diff --git a/libs/ultrahdr/fuzzer/ultrahdr_enc_fuzzer.cpp b/libs/ultrahdr/fuzzer/ultrahdr_enc_fuzzer.cpp
index acb9b79..bbe58e0 100644
--- a/libs/ultrahdr/fuzzer/ultrahdr_enc_fuzzer.cpp
+++ b/libs/ultrahdr/fuzzer/ultrahdr_enc_fuzzer.cpp
@@ -249,7 +249,7 @@
                         jpegGainMap.data = gainMapEncoder.getCompressedImagePtr();
                         jpegGainMap.colorGamut = ULTRAHDR_COLORGAMUT_UNSPECIFIED;
                         ultrahdr_metadata_struct metadata;
-                        metadata.version = "1.3.1";
+                        metadata.version = "1.0";
                         if (tf == ULTRAHDR_TF_HLG) {
                             metadata.maxContentBoost = kHlgMaxNits / kSdrWhiteNits;
                         } else if (tf == ULTRAHDR_TF_PQ) {
@@ -258,6 +258,11 @@
                             metadata.maxContentBoost = 1.0f;
                         }
                         metadata.minContentBoost = 1.0f;
+                        metadata.gamma = 1.0f;
+                        metadata.offsetSdr = 0.0f;
+                        metadata.offsetHdr = 0.0f;
+                        metadata.hdrCapacityMin = 1.0f;
+                        metadata.hdrCapacityMax = metadata.maxContentBoost;
                         status = jpegHdr.encodeJPEGR(&jpegImg, &jpegGainMap, &metadata, &jpegImgR);
                     }
                 }
diff --git a/libs/ultrahdr/include/ultrahdr/gainmapmath.h b/libs/ultrahdr/include/ultrahdr/gainmapmath.h
index 13832db..edf152d 100644
--- a/libs/ultrahdr/include/ultrahdr/gainmapmath.h
+++ b/libs/ultrahdr/include/ultrahdr/gainmapmath.h
@@ -414,6 +414,10 @@
 /*
  * 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.
  */
 uint8_t encodeGain(float y_sdr, float y_hdr, ultrahdr_metadata_ptr metadata);
 uint8_t encodeGain(float y_sdr, float y_hdr, ultrahdr_metadata_ptr metadata,
@@ -422,6 +426,10 @@
 /*
  * 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, ultrahdr_metadata_ptr metadata);
 Color applyGain(Color e, float gain, ultrahdr_metadata_ptr metadata, float displayBoost);
diff --git a/libs/ultrahdr/include/ultrahdr/jpegr.h b/libs/ultrahdr/include/ultrahdr/jpegr.h
index 9546ca4..a35fd30 100644
--- a/libs/ultrahdr/include/ultrahdr/jpegr.h
+++ b/libs/ultrahdr/include/ultrahdr/jpegr.h
@@ -222,7 +222,11 @@
      * Decompress JPEGR image.
      *
      * This method assumes that the JPEGR image contains an ICC profile with primaries that match
-     * those of a color gamut that this library is aware of; Bt.709, Display-P3, or Bt.2100.
+     * those of a color gamut that this library is aware of; Bt.709, Display-P3, or Bt.2100. It also
+     * assumes the base image uses the sRGB transfer function.
+     *
+     * This method only supports single gain map metadata values for fields that allow multi-channel
+     * metadata values.
      *
      * @param compressed_jpegr_image compressed JPEGR image.
      * @param dest destination of the uncompressed JPEGR image.
@@ -265,6 +269,9 @@
     /*
     * Gets Info from JPEGR file without decoding it.
     *
+    * This method only supports single gain map metadata values for fields that allow multi-channel
+    * metadata values.
+    *
     * The output is filled jpegr_info structure
     * @param compressed_jpegr_image compressed JPEGR image
     * @param jpegr_info pointer to output JPEGR info. Members of jpegr_info
diff --git a/libs/ultrahdr/include/ultrahdr/jpegrerrorcode.h b/libs/ultrahdr/include/ultrahdr/jpegrerrorcode.h
index 9f59c3e..0641232 100644
--- a/libs/ultrahdr/include/ultrahdr/jpegrerrorcode.h
+++ b/libs/ultrahdr/include/ultrahdr/jpegrerrorcode.h
@@ -42,6 +42,8 @@
     ERROR_JPEGR_BUFFER_TOO_SMALL        = JPEGR_IO_ERROR_BASE - 4,
     ERROR_JPEGR_INVALID_COLORGAMUT      = JPEGR_IO_ERROR_BASE - 5,
     ERROR_JPEGR_INVALID_TRANS_FUNC      = JPEGR_IO_ERROR_BASE - 6,
+    ERROR_JPEGR_INVALID_METADATA        = JPEGR_IO_ERROR_BASE - 7,
+    ERROR_JPEGR_UNSUPPORTED_METADATA    = JPEGR_IO_ERROR_BASE - 8,
 
