than "
+             "min boost %f",
+             max_boost, min_boost);
+    return status;
+  }
+
+  if (min_boost < 0) {
+    status.error_code = UHDR_CODEC_INVALID_PARAM;
+    status.has_detail = 1;
+    snprintf(status.detail, sizeof status.detail,
+             "Invalid min boost configuration. configured min boost %f is less than 0", min_boost);
+    return status;
+  }
+
+  uhdr_encoder_private* handle = dynamic_cast<uhdr_encoder_private*>(enc);
+
+  if (handle->m_sailed) {
+    status.error_code = UHDR_CODEC_INVALID_OPERATION;
+    status.has_detail = 1;
+    snprintf(status.detail, sizeof status.detail,
+             "An earlier call to uhdr_encode() has switched the context from configurable state to "
+             "end state. The context is no longer configurable. To reuse, call reset()");
+    return status;
+  }
+
+  handle->m_min_content_boost = min_boost;
+  handle->m_max_content_boost = max_boost;
+
+  return status;
+}
+
 uhdr_error_info_t uhdr_enc_set_raw_image(uhdr_codec_private_t* enc, uhdr_raw_image_t* img,
                                          uhdr_img_label_t intent) {
   uhdr_error_info_t status = g_no_error;
@@ -1050,7 +1096,8 @@ uhdr_error_info_t uhdr_encode(uhdr_codec_private_t* enc) {
 
     ultrahdr::JpegR jpegr(
         nullptr, handle->m_gainmap_scale_factor, handle->m_quality.find(UHDR_GAIN_MAP_IMG)->second,
-        handle->m_use_multi_channel_gainmap, handle->m_gamma, handle->m_enc_preset);
+        handle->m_use_multi_channel_gainmap, handle->m_gamma, handle->m_enc_preset,
+        handle->m_min_content_boost, handle->m_max_content_boost);
     if (handle->m_compressed_images.find(UHDR_BASE_IMG) != handle->m_compressed_images.end() &&
         handle->m_compressed_images.find(UHDR_GAIN_MAP_IMG) != handle->m_compressed_images.end()) {
       auto& base_entry = handle->m_compressed_images.find(UHDR_BASE_IMG)->second;
@@ -1151,6 +1198,8 @@ void uhdr_reset_encoder(uhdr_codec_private_t* enc) {
     handle->m_use_multi_channel_gainmap = ultrahdr::kUseMultiChannelGainMapDefault;
     handle->m_gamma = ultrahdr::kGainMapGammaDefault;
     handle->m_enc_preset = UHDR_USAGE_REALTIME;
+    handle->m_min_content_boost = FLT_MIN;
+    handle->m_max_content_boost = FLT_MAX;
 
     handle->m_compressed_output_buffer.reset();
     handle->m_encode_call_status = g_no_error;

ultrahdr_api.h

@@ -379,6 +379,20 @@ UHDR_EXTERN uhdr_error_info_t uhdr_enc_set_gainmap_scale_factor(uhdr_codec_priva
  */
 UHDR_EXTERN uhdr_error_info_t uhdr_enc_set_gainmap_gamma(uhdr_codec_private_t* enc, float gamma);
 
+/*!\brief Set min max content boost. This configuration is treated as a recommendation by the
+ * library. It is entirely possible for the library to use a different set of values. Value MUST be
+ * in linear scale.
+ *
+ * \param[in]  enc  encoder instance.
+ * \param[in]  min_boost min content boost
+ * \param[in]  max_boost max content boost
+ *
+ * \return uhdr_error_info_t #UHDR_CODEC_OK if operation succeeds,
+ *                           #UHDR_CODEC_INVALID_PARAM otherwise.
+ */
+UHDR_EXTERN uhdr_error_info_t uhdr_enc_set_min_max_content_boost(uhdr_codec_private_t* enc,
+                                                                 float min_boost, float max_boost);
+
 /*!\brief Set encoding preset. Tunes the encoder configurations for performance or quality. Default
  * configuration is #UHDR_USAGE_REALTIME.
  *