Allow for larger excursions of min, max content boost

Current implementation clips min/max content boost to a smaller range.
Allow for larger excursions for better hdr intent representation.

This is not enabled by default and is enabled in best quality encoding
preset.

Test: ./ultrahdr_app <options> -D 1
Test: ./ultrahdr_unit_test

Author: ram-mohan

examples/ultrahdr_app.cpp

@@ -244,17 +244,20 @@ static bool writeFile(const char* filename, uhdr_raw_image_t* img) {
 
 class UltraHdrAppInput {
  public:
-  UltraHdrAppInput(
-      const char* hdrIntentRawFile, const char* sdrIntentRawFile,
-      const char* sdrIntentCompressedFile, const char* gainmapCompressedFile,
-      const char* gainmapMetadataCfgFile, const char* exifFile, const char* outputFile,
-      size_t width, size_t height, uhdr_img_fmt_t hdrCf = UHDR_IMG_FMT_32bppRGBA1010102,
-      uhdr_img_fmt_t sdrCf = UHDR_IMG_FMT_32bppRGBA8888,
-      uhdr_color_gamut_t hdrCg = UHDR_CG_DISPLAY_P3, uhdr_color_gamut_t sdrCg = UHDR_CG_BT_709,
-      uhdr_color_transfer_t hdrTf = UHDR_CT_HLG, int quality = 95,
-      uhdr_color_transfer_t oTf = UHDR_CT_HLG, 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)
+  UltraHdrAppInput(const char* hdrIntentRawFile, const char* sdrIntentRawFile,
+                   const char* sdrIntentCompressedFile, const char* gainmapCompressedFile,
+                   const char* gainmapMetadataCfgFile, const char* exifFile, const char* outputFile,
+                   size_t width, size_t height,
+                   uhdr_img_fmt_t hdrCf = UHDR_IMG_FMT_32bppRGBA1010102,
+                   uhdr_img_fmt_t sdrCf = UHDR_IMG_FMT_32bppRGBA8888,
+                   uhdr_color_gamut_t hdrCg = UHDR_CG_DISPLAY_P3,
+                   uhdr_color_gamut_t sdrCg = UHDR_CG_BT_709,
+                   uhdr_color_transfer_t hdrTf = UHDR_CT_HLG, int quality = 95,
+                   uhdr_color_transfer_t oTf = UHDR_CT_HLG,
+                   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)
       : mHdrIntentRawFile(hdrIntentRawFile),
         mSdrIntentRawFile(sdrIntentRawFile),
         mSdrIntentCompressedFile(sdrIntentCompressedFile),
@@ -279,6 +282,7 @@ class UltraHdrAppInput {
         mUseMultiChannelGainMap(enableMultiChannelGainMap),
         mGamma(gamma),
         mEnableGLES(enableGLES),
+        mEncPreset(encPreset),
         mMode(0){};
 
   UltraHdrAppInput(const char* gainmapMetadataCfgFile, const char* uhdrFile, const char* outputFile,
@@ -308,6 +312,7 @@ class UltraHdrAppInput {
         mUseMultiChannelGainMap(false),
         mGamma(1.0f),
         mEnableGLES(enableGLES),
+        mEncPreset(UHDR_USAGE_REALTIME),
         mMode(1){};
 
   ~UltraHdrAppInput() {
@@ -387,6 +392,7 @@ class UltraHdrAppInput {
   const bool mUseMultiChannelGainMap;
   const float mGamma;
   const bool mEnableGLES;
+  const uhdr_enc_preset_t mEncPreset;
   const int mMode;
 