     JPEGR_RUNTIME_ERROR_BASE            = -20000,
     ERROR_JPEGR_ENCODE_ERROR            = JPEGR_RUNTIME_ERROR_BASE - 1,
diff --git a/libs/ultrahdr/include/ultrahdr/ultrahdr.h b/libs/ultrahdr/include/ultrahdr/ultrahdr.h
index 21751b4..17cc971 100644
--- a/libs/ultrahdr/include/ultrahdr/ultrahdr.h
+++ b/libs/ultrahdr/include/ultrahdr/ultrahdr.h
@@ -49,14 +49,28 @@
 
 /*
  * Holds information for gain map related metadata.
+ *
+ * Not: all values stored in linear. This differs from the metadata encoding in XMP, where
+ * maxContentBoost (aka gainMapMax), minContentBoost (aka gainMapMin), hdrCapacityMin, and
+ * hdrCapacityMax are stored in log2 space.
  */
 struct ultrahdr_metadata_struct {
-  // Ultra HDR library version
+  // Ultra HDR format version
   std::string version;
   // Max Content Boost for the map
   float maxContentBoost;
   // Min Content Boost for the map
   float minContentBoost;
+  // Gamma of the map data
+  float gamma;
+  // Offset for SDR data in map calculations
+  float offsetSdr;
+  // Offset for HDR data in map calculations
+  float offsetHdr;
+  // HDR capacity to apply the map at all
+  float hdrCapacityMin;
+  // HDR capacity to apply the map completely
+  float hdrCapacityMax;
 };
 typedef struct ultrahdr_metadata_struct* ultrahdr_metadata_ptr;
 
diff --git a/libs/ultrahdr/jpegr.cpp b/libs/ultrahdr/jpegr.cpp
index 9af5af7..9c57f34 100644
--- a/libs/ultrahdr/jpegr.cpp
+++ b/libs/ultrahdr/jpegr.cpp
@@ -644,13 +644,18 @@
   ultrahdr_metadata_struct uhdr_metadata;
   if (!getMetadataFromXMP(static_cast<uint8_t*>(gain_map_decoder.getXMPPtr()),
                           gain_map_decoder.getXMPSize(), &uhdr_metadata)) {
-    return ERROR_JPEGR_DECODE_ERROR;
+    return ERROR_JPEGR_INVALID_METADATA;
   }
 
   if (metadata != nullptr) {
       metadata->version = uhdr_metadata.version;
       metadata->minContentBoost = uhdr_metadata.minContentBoost;
       metadata->maxContentBoost = uhdr_metadata.maxContentBoost;
+      metadata->gamma = uhdr_metadata.gamma;
+      metadata->offsetSdr = uhdr_metadata.offsetSdr;
+      metadata->offsetHdr = uhdr_metadata.offsetHdr;
+      metadata->hdrCapacityMin = uhdr_metadata.hdrCapacityMin;
+      metadata->hdrCapacityMax = uhdr_metadata.hdrCapacityMax;
   }
 
   if (output_format == ULTRAHDR_OUTPUT_SDR) {
@@ -840,6 +845,12 @@
 
   metadata->maxContentBoost = hdr_white_nits / kSdrWhiteNits;
   metadata->minContentBoost = 1.0f;
+  metadata->gamma = 1.0f;
+  metadata->offsetSdr = 0.0f;
+  metadata->offsetHdr = 0.0f;
+  metadata->hdrCapacityMin = 1.0f;
+  metadata->hdrCapacityMax = metadata->maxContentBoost;
+
   float log2MinBoost = log2(metadata->minContentBoost);
   float log2MaxBoost = log2(metadata->maxContentBoost);
 
