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Update ISO 21496-1 Metadata (google#314)
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* Update ISO 21496-1 Metadata

* Update gainmapmetadata_test.cpp
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@DichenZhang1
DichenZhang1 authored Nov 1, 2024
1 parent 990f103 commit 25e4c8e
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Showing 3 changed files with 56 additions and 26 deletions.
2 changes: 2 additions & 0 deletions lib/include/ultrahdr/gainmapmetadata.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,8 @@
#include <vector>

namespace ultrahdr {
constexpr uint8_t kIsMultiChannelMask = (1u << 7);
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}.
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66 changes: 47 additions & 19 deletions lib/src/gainmapmetadata.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,13 +14,21 @@
* limitations under the License.
*/

#include <algorithm>
#include <cmath>

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

namespace ultrahdr {

void streamWriteU8(std::vector<uint8_t> &data, uint8_t value) { data.push_back(value); }

void streamWriteU16(std::vector<uint8_t> &data, uint16_t value) {
data.push_back((value >> 8) & 0xff);
data.push_back(value & 0xff);
}

void streamWriteU32(std::vector<uint8_t> &data, uint32_t value) {
data.push_back((value >> 24) & 0xff);
data.push_back((value >> 16) & 0xff);
Expand All @@ -42,6 +50,21 @@ uhdr_error_info_t streamReadU8(const std::vector<uint8_t> &data, uint8_t &value,
return g_no_error;
}

uhdr_error_info_t streamReadU16(const std::vector<uint8_t> &data, uint16_t &value, size_t &pos) {
if (pos + 1 >= data.size()) {
uhdr_error_info_t status;
status.error_code = UHDR_CODEC_MEM_ERROR;
status.has_detail = 1;
snprintf(status.detail, sizeof status.detail,
"attempting to read 2 bytes from position %d when the buffer size is %d", (int)pos,
(int)data.size());
return status;
}
value = (data[pos] << 8 | data[pos + 1]);
pos += 2;
return g_no_error;
}

uhdr_error_info_t streamReadU32(const std::vector<uint8_t> &data, uint32_t &value, size_t &pos) {
if (pos + 3 >= data.size()) {
uhdr_error_info_t status;
Expand All @@ -68,8 +91,9 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::encodeGainmapMetadata(
return status;
}

const uint8_t version = 0;
streamWriteU8(out_data, version);
const uint16_t min_version = 0, writer_version = 0;
streamWriteU16(out_data, min_version);
streamWriteU16(out_data, writer_version);

uint8_t flags = 0u;
// Always write three channels for now for simplicity.
Expand Down Expand Up @@ -100,10 +124,10 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::encodeGainmapMetadata(
const uint8_t channelCount = allChannelsIdentical ? 1u : 3u;

if (channelCount == 3) {
flags |= 1;
flags |= kIsMultiChannelMask;
}
if (in_metadata->useBaseColorSpace) {
flags |= 2;
flags |= kUseBaseColorSpaceMask;
}
if (in_metadata->backwardDirection) {
flags |= 4;
Expand Down Expand Up @@ -171,20 +195,22 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::decodeGainmapMetadata(
}

size_t pos = 0;
uint8_t version = 0xff;
UHDR_ERR_CHECK(streamReadU8(in_data, version, pos))
if (version != 0) {
uint16_t min_version = 0xffff;
uint16_t writer_version = 0xffff;
UHDR_ERR_CHECK(streamReadU16(in_data, min_version, pos))
if (min_version != 0) {
uhdr_error_info_t status;
status.error_code = UHDR_CODEC_UNSUPPORTED_FEATURE;
status.has_detail = 1;
snprintf(status.detail, sizeof status.detail, "received unexpected version %d, expected 0",
version);
snprintf(status.detail, sizeof status.detail, "received unexpected minimum version %d, expected 0",
min_version);
return status;
}
UHDR_ERR_CHECK(streamReadU16(in_data, writer_version, pos))

uint8_t flags = 0xff;
UHDR_ERR_CHECK(streamReadU8(in_data, flags, pos))
uint8_t channelCount = (flags & 1) * 2 + 1;
uint8_t channelCount = (flags & kIsMultiChannelMask) * 2 + 1;
if (!(channelCount == 1 || channelCount == 3)) {
uhdr_error_info_t status;
status.error_code = UHDR_CODEC_UNSUPPORTED_FEATURE;
Expand All @@ -193,7 +219,7 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::decodeGainmapMetadata(
"received unexpected channel count %d, expects one of {1, 3}", channelCount);
return status;
}
out_metadata->useBaseColorSpace = (flags & 2) != 0;
out_metadata->useBaseColorSpace = (flags & kUseBaseColorSpaceMask) != 0;
out_metadata->backwardDirection = (flags & 4) != 0;
const bool useCommonDenominator = (flags & 8) != 0;

Expand Down Expand Up @@ -283,16 +309,18 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(
UHDR_CHECK_NON_ZERO(from->baseOffsetD[i], "baseOffset denominator");
UHDR_CHECK_NON_ZERO(from->alternateOffsetD[i], "alternateOffset denominator");
}

to->version = kJpegrVersion;
to->max_content_boost = (float)from->gainMapMaxN[0] / from->gainMapMaxD[0];
to->min_content_boost = (float)from->gainMapMinN[0] / from->gainMapMinD[0];
to->max_content_boost = exp2((float)from->gainMapMaxN[0] / from->gainMapMaxD[0]);
to->min_content_boost = exp2((float)from->gainMapMinN[0] / from->gainMapMinD[0]);

to->gamma = (float)from->gainMapGammaN[0] / from->gainMapGammaD[0];