   uhdr_raw_image_t mRawP010Image{};
@@ -683,6 +689,7 @@ bool UltraHdrAppInput::encode() {
   RET_IF_ERR(uhdr_enc_set_using_multi_channel_gainmap(handle, mUseMultiChannelGainMap))
   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 (mEnableGLES) {
     RET_IF_ERR(uhdr_enable_gpu_acceleration(handle, mEnableGLES))
   }
@@ -1348,6 +1355,9 @@ static void usage(const char* name) {
           "real number (1.0 : default)].\n");
   fprintf(stderr,
           "    -M    select multi channel gain map, optional. [0:disable (default), 1:enable]. \n");
+  fprintf(
+      stderr,
+      "    -D    select encoding preset, optional. [0:real time (default), 1:best quality]. \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");
@@ -1425,7 +1435,7 @@ static void usage(const char* name) {
   fprintf(stderr, "\n## encode at high quality :\n");
   fprintf(stderr,
           "    ultrahdr_app -m 0 -p hdr_intent.raw -y sdr_intent.raw -w 640 -h 480 -c <select> -C "
-          "<select> -t <select> -s 1 -M 1 -Q 98 -q 98\n");
+          "<select> -t <select> -s 1 -M 1 -Q 98 -q 98 -D 1\n");
 
   fprintf(stderr, "\n## decode api :\n");
   fprintf(stderr, "    ultrahdr_app -m 1 -j cosmat_1920x1080_hdr.jpg \n");
@@ -1435,7 +1445,7 @@ 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:";
+  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 *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;
@@ -1456,6 +1466,7 @@ int main(int argc, char* argv[]) {
   int compute_psnr = 0;
   float gamma = 1.0f;
   bool enable_gles = false;
+  uhdr_enc_preset_t enc_preset = UHDR_USAGE_REALTIME;
   int ch;
   while ((ch = getopt_s(argc, argv, opt_string)) != -1) {
     switch (ch) {
@@ -1541,6 +1552,9 @@ int main(int argc, char* argv[]) {
       case 'u':
         enable_gles = atoi(optarg_s) == 1 ? true : false;
         break;
+      case 'D':
+        enc_preset = static_cast<uhdr_enc_preset_t>(atoi(optarg_s));
+        break;
       default:
         usage(argv[0]);
         return -1;
@@ -1568,7 +1582,7 @@ int main(int argc, char* argv[]) {
         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);
+        gainmap_compression_quality, use_multi_channel_gainmap, gamma, enable_gles, enc_preset);
     if (!appInput.encode()) return -1;
     if (compute_psnr == 1) {
       if (!appInput.decode()) return -1;

fuzzer/ultrahdr_enc_fuzzer.cpp

@@ -113,6 +113,9 @@ void UltraHdrEncFuzzer::process() {
     // gainmap scale factor
     auto gm_scale_factor = mFdp.ConsumeIntegralInRange<int>(1, 128);
 
+    // encoding speed preset
+    auto enc_preset = static_cast<uhdr_enc_preset_t>(mFdp.ConsumeIntegralInRange<int>(0, 1));
+
     std::unique_ptr<uint32_t[]> bufferHdr = nullptr;
     std::unique_ptr<uint16_t[]> bufferYHdr = nullptr;
     std::unique_ptr<uint16_t[]> bufferUVHdr = nullptr;
@@ -265,6 +268,7 @@ void UltraHdrEncFuzzer::process() {
     ON_ERR(uhdr_enc_set_quality(enc_handle, gainmap_quality, UHDR_GAIN_MAP_IMG))
     ON_ERR(uhdr_enc_set_gainmap_scale_factor(enc_handle, gm_scale_factor))
     ON_ERR(uhdr_enc_set_using_multi_channel_gainmap(enc_handle, multi_channel_gainmap))
+    ON_ERR(uhdr_enc_set_preset(enc_handle, enc_preset))
 
     uhdr_error_info_t status = {UHDR_CODEC_OK, 0, ""};
     if (muxSwitch == 0 || muxSwitch == 1) {  // api 0 or api 1