@@ -958,6 +969,26 @@
     return ERROR_JPEGR_INVALID_NULL_PTR;
   }
 
+  if (metadata->version.compare("1.0")) {
+      ALOGE("Unsupported metadata version: %s", metadata->version.c_str());
+      return ERROR_JPEGR_UNSUPPORTED_METADATA;
+  }
+  if (metadata->gamma != 1.0f) {
+      ALOGE("Unsupported metadata gamma: %f", metadata->gamma);
+      return ERROR_JPEGR_UNSUPPORTED_METADATA;
+  }
+  if (metadata->offsetSdr != 0.0f || metadata->offsetHdr != 0.0f) {
+      ALOGE("Unsupported metadata offset sdr, hdr: %f, %f", metadata->offsetSdr,
+            metadata->offsetHdr);
+      return ERROR_JPEGR_UNSUPPORTED_METADATA;
+  }
+  if (metadata->hdrCapacityMin != metadata->minContentBoost
+   || metadata->hdrCapacityMax != metadata->maxContentBoost) {
+      ALOGE("Unsupported metadata hdr capacity min, max: %f, %f", metadata->hdrCapacityMin,
+            metadata->hdrCapacityMax);
+      return ERROR_JPEGR_UNSUPPORTED_METADATA;
+  }
+
   // TODO: remove once map scaling factor is computed based on actual map dims
   size_t image_width = uncompressed_yuv_420_image->width;
   size_t image_height = uncompressed_yuv_420_image->height;
@@ -1180,12 +1211,33 @@
     return ERROR_JPEGR_INVALID_NULL_PTR;
   }
 
-  if (metadata->minContentBoost < 1.0f || metadata->maxContentBoost < metadata->minContentBoost) {
+  if (metadata->version.compare("1.0")) {
+    ALOGE("received bad value for version: %s", metadata->version.c_str());
+    return ERROR_JPEGR_INVALID_INPUT_TYPE;
+  }
+  if (metadata->maxContentBoost < metadata->minContentBoost) {
     ALOGE("received bad value for content boost min %f, max %f", metadata->minContentBoost,
            metadata->maxContentBoost);
     return ERROR_JPEGR_INVALID_INPUT_TYPE;
   }
 
+  if (metadata->hdrCapacityMax < metadata->hdrCapacityMin || metadata->hdrCapacityMin < 1.0f) {
+    ALOGE("received bad value for hdr capacity min %f, max %f", metadata->hdrCapacityMin,
+           metadata->hdrCapacityMax);
+    return ERROR_JPEGR_INVALID_INPUT_TYPE;
+  }
+
+  if (metadata->offsetSdr < 0.0f || metadata->offsetHdr < 0.0f) {
+    ALOGE("received bad value for offset sdr %f, hdr %f", metadata->offsetSdr,
+           metadata->offsetHdr);
+    return ERROR_JPEGR_INVALID_INPUT_TYPE;
+  }
+
+  if (metadata->gamma <= 0.0f) {
+    ALOGE("received bad value for gamma %f", metadata->gamma);
+    return ERROR_JPEGR_INVALID_INPUT_TYPE;
+  }
+
   const string nameSpace = "http://ns.adobe.com/xap/1.0/";
   const int nameSpaceLength = nameSpace.size() + 1;  // need to count the null terminator
 
diff --git a/libs/ultrahdr/jpegrutils.cpp b/libs/ultrahdr/jpegrutils.cpp
index 6430af1..c434eb6 100644
--- a/libs/ultrahdr/jpegrutils.cpp
+++ b/libs/ultrahdr/jpegrutils.cpp
@@ -113,6 +113,15 @@
 
