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Preserve alpha in raw AVIF and HEIF encoding #455

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15 changes: 11 additions & 4 deletions lib/include/ultrahdr/avifultrahdr.h
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Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,7 @@ class AvifUltraHdr : public UltraHdr {
* sdr intent. sdr intent and gain map coefficient are compressed using heif/avif encoding.
* compressed sdr intent is signalled as primary item and compressed gainmap is signalled as a
* tone map derived item
* NOTE: Alpha is preserved as straight 8-bit alpha when hdr intent uses an RGBA pixel format.
*
* \param[in] hdr_intent hdr intent raw input image descriptor
* \param[in, out] dest output image descriptor to store compressed ultrahdr image
Expand All @@ -79,6 +80,7 @@ class AvifUltraHdr : public UltraHdr {
* coefficient are compressed using heif/avif encoding. compressed sdr intent is signalled as
* primary item and compressed gainmap is signalled as a tone map derived item
* NOTE: Color transfer of sdr intent is expected to be sRGB.
* NOTE: Alpha is preserved as straight 8-bit alpha when sdr intent uses an RGBA pixel format.
*
* \param[in] hdr_intent hdr intent raw input image descriptor
* \param[in] sdr_intent sdr intent raw input image descriptor
Expand Down Expand Up @@ -147,6 +149,8 @@ class AvifUltraHdr : public UltraHdr {
* primary item and compressed gainmap is signalled as a tone map derived item
*
* \param[in] sdr_intent sdr intent raw input image descriptor
* \param[in] base_alpha_source optional raw RGBA image whose alpha is encoded as straight
* 8-bit alpha in the base image
* \param[in] gainmap_img gainmap raw image descriptor
* \param[in] metadata gainmap metadata descriptor
* \param[in, out] dest output image descriptor to store compressed ultrahdr image
Expand All @@ -158,10 +162,13 @@ class AvifUltraHdr : public UltraHdr {
*
* \return uhdr_error_info_t #UHDR_CODEC_OK if operation succeeds, uhdr_codec_err_t otherwise.
*/
uhdr_error_info_t encodeAvifUltraHdr(uhdr_raw_image_t* sdr_intent, uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality, uhdr_mem_block_t* exif,
DataStruct* baseIcc, DataStruct* alternateIcc);
uhdr_error_info_t encodeAvifUltraHdr(uhdr_raw_image_t* sdr_intent,
uhdr_raw_image_t* base_alpha_source,
uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality,
uhdr_mem_block_t* exif, DataStruct* baseIcc,
DataStruct* alternateIcc);

uhdr_codec_t mCodec;
};
Expand Down
15 changes: 11 additions & 4 deletions lib/include/ultrahdr/heifultrahdr.h
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Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,7 @@ class HeifUltraHdr : public UltraHdr {
* sdr intent. sdr intent and gain map coefficient are compressed using heif/avif encoding.
* compressed sdr intent is signalled as primary item and compressed gainmap is signalled as a
* tone map derived item
* NOTE: Alpha is preserved as straight 8-bit alpha when hdr intent uses an RGBA pixel format.
*
* \param[in] hdr_intent hdr intent raw input image descriptor
* \param[in, out] dest output image descriptor to store compressed ultrahdr image
Expand All @@ -79,6 +80,7 @@ class HeifUltraHdr : public UltraHdr {
* coefficient are compressed using heif/avif encoding. compressed sdr intent is signalled as
* primary item and compressed gainmap is signalled as a tone map derived item
* NOTE: Color transfer of sdr intent is expected to be sRGB.
* NOTE: Alpha is preserved as straight 8-bit alpha when sdr intent uses an RGBA pixel format.
*
* \param[in] hdr_intent hdr intent raw input image descriptor
* \param[in] sdr_intent sdr intent raw input image descriptor
Expand Down Expand Up @@ -147,6 +149,8 @@ class HeifUltraHdr : public UltraHdr {
* primary item and compressed gainmap is signalled as a tone map derived item
*
* \param[in] sdr_intent sdr intent raw input image descriptor
* \param[in] base_alpha_source optional raw RGBA image whose alpha is encoded as straight
* 8-bit alpha in the base image
* \param[in] gainmap_img gainmap raw image descriptor
* \param[in] metadata gainmap metadata descriptor
* \param[in, out] dest output image descriptor to store compressed ultrahdr image
Expand All @@ -158,10 +162,13 @@ class HeifUltraHdr : public UltraHdr {
*
* \return uhdr_error_info_t #UHDR_CODEC_OK if operation succeeds, uhdr_codec_err_t otherwise.
*/
uhdr_error_info_t encodeHeicUltraHdr(uhdr_raw_image_t* sdr_intent, uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality, uhdr_mem_block_t* exif,
DataStruct* baseIcc, DataStruct* alternateIcc);
uhdr_error_info_t encodeHeicUltraHdr(uhdr_raw_image_t* sdr_intent,
uhdr_raw_image_t* base_alpha_source,
uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality,
uhdr_mem_block_t* exif, DataStruct* baseIcc,
DataStruct* alternateIcc);

uhdr_codec_t mCodec;
};
Expand Down
77 changes: 68 additions & 9 deletions lib/src/avifultrahdr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@