// BaseRenditionIsHDR is false
to->offset_sdr = (float)from->baseOffsetN[0] / from->baseOffsetD[0];
to->offset_hdr = (float)from->alternateOffsetN[0] / from->alternateOffsetD[0];
to->hdr_capacity_max = (float)from->alternateHdrHeadroomN / from->alternateHdrHeadroomD;
to->hdr_capacity_min = (float)from->baseHdrHeadroomN / from->baseHdrHeadroomD;
to->hdr_capacity_max = exp2((float)from->alternateHdrHeadroomN / from->alternateHdrHeadroomD);
to->hdr_capacity_min = exp2((float)from->baseHdrHeadroomN / from->baseHdrHeadroomD);

return g_no_error;
}
Expand Down Expand Up @@ -322,12 +350,12 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::gainmapMetadataFloatToFraction(
return status; \
}

CONVERT_FLT_TO_UNSIGNED_FRACTION(from->max_content_boost, &to->gainMapMaxN[0],
CONVERT_FLT_TO_UNSIGNED_FRACTION(log2(from->max_content_boost), &to->gainMapMaxN[0],
&to->gainMapMaxD[0])
to->gainMapMaxN[2] = to->gainMapMaxN[1] = to->gainMapMaxN[0];
to->gainMapMaxD[2] = to->gainMapMaxD[1] = to->gainMapMaxD[0];

CONVERT_FLT_TO_UNSIGNED_FRACTION(from->min_content_boost, &to->gainMapMinN[0],
CONVERT_FLT_TO_UNSIGNED_FRACTION(log2(from->min_content_boost), &to->gainMapMinN[0],
&to->gainMapMinD[0]);
to->gainMapMinN[2] = to->gainMapMinN[1] = to->gainMapMinN[0];
to->gainMapMinD[2] = to->gainMapMinD[1] = to->gainMapMinD[0];
Expand All @@ -345,10 +373,10 @@ uhdr_error_info_t uhdr_gainmap_metadata_frac::gainmapMetadataFloatToFraction(
to->alternateOffsetN[2] = to->alternateOffsetN[1] = to->alternateOffsetN[0];
to->alternateOffsetD[2] = to->alternateOffsetD[1] = to->alternateOffsetD[0];

CONVERT_FLT_TO_UNSIGNED_FRACTION(from->hdr_capacity_min, &to->baseHdrHeadroomN,
CONVERT_FLT_TO_UNSIGNED_FRACTION(log2(from->hdr_capacity_min), &to->baseHdrHeadroomN,
&to->baseHdrHeadroomD);

CONVERT_FLT_TO_UNSIGNED_FRACTION(from->hdr_capacity_max, &to->alternateHdrHeadroomN,
CONVERT_FLT_TO_UNSIGNED_FRACTION(log2(from->hdr_capacity_max), &to->alternateHdrHeadroomN,
&to->alternateHdrHeadroomD);

return g_no_error;
Expand Down
14 changes: 7 additions & 7 deletions tests/gainmapmetadata_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -65,12 +65,12 @@ TEST_F(GainMapMetadataTest, encodeMetadataThenDecode) {
uhdr_gainmap_metadata_frac::gainmapMetadataFractionToFloat(&decodedMetadata,
&decodedUHdrMetadata);

EXPECT_EQ(expected.max_content_boost, decodedUHdrMetadata.max_content_boost);
EXPECT_EQ(expected.min_content_boost, decodedUHdrMetadata.min_content_boost);
EXPECT_EQ(expected.gamma, decodedUHdrMetadata.gamma);
EXPECT_EQ(expected.offset_sdr, decodedUHdrMetadata.offset_sdr);
EXPECT_EQ(expected.offset_hdr, decodedUHdrMetadata.offset_hdr);
EXPECT_EQ(expected.hdr_capacity_min, decodedUHdrMetadata.hdr_capacity_min);
EXPECT_EQ(expected.hdr_capacity_max, decodedUHdrMetadata.hdr_capacity_max);
EXPECT_FLOAT_EQ(expected.max_content_boost, decodedUHdrMetadata.max_content_boost);
EXPECT_FLOAT_EQ(expected.min_content_boost, decodedUHdrMetadata.min_content_boost);
EXPECT_FLOAT_EQ(expected.gamma, decodedUHdrMetadata.gamma);
EXPECT_FLOAT_EQ(expected.offset_sdr, decodedUHdrMetadata.offset_sdr);
EXPECT_FLOAT_EQ(expected.offset_hdr, decodedUHdrMetadata.offset_hdr);
EXPECT_FLOAT_EQ(expected.hdr_capacity_min, decodedUHdrMetadata.hdr_capacity_min);
EXPECT_FLOAT_EQ(expected.hdr_capacity_max, decodedUHdrMetadata.hdr_capacity_max);
}
} // namespace ultrahdr

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