     XMPXmlHandler() : XmlHandler() {
         state = NotStrarted;
+        versionFound = false;
+        minContentBoostFound = false;
+        maxContentBoostFound = false;
+        gammaFound = false;
+        offsetSdrFound = false;
+        offsetHdrFound = false;
+        hdrCapacityMinFound = false;
+        hdrCapacityMaxFound = false;
+        baseRenditionIsHdrFound = false;
     }
 
     enum ParseState {
@@ -147,10 +156,24 @@
         string val;
         if (state == Started) {
             if (context.BuildTokenValue(&val)) {
-                if (!val.compare(maxContentBoostAttrName)) {
+                if (!val.compare(versionAttrName)) {
+                    lastAttributeName = versionAttrName;
+                } else if (!val.compare(maxContentBoostAttrName)) {
                     lastAttributeName = maxContentBoostAttrName;
                 } else if (!val.compare(minContentBoostAttrName)) {
                     lastAttributeName = minContentBoostAttrName;
+                } else if (!val.compare(gammaAttrName)) {
+                    lastAttributeName = gammaAttrName;
+                } else if (!val.compare(offsetSdrAttrName)) {
+                    lastAttributeName = offsetSdrAttrName;
+                } else if (!val.compare(offsetHdrAttrName)) {
+                    lastAttributeName = offsetHdrAttrName;
+                } else if (!val.compare(hdrCapacityMinAttrName)) {
+                    lastAttributeName = hdrCapacityMinAttrName;
+                } else if (!val.compare(hdrCapacityMaxAttrName)) {
+                    lastAttributeName = hdrCapacityMaxAttrName;
+                } else if (!val.compare(baseRenditionIsHdrAttrName)) {
+                    lastAttributeName = baseRenditionIsHdrAttrName;
                 } else {
                     lastAttributeName = "";
                 }
@@ -163,18 +186,52 @@
         string val;
         if (state == Started) {
             if (context.BuildTokenValue(&val, true)) {
-                if (!lastAttributeName.compare(maxContentBoostAttrName)) {
+                if (!lastAttributeName.compare(versionAttrName)) {
+                    versionStr = val;
+                    versionFound = true;
+                } else if (!lastAttributeName.compare(maxContentBoostAttrName)) {
                     maxContentBoostStr = val;
+                    maxContentBoostFound = true;
                 } else if (!lastAttributeName.compare(minContentBoostAttrName)) {
                     minContentBoostStr = val;
+                    minContentBoostFound = true;
+                } else if (!lastAttributeName.compare(gammaAttrName)) {
+                    gammaStr = val;
+                    gammaFound = true;
+                } else if (!lastAttributeName.compare(offsetSdrAttrName)) {
+                    offsetSdrStr = val;
+                    offsetSdrFound = true;
+                } else if (!lastAttributeName.compare(offsetHdrAttrName)) {
+                    offsetHdrStr = val;
+                    offsetHdrFound = true;
+                } else if (!lastAttributeName.compare(hdrCapacityMinAttrName)) {
+                    hdrCapacityMinStr = val;
+                    hdrCapacityMinFound = true;
+                } else if (!lastAttributeName.compare(hdrCapacityMaxAttrName)) {
+                    hdrCapacityMaxStr = val;
+                    hdrCapacityMaxFound = true;
+                } else if (!lastAttributeName.compare(baseRenditionIsHdrAttrName)) {
+                    baseRenditionIsHdrStr = val;
+                    baseRenditionIsHdrFound = true;
                 }
             }
         }
         return context.GetResult();
     }
 
-    bool getMaxContentBoost(float* max_content_boost) {
+    bool getVersion(string* version, bool* present) {
         if (state == Done) {
+            *version = versionStr;
+            *present = versionFound;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    bool getMaxContentBoost(float* max_content_boost, bool* present) {
+        if (state == Done) {
+            *present = maxContentBoostFound;
             stringstream ss(maxContentBoostStr);
             float val;
             if (ss >> val) {
@@ -188,8 +245,9 @@
         }
     }
 
-    bool getMinContentBoost(float* min_content_boost) {
+    bool getMinContentBoost(float* min_content_boost, bool* present) {
         if (state == Done) {
+            *present = minContentBoostFound;
             stringstream ss(minContentBoostStr);
             float val;
             if (ss >> val) {
@@ -203,12 +261,141 @@
         }
     }
 