lib/include/ultrahdr/gainmapmath.h

@@ -194,7 +194,7 @@ struct GainLUT {
 
   GainLUT(uhdr_gainmap_metadata_ext_t* metadata, float displayBoost) {
     this->mGammaInv = 1.0f / metadata->gamma;
-    float boostFactor = displayBoost > 0 ? displayBoost / metadata->max_content_boost : 1.0f;
+    float boostFactor = displayBoost > 0 ? displayBoost / metadata->hdr_capacity_max : 1.0f;
     for (int32_t idx = 0; idx < kGainFactorNumEntries; idx++) {
       float value = static_cast<float>(idx) / static_cast<float>(kGainFactorNumEntries - 1);
       float logBoost = log2(metadata->min_content_boost) * (1.0f - value) +
@@ -540,23 +540,17 @@ void transformYuv444(uhdr_raw_image_t* image, const std::array<float, 9>& coeffs
 
 /*
  * Calculate the 8-bit unsigned integer gain value for the given SDR and HDR
- * luminances in linear space, and the hdr ratio to encode against.
- *
- * Note: since this library always uses gamma of 1.0, offsetSdr of 0.0, and
- * offsetHdr of 0.0, this function doesn't handle different metadata values for
- * these fields.
+ * luminances in linear space and gainmap metadata fields.
  */
 uint8_t encodeGain(float y_sdr, float y_hdr, uhdr_gainmap_metadata_ext_t* metadata);
 uint8_t encodeGain(float y_sdr, float y_hdr, uhdr_gainmap_metadata_ext_t* metadata,
                    float log2MinContentBoost, float log2MaxContentBoost);
+float computeGain(float sdr, float hdr);
+uint8_t affineMapGain(float gainlog2, float mingainlog2, float maxgainlog2, float gamma);
 
 /*
  * Calculates the linear luminance in nits after applying the given gain
  * value, with the given hdr ratio, to the given sdr input in the range [0, 1].
- *
- * Note: similar to encodeGain(), this function only supports gamma 1.0,
- * offsetSdr 0.0, offsetHdr 0.0, hdrCapacityMin 1.0, and hdrCapacityMax equal to
- * gainMapMax, as this library encodes.
  */
 Color applyGain(Color e, float gain, uhdr_gainmap_metadata_ext_t* metadata);
 Color applyGain(Color e, float gain, uhdr_gainmap_metadata_ext_t* metadata, float displayBoost);
@@ -565,10 +559,6 @@ Color applyGainLUT(Color e, float gain, GainLUT& gainLUT);
 /*
  * Apply gain in R, G and B channels, with the given hdr ratio, to the given sdr input
  * in the range [0, 1].
- *
- * Note: similar to encodeGain(), this function only supports gamma 1.0,
- * offsetSdr 0.0, offsetHdr 0.0, hdrCapacityMin 1.0, and hdrCapacityMax equal to
- * gainMapMax, as this library encodes.
  */
 Color applyGain(Color e, Color gain, uhdr_gainmap_metadata_ext_t* metadata);
 Color applyGain(Color e, Color gain, uhdr_gainmap_metadata_ext_t* metadata, float displayBoost);

lib/include/ultrahdr/jpegr.h

@@ -77,7 +77,7 @@ class JpegR {
         size_t mapDimensionScaleFactor = kMapDimensionScaleFactorDefault,
         int mapCompressQuality = kMapCompressQualityDefault,
         bool useMultiChannelGainMap = kUseMultiChannelGainMapDefault,
-        float gamma = kGainMapGammaDefault);
+        float gamma = kGainMapGammaDefault, uhdr_enc_preset_t preset = UHDR_USAGE_REALTIME);
 
   /*!\brief Encode API-0.
    *
@@ -571,6 +571,7 @@ class JpegR {
   int mMapCompressQuality;          // gain map quality factor
   bool mUseMultiChannelGainMap;     // enable multichannel gain map
   float mGamma;                     // gain map gamma parameter
+  uhdr_enc_preset_t mEncPreset;     // encoding speed preset
 };
 
 struct GlobalTonemapOutputs {

lib/include/ultrahdr/ultrahdrcommon.h

@@ -327,6 +327,7 @@ struct uhdr_encoder_private : uhdr_codec_private {
   int m_gainmap_scale_factor;
   bool m_use_multi_channel_gainmap;
   float m_gamma;
+  uhdr_enc_preset_t m_enc_preset;
 
