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Merged
DichenZhang1 merged 1 commit into from
Aug 19, 2026
Merged

fix(metadata): validate gainmap metadata descriptors upon decoding/pa… #449

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38 changes: 19 additions & 19 deletions lib/include/ultrahdr/gainmapmetadata.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,25 +23,25 @@ constexpr uint8_t kUseBaseColorSpaceMask = (1u << 6);
// Gain map metadata, for tone mapping between SDR and HDR.
// This is the fraction version of {@code uhdr_gainmap_metadata_ext_t}.
struct uhdr_gainmap_metadata_frac {
int32_t gainMapMinN[3];
uint32_t gainMapMinD[3];
int32_t gainMapMaxN[3];
uint32_t gainMapMaxD[3];
uint32_t gainMapGammaN[3];
uint32_t gainMapGammaD[3];

int32_t baseOffsetN[3];
uint32_t baseOffsetD[3];
int32_t alternateOffsetN[3];
uint32_t alternateOffsetD[3];

uint32_t baseHdrHeadroomN;
uint32_t baseHdrHeadroomD;
uint32_t alternateHdrHeadroomN;
uint32_t alternateHdrHeadroomD;

bool backwardDirection;
bool useBaseColorSpace;
int32_t gainMapMinN[3] = {0, 0, 0};
uint32_t gainMapMinD[3] = {1, 1, 1};
int32_t gainMapMaxN[3] = {1, 1, 1};
uint32_t gainMapMaxD[3] = {1, 1, 1};
uint32_t gainMapGammaN[3] = {1, 1, 1};
uint32_t gainMapGammaD[3] = {1, 1, 1};

int32_t baseOffsetN[3] = {0, 0, 0};
uint32_t baseOffsetD[3] = {1, 1, 1};
int32_t alternateOffsetN[3] = {0, 0, 0};
uint32_t alternateOffsetD[3] = {1, 1, 1};

uint32_t baseHdrHeadroomN = 0;
uint32_t baseHdrHeadroomD = 1;
uint32_t alternateHdrHeadroomN = 1;
uint32_t alternateHdrHeadroomD = 1;

bool backwardDirection = false;
bool useBaseColorSpace = true;

static uhdr_error_info_t encodeGainmapMetadata(const uhdr_gainmap_metadata_frac* in_metadata,
std::vector<uint8_t>& out_data);
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3 changes: 2 additions & 1 deletion lib/src/gainmapmetadata.cpp
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Expand Up @@ -13,6 +13,7 @@

#include "ultrahdr/gainmapmath.h"
#include "ultrahdr/gainmapmetadata.h"
#include "ultrahdr/ultrahdrcommon.h"

namespace ultrahdr {

Expand Down Expand Up @@ -342,7 +343,7 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(
to->hdr_capacity_min = exp2((float)from->baseHdrHeadroomN / from->baseHdrHeadroomD);
to->use_base_cg = from->useBaseColorSpace;

return g_no_error;
return uhdr_validate_gainmap_metadata_descriptor(to);
}

uhdr_error_info_t uhdr_gainmap_metadata_frac::gainmapMetadataFloatToFraction(
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2 changes: 1 addition & 1 deletion lib/src/jpegrutils.cpp
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Expand Up @@ -870,7 +870,7 @@ uhdr_error_info_t getMetadataFromXMP(uint8_t* xmp_data, size_t xmp_size, uint8_t
std::fill_n(metadata->offset_hdr + 1, 2, metadata->offset_hdr[0]);
std::fill_n(metadata->offset_sdr + 1, 2, metadata->offset_sdr[0]);