+    bool getGamma(float* gamma, bool* present) {
+        if (state == Done) {
+            *present = gammaFound;
+            stringstream ss(gammaStr);
+            float val;
+            if (ss >> val) {
+                *gamma = val;
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
+    bool getOffsetSdr(float* offset_sdr, bool* present) {
+        if (state == Done) {
+            *present = offsetSdrFound;
+            stringstream ss(offsetSdrStr);
+            float val;
+            if (ss >> val) {
+                *offset_sdr = val;
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
+    bool getOffsetHdr(float* offset_hdr, bool* present) {
+        if (state == Done) {
+            *present = offsetHdrFound;
+            stringstream ss(offsetHdrStr);
+            float val;
+            if (ss >> val) {
+                *offset_hdr = val;
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
+    bool getHdrCapacityMin(float* hdr_capacity_min, bool* present) {
+        if (state == Done) {
+            *present = hdrCapacityMinFound;
+            stringstream ss(hdrCapacityMinStr);
+            float val;
+            if (ss >> val) {
+                *hdr_capacity_min = exp2(val);
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
+    bool getHdrCapacityMax(float* hdr_capacity_max, bool* present) {
+        if (state == Done) {
+            *present = hdrCapacityMaxFound;
+            stringstream ss(hdrCapacityMaxStr);
+            float val;
+            if (ss >> val) {
+                *hdr_capacity_max = exp2(val);
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
+    bool getBaseRenditionIsHdr(bool* base_rendition_is_hdr, bool* present) {
+        if (state == Done) {
+            *present = baseRenditionIsHdrFound;
+            if (!baseRenditionIsHdrStr.compare("False")) {
+                *base_rendition_is_hdr = false;
+                return true;
+            } else if (!baseRenditionIsHdrStr.compare("True")) {
+                *base_rendition_is_hdr = true;
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+
+
 private:
     static const string containerName;
+
+    static const string versionAttrName;
+    string              versionStr;
+    bool                versionFound;
     static const string maxContentBoostAttrName;
     string              maxContentBoostStr;
+    bool                maxContentBoostFound;
     static const string minContentBoostAttrName;
     string              minContentBoostStr;
+    bool                minContentBoostFound;
+    static const string gammaAttrName;
+    string              gammaStr;
+    bool                gammaFound;
+    static const string offsetSdrAttrName;
+    string              offsetSdrStr;
+    bool                offsetSdrFound;
+    static const string offsetHdrAttrName;
+    string              offsetHdrStr;
+    bool                offsetHdrFound;
+    static const string hdrCapacityMinAttrName;
+    string              hdrCapacityMinStr;
+    bool                hdrCapacityMinFound;
+    static const string hdrCapacityMaxAttrName;
+    string              hdrCapacityMaxStr;
+    bool                hdrCapacityMaxFound;
+    static const string baseRenditionIsHdrAttrName;
+    string              baseRenditionIsHdrStr;
+    bool                baseRenditionIsHdrFound;
+
     string              lastAttributeName;
     ParseState          state;
 };
@@ -253,8 +440,15 @@
 const string kMapBaseRenditionIsHDR = Name(kGainMapPrefix, "BaseRenditionIsHDR");
 
 // GainMap XMP constants - names for XMP handlers
+const string XMPXmlHandler::versionAttrName = kMapVersion;
 const string XMPXmlHandler::minContentBoostAttrName = kMapGainMapMin;
 const string XMPXmlHandler::maxContentBoostAttrName = kMapGainMapMax;
+const string XMPXmlHandler::gammaAttrName = kMapGamma;
+const string XMPXmlHandler::offsetSdrAttrName = kMapOffsetSdr;
+const string XMPXmlHandler::offsetHdrAttrName = kMapOffsetHdr;
+const string XMPXmlHandler::hdrCapacityMinAttrName = kMapHDRCapacityMin;
+const string XMPXmlHandler::hdrCapacityMaxAttrName = kMapHDRCapacityMax;
+const string XMPXmlHandler::baseRenditionIsHdrAttrName = kMapBaseRenditionIsHDR;
 
 bool getMetadataFromXMP(uint8_t* xmp_data, size_t xmp_size, ultrahdr_metadata_struct* metadata) {
     string nameSpace = "http://ns.adobe.com/xap/1.0/\0";
@@ -291,11 +485,48 @@
         return false;
     }
 