#ifdef UHDR_ENABLE_HEIF

#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <map>

Expand Down Expand Up @@ -85,6 +87,59 @@ static struct heif_error fill_img_plane(heif_image* img, heif_channel channel, v
return err;
}

static uint8_t get_alpha_value(const uhdr_raw_image_t* image, size_t x, size_t y) {
if (image->fmt == UHDR_IMG_FMT_32bppRGBA8888) {
const auto* row = static_cast<const uint32_t*>(image->planes[UHDR_PLANE_PACKED]) +
y * image->stride[UHDR_PLANE_PACKED];
return static_cast<uint8_t>(row[x] >> 24);
}
if (image->fmt == UHDR_IMG_FMT_32bppRGBA1010102) {
const auto* row = static_cast<const uint32_t*>(image->planes[UHDR_PLANE_PACKED]) +
y * image->stride[UHDR_PLANE_PACKED];
return static_cast<uint8_t>(((row[x] >> 30) & 0x3u) * 85u);
}
const auto* row = static_cast<const uint16_t*>(image->planes[UHDR_PLANE_PACKED]) +
y * image->stride[UHDR_PLANE_PACKED] * 4;
float alpha = halfToFloat(row[x * 4 + 3]);
if (std::isnan(alpha)) alpha = 0.0f;
alpha = std::clamp(alpha, 0.0f, 1.0f);
return static_cast<uint8_t>(alpha * 255.0f + 0.5f);
}

static struct heif_error add_alpha_plane(heif_image* image, const uhdr_raw_image_t* alpha_source) {
if (alpha_source == nullptr || (alpha_source->fmt != UHDR_IMG_FMT_32bppRGBA8888 &&
alpha_source->fmt != UHDR_IMG_FMT_32bppRGBA1010102 &&
alpha_source->fmt != UHDR_IMG_FMT_64bppRGBAHalfFloat)) {
return {heif_error_Ok, heif_suberror_Unspecified, nullptr};
}

bool has_transparency = false;
for (size_t y = 0; y < alpha_source->h && !has_transparency; ++y) {
for (size_t x = 0; x < alpha_source->w; ++x) {
if (get_alpha_value(alpha_source, x, y) != 255) {
has_transparency = true;
break;
}
}
}
if (!has_transparency) return {heif_error_Ok, heif_suberror_Unspecified, nullptr};

heif_error err =
heif_image_add_plane(image, heif_channel_Alpha, alpha_source->w, alpha_source->h, 8);
if (err.code != heif_error_Ok) return err;

int dst_stride;
uint8_t* dst = heif_image_get_plane(image, heif_channel_Alpha, &dst_stride);
for (size_t y = 0; y < alpha_source->h; ++y) {
for (size_t x = 0; x < alpha_source->w; ++x) {
dst[x] = get_alpha_value(alpha_source, x, y);
}
dst += dst_stride;
}
heif_image_set_premultiplied_alpha(image, 0);
return err;
}

static struct heif_error copy_img_plane(heif_image* img, heif_channel channel, void* dstBuffer,
int width, int height, int dstRowStride, int bpp) {
if (channel != heif_channel_interleaved && channel != heif_channel_Y &&
Expand Down Expand Up @@ -324,8 +379,8 @@ uhdr_error_info_t AvifUltraHdr::encodeAvifUltraHdr(uhdr_raw_image_t* hdr_intent,
std::shared_ptr<DataStruct> alternateIcc =
IccHelper::writeIccProfile(gainmap->ct, gainmap->cg);

return encodeAvifUltraHdr(sdr_intent_yuv, gainmap.get(), &metadata, dest, quality, exif, baseIcc.get(),
alternateIcc.get());
return encodeAvifUltraHdr(sdr_intent_yuv, hdr_intent, gainmap.get(), &metadata, dest, quality,
exif, baseIcc.get(), alternateIcc.get());
}