return g_no_error;
return uhdr_validate_gainmap_metadata_descriptor(metadata);
}

string generateXmpForPrimaryImage(size_t secondary_image_length,
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23 changes: 12 additions & 11 deletions lib/src/ultrahdr_api.cpp
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Expand Up @@ -1721,17 +1721,18 @@ uhdr_error_info_t uhdr_dec_probe(uhdr_codec_private_t* dec) {
ultrahdr::uhdr_gainmap_metadata_frac frac;
if (ultrahdr::uhdr_gainmap_metadata_frac::decodeGainmapMetadata(meta, &frac).error_code == UHDR_CODEC_OK) {
ultrahdr::uhdr_gainmap_metadata_ext_t metadata;
ultrahdr::uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(&frac, &metadata);
std::copy(metadata.max_content_boost, metadata.max_content_boost + 3,
handle->m_metadata.max_content_boost);
std::copy(metadata.min_content_boost, metadata.min_content_boost + 3,
handle->m_metadata.min_content_boost);
std::copy(metadata.gamma, metadata.gamma + 3, handle->m_metadata.gamma);
std::copy(metadata.offset_sdr, metadata.offset_sdr + 3, handle->m_metadata.offset_sdr);
std::copy(metadata.offset_hdr, metadata.offset_hdr + 3, handle->m_metadata.offset_hdr);
handle->m_metadata.hdr_capacity_min = metadata.hdr_capacity_min;
handle->m_metadata.hdr_capacity_max = metadata.hdr_capacity_max;
handle->m_metadata.use_base_cg = metadata.use_base_cg;
if (ultrahdr::uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(&frac, &metadata).error_code == UHDR_CODEC_OK) {
std::copy(metadata.max_content_boost, metadata.max_content_boost + 3,
handle->m_metadata.max_content_boost);
std::copy(metadata.min_content_boost, metadata.min_content_boost + 3,
handle->m_metadata.min_content_boost);
std::copy(metadata.gamma, metadata.gamma + 3, handle->m_metadata.gamma);
std::copy(metadata.offset_sdr, metadata.offset_sdr + 3, handle->m_metadata.offset_sdr);
std::copy(metadata.offset_hdr, metadata.offset_hdr + 3, handle->m_metadata.offset_hdr);
handle->m_metadata.hdr_capacity_min = metadata.hdr_capacity_min;
handle->m_metadata.hdr_capacity_max = metadata.hdr_capacity_max;
handle->m_metadata.use_base_cg = metadata.use_base_cg;
}
}
}
heif_image_handle_release(gainmap_handle);
Expand Down
39 changes: 37 additions & 2 deletions tests/gainmapmetadata_test.cpp
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Expand Up @@ -82,8 +82,8 @@ TEST_F(GainMapMetadataTest, encodeMetadataThenDecode) {
data.clear();
for (int i = 0; i < 3; i++) {
expected.min_content_boost[i] = 0.000578369f + i * 0.001f;
expected.offset_sdr[i] = -0.0625f + i * 0.001f;
expected.offset_hdr[i] = -0.0625f + i * 0.001f;
expected.offset_sdr[i] = 0.0625f + i * 0.001f;
expected.offset_hdr[i] = 0.0625f + i * 0.001f;
}
expected.hdr_capacity_max = 1000.0f / 203.0f;
expected.use_base_cg = true;
Expand Down Expand Up @@ -112,4 +112,39 @@ TEST_F(GainMapMetadataTest, encodeMetadataThenDecode) {
EXPECT_EQ(expected.use_base_cg, decodedUHdrMetadata.use_base_cg);
}

TEST(GainmapMetadataTest, RejectsMalformedISO21496_1Ratios) {
uhdr_gainmap_metadata_frac frac{};
for (int i = 0; i < 3; ++i) {
frac.gainMapMaxN[i] = 1;
frac.gainMapMaxD[i] = 1;
frac.gainMapMinN[i] = 0;
frac.gainMapMinD[i] = 1;
frac.gainMapGammaN[i] = 1;
frac.gainMapGammaD[i] = 1;
frac.baseOffsetN[i] = 0;
frac.baseOffsetD[i] = 1;
frac.alternateOffsetN[i] = 0;
frac.alternateOffsetD[i] = 1;
}
frac.baseHdrHeadroomN = 0;
frac.baseHdrHeadroomD = 1;
frac.alternateHdrHeadroomN = 1;
frac.alternateHdrHeadroomD = 1;

// Test 1: max_content_boost < min_content_boost
frac.gainMapMaxN[0] = 0; // log2(max_boost) = 0 -> max_boost = 1.0
frac.gainMapMinN[0] = 2; // log2(min_boost) = 2 -> min_boost = 4.0
uhdr_gainmap_metadata_ext_t float_meta;
EXPECT_EQ(uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(&frac, &float_meta).error_code,
UHDR_CODEC_INVALID_PARAM);

// Test 2: Inverted HDR capacity range (max <= min)
frac.gainMapMaxN[0] = 1;
frac.gainMapMinN[0] = 0;
frac.alternateHdrHeadroomN = 0; // log2(headroom_max) = 0 -> 1.0
frac.baseHdrHeadroomN = 1; // log2(headroom_min) = 1 -> 2.0
EXPECT_EQ(uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(&frac, &float_meta).error_code,
UHDR_CODEC_INVALID_PARAM);
}

} // namespace ultrahdr
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