-    if (!handler.getMaxContentBoost(&metadata->maxContentBoost)) {
+    // Apply default values to any not-present fields, except for Version,
+    // maxContentBoost, and hdrCapacityMax, which are required. Return false if
+    // we encounter a present field that couldn't be parsed, since this
+    // indicates it is invalid (eg. string where there should be a float).
+    bool present = false;
+    if (!handler.getVersion(&metadata->version, &present) || !present) {
         return false;
     }
+    if (!handler.getMaxContentBoost(&metadata->maxContentBoost, &present) || !present) {
+        return false;
+    }
+    if (!handler.getHdrCapacityMax(&metadata->hdrCapacityMax, &present) || !present) {
+        return false;
+    }
+    if (!handler.getMinContentBoost(&metadata->minContentBoost, &present)) {
+        if (present) return false;
+        metadata->minContentBoost = 1.0f;
+    }
+    if (!handler.getGamma(&metadata->gamma, &present)) {
+        if (present) return false;
+        metadata->gamma = 1.0f;
+    }
+    if (!handler.getOffsetSdr(&metadata->offsetSdr, &present)) {
+        if (present) return false;
+        metadata->offsetSdr = 1.0f / 64.0f;
+    }
+    if (!handler.getOffsetHdr(&metadata->offsetHdr, &present)) {
+        if (present) return false;
+        metadata->offsetHdr = 1.0f / 64.0f;
+    }
+    if (!handler.getHdrCapacityMin(&metadata->hdrCapacityMin, &present)) {
+        if (present) return false;
+        metadata->hdrCapacityMin = 1.0f;
+    }
 
-    if (!handler.getMinContentBoost(&metadata->minContentBoost)) {
+    bool base_rendition_is_hdr;
+    if (!handler.getBaseRenditionIsHdr(&base_rendition_is_hdr, &present)) {
+        if (present) return false;
+        base_rendition_is_hdr = false;
+    }
+    if (base_rendition_is_hdr) {
+        ALOGE("Base rendition of HDR is not supported!");
         return false;
     }
 
@@ -355,12 +586,11 @@
   writer.WriteAttributeNameAndValue(kMapVersion, metadata.version);
   writer.WriteAttributeNameAndValue(kMapGainMapMin, log2(metadata.minContentBoost));
   writer.WriteAttributeNameAndValue(kMapGainMapMax, log2(metadata.maxContentBoost));
-  writer.WriteAttributeNameAndValue(kMapGamma, "1");
-  writer.WriteAttributeNameAndValue(kMapOffsetSdr, "0");
-  writer.WriteAttributeNameAndValue(kMapOffsetHdr, "0");
-  writer.WriteAttributeNameAndValue(
-      kMapHDRCapacityMin, std::max(log2(metadata.minContentBoost), 0.0f));
-  writer.WriteAttributeNameAndValue(kMapHDRCapacityMax, log2(metadata.maxContentBoost));
+  writer.WriteAttributeNameAndValue(kMapGamma, metadata.gamma);
+  writer.WriteAttributeNameAndValue(kMapOffsetSdr, metadata.offsetSdr);
+  writer.WriteAttributeNameAndValue(kMapOffsetHdr, metadata.offsetHdr);
+  writer.WriteAttributeNameAndValue(kMapHDRCapacityMin, log2(metadata.hdrCapacityMin));
+  writer.WriteAttributeNameAndValue(kMapHDRCapacityMax, log2(metadata.hdrCapacityMax));
   writer.WriteAttributeNameAndValue(kMapBaseRenditionIsHDR, "False");
   writer.FinishWriting();
 
diff --git a/libs/ultrahdr/tests/data/minnie-320x240-yuv-icc.jpg b/libs/ultrahdr/tests/data/minnie-320x240-yuv-icc.jpg
index f61e0e8..c7f4538 100644
--- a/libs/ultrahdr/tests/data/minnie-320x240-yuv-icc.jpg
+++ b/libs/ultrahdr/tests/data/minnie-320x240-yuv-icc.jpg
Binary files differ
diff --git a/libs/ultrahdr/tests/jpegr_test.cpp b/libs/ultrahdr/tests/jpegr_test.cpp
index d482ea1..41d55ec 100644
--- a/libs/ultrahdr/tests/jpegr_test.cpp
+++ b/libs/ultrahdr/tests/jpegr_test.cpp
@@ -819,6 +819,52 @@
   EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
       &jpegR, nullptr, nullptr, &jpegR)) << "fail, API allows nullptr gainmap image";
 