   // internal data
   std::unique_ptr<ultrahdr::uhdr_compressed_image_ext_t> m_compressed_output_buffer;

lib/src/gainmapmath.cpp

@@ -490,7 +490,7 @@ SamplePixelFn getSamplePixelFn(uhdr_img_fmt_t format) {
 float getMaxDisplayMasteringLuminance(uhdr_color_transfer_t transfer) {
   switch (transfer) {
     case UHDR_CT_LINEAR:
-      // TODO: configure maxCLL correctly for linear tf
+      // TODO: configure MDML correctly for linear tf
       return kHlgMaxNits;
     case UHDR_CT_HLG:
       return kHlgMaxNits;
@@ -647,6 +647,22 @@ uint8_t encodeGain(float y_sdr, float y_hdr, uhdr_gainmap_metadata_ext_t* metada
   return static_cast<uint8_t>(gain_normalized_gamma * 255.0f);
 }
 
+float computeGain(float sdr, float hdr) {
+  if (sdr == 0.0f) return 0.0f;  // for sdr black return no gain
+  if (hdr == 0.0f) {  // for hdr black, return a gain large enough to attenuate the sdr pel
+    float offset = (1.0f / 64);
+    return log2(offset / (offset + sdr));
+  }
+  return log2(hdr / sdr);
+}
+
+uint8_t affineMapGain(float gainlog2, float mingainlog2, float maxgainlog2, float gamma) {
+  float mappedVal = (gainlog2 - mingainlog2) / (maxgainlog2 - mingainlog2);
+  if (gamma != 1.0f) mappedVal = pow(mappedVal, gamma);
+  mappedVal *= 255;
+  return CLIP3(mappedVal + 0.5f, 0, 255);
+}
+
 Color applyGain(Color e, float gain, uhdr_gainmap_metadata_ext_t* metadata) {
   gain = pow(gain, 1.0f / metadata->gamma);
   float logBoost =
@@ -659,7 +675,7 @@ Color applyGain(Color e, float gain, uhdr_gainmap_metadata_ext_t* metadata, floa
   gain = pow(gain, 1.0f / metadata->gamma);
   float logBoost =
       log2(metadata->min_content_boost) * (1.0f - gain) + log2(metadata->max_content_boost) * gain;
-  float gainFactor = exp2(logBoost * displayBoost / metadata->max_content_boost);
+  float gainFactor = exp2(logBoost * displayBoost / metadata->hdr_capacity_max);
   return e * gainFactor;
 }
 
@@ -694,9 +710,9 @@ Color applyGain(Color e, Color gain, uhdr_gainmap_metadata_ext_t* metadata, floa
                     log2(metadata->max_content_boost) * gain.g;
   float logBoostB = log2(metadata->min_content_boost) * (1.0f - gain.b) +
                     log2(metadata->max_content_boost) * gain.b;
-  float gainFactorR = exp2(logBoostR * displayBoost / metadata->max_content_boost);
-  float gainFactorG = exp2(logBoostG * displayBoost / metadata->max_content_boost);
-  float gainFactorB = exp2(logBoostB * displayBoost / metadata->max_content_boost);
+  float gainFactorR = exp2(logBoostR * displayBoost / metadata->hdr_capacity_max);
+  float gainFactorG = exp2(logBoostG * displayBoost / metadata->hdr_capacity_max);
+  float gainFactorB = exp2(logBoostB * displayBoost / metadata->hdr_capacity_max);
   return {{{e.r * gainFactorR, e.g * gainFactorG, e.b * gainFactorB}}};
 }