+  // test metadata
+  ultrahdr_metadata_struct good_metadata;
+  good_metadata.version = "1.0";
+  good_metadata.minContentBoost = 1.0f;
+  good_metadata.maxContentBoost = 2.0f;
+  good_metadata.gamma = 1.0f;
+  good_metadata.offsetSdr = 0.0f;
+  good_metadata.offsetHdr = 0.0f;
+  good_metadata.hdrCapacityMin = 1.0f;
+  good_metadata.hdrCapacityMax = 2.0f;
+
+  ultrahdr_metadata_struct metadata = good_metadata;
+  metadata.version = "1.1";
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata version";
+
+  metadata = good_metadata;
+  metadata.minContentBoost = 3.0f;
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata content boost";
+
+  metadata = good_metadata;
+  metadata.gamma = -0.1f;
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata gamma";
+
+  metadata = good_metadata;
+  metadata.offsetSdr = -0.1f;
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata offset sdr";
+
+  metadata = good_metadata;
+  metadata.offsetHdr = -0.1f;
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata offset hdr";
+
+  metadata = good_metadata;
+  metadata.hdrCapacityMax = 0.5f;
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata hdr capacity max";
+
+  metadata = good_metadata;
+  metadata.hdrCapacityMin = 0.5f;
+  EXPECT_NE(OK, jpegRCodec.encodeJPEGR(
+      &jpegR, nullptr, &metadata, &jpegR)) << "fail, API allows bad metadata hdr capacity min";
+
   free(jpegR.data);
 }
 
@@ -864,8 +910,13 @@
 TEST_F(JpegRTest, writeXmpThenRead) {
   ultrahdr_metadata_struct metadata_expected;
   metadata_expected.version = "1.0";
-  metadata_expected.maxContentBoost = 1.25;
-  metadata_expected.minContentBoost = 0.75;
+  metadata_expected.maxContentBoost = 1.25f;
+  metadata_expected.minContentBoost = 0.75f;
+  metadata_expected.gamma = 1.0f;
+  metadata_expected.offsetSdr = 0.0f;
+  metadata_expected.offsetHdr = 0.0f;
+  metadata_expected.hdrCapacityMin = 1.0f;
+  metadata_expected.hdrCapacityMax = metadata_expected.maxContentBoost;
   const std::string nameSpace = "http://ns.adobe.com/xap/1.0/\0";
   const int nameSpaceLength = nameSpace.size() + 1;  // need to count the null terminator
 
@@ -882,6 +933,11 @@
   EXPECT_TRUE(getMetadataFromXMP(xmpData.data(), xmpData.size(), &metadata_read));
   EXPECT_FLOAT_EQ(metadata_expected.maxContentBoost, metadata_read.maxContentBoost);
   EXPECT_FLOAT_EQ(metadata_expected.minContentBoost, metadata_read.minContentBoost);
+  EXPECT_FLOAT_EQ(metadata_expected.gamma, metadata_read.gamma);
+  EXPECT_FLOAT_EQ(metadata_expected.offsetSdr, metadata_read.offsetSdr);
+  EXPECT_FLOAT_EQ(metadata_expected.offsetHdr, metadata_read.offsetHdr);
+  EXPECT_FLOAT_EQ(metadata_expected.hdrCapacityMin, metadata_read.hdrCapacityMin);
+  EXPECT_FLOAT_EQ(metadata_expected.hdrCapacityMax, metadata_read.hdrCapacityMax);
 }
 
 /* Test Encode API-0 */
@@ -1297,9 +1353,7 @@
 
   JpegRBenchmark benchmark;
 
-  ultrahdr_metadata_struct metadata = { .version = "1.0",
-                              .maxContentBoost = 8.0f,
-                              .minContentBoost = 1.0f / 8.0f };
+  ultrahdr_metadata_struct metadata = { .version = "1.0" };
 
   jpegr_uncompressed_struct map = { .data = NULL,
                                     .width = 0,