/* Encode API-1 */
Expand Down Expand Up @@ -353,15 +408,17 @@ uhdr_error_info_t AvifUltraHdr::encodeAvifUltraHdr(uhdr_raw_image_t* hdr_intent,
std::shared_ptr<DataStruct> alternateIcc =
IccHelper::writeIccProfile(gainmap->ct, gainmap->cg);

return encodeAvifUltraHdr(sdr_intent_yuv, gainmap.get(), &metadata, dest, quality, exif, baseIcc.get(),
alternateIcc.get());
return encodeAvifUltraHdr(sdr_intent_yuv, sdr_intent, gainmap.get(), &metadata, dest, quality,
exif, baseIcc.get(), alternateIcc.get());
}

uhdr_error_info_t AvifUltraHdr::encodeAvifUltraHdr(uhdr_raw_image_t* sdr_intent, uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality,
uhdr_mem_block_t* exif, DataStruct* baseIcc,
DataStruct* alternateIcc) {
uhdr_error_info_t AvifUltraHdr::encodeAvifUltraHdr(uhdr_raw_image_t* sdr_intent,
uhdr_raw_image_t* base_alpha_source,
uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality,
uhdr_mem_block_t* exif, DataStruct* baseIcc,
DataStruct* alternateIcc) {
uhdr_error_info_t status = g_no_error;
heif_encoder* encoder = nullptr;
heif_encoding_options* options = nullptr;
Expand Down Expand Up @@ -411,6 +468,7 @@ uhdr_error_info_t AvifUltraHdr::encodeAvifUltraHdr(uhdr_raw_image_t* sdr_intent,
chromaWd, chromaHt, sdr_intent->stride[UHDR_PLANE_U]));
HEIF_ERR_CHECK(fill_img_plane(baseImage, heif_channel_Cr, sdr_intent->planes[UHDR_PLANE_V],
chromaWd, chromaHt, sdr_intent->stride[UHDR_PLANE_V]));
HEIF_ERR_CHECK(add_alpha_plane(baseImage, base_alpha_source));
if (baseIcc != nullptr) {
void* ptr = (uint8_t*)baseIcc->getData() + kICCIdentifierSize;
HEIF_ERR_CHECK(heif_image_set_raw_color_profile(baseImage, "prof", ptr,
Expand Down Expand Up @@ -442,6 +500,7 @@ uhdr_error_info_t AvifUltraHdr::encodeAvifUltraHdr(uhdr_raw_image_t* sdr_intent,
goto CleanUp;
}
options->save_two_colr_boxes_when_ICC_and_nclx_available = 1;
options->save_alpha_channel = 1;
options->output_nclx_profile = sdrNclx;
HEIF_ERR_CHECK(heif_image_set_nclx_color_profile(baseImage, sdrNclx));
HEIF_ERR_CHECK(heif_context_encode_image(ctx, baseImage, encoder, options, &baseHandle));
Expand Down
77 changes: 68 additions & 9 deletions lib/src/heifultrahdr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@

#ifdef UHDR_ENABLE_HEIF

#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <map>

Expand Down Expand Up @@ -85,6 +87,59 @@ static struct heif_error fill_img_plane(heif_image* img, heif_channel channel, v
return err;
}

static uint8_t get_alpha_value(const uhdr_raw_image_t* image, size_t x, size_t y) {
if (image->fmt == UHDR_IMG_FMT_32bppRGBA8888) {
const auto* row = static_cast<const uint32_t*>(image->planes[UHDR_PLANE_PACKED]) +
y * image->stride[UHDR_PLANE_PACKED];
return static_cast<uint8_t>(row[x] >> 24);
}
if (image->fmt == UHDR_IMG_FMT_32bppRGBA1010102) {
const auto* row = static_cast<const uint32_t*>(image->planes[UHDR_PLANE_PACKED]) +
y * image->stride[UHDR_PLANE_PACKED];
return static_cast<uint8_t>(((row[x] >> 30) & 0x3u) * 85u);
}
const auto* row = static_cast<const uint16_t*>(image->planes[UHDR_PLANE_PACKED]) +
y * image->stride[UHDR_PLANE_PACKED] * 4;
float alpha = halfToFloat(row[x * 4 + 3]);
if (std::isnan(alpha)) alpha = 0.0f;
alpha = std::clamp(alpha, 0.0f, 1.0f);
return static_cast<uint8_t>(alpha * 255.0f + 0.5f);
}

static struct heif_error add_alpha_plane(heif_image* image, const uhdr_raw_image_t* alpha_source) {
if (alpha_source == nullptr || (alpha_source->fmt != UHDR_IMG_FMT_32bppRGBA8888 &&
alpha_source->fmt != UHDR_IMG_FMT_32bppRGBA1010102 &&
alpha_source->fmt != UHDR_IMG_FMT_64bppRGBAHalfFloat)) {
return {heif_error_Ok, heif_suberror_Unspecified, nullptr};
}

bool has_transparency = false;
for (size_t y = 0; y < alpha_source->h && !has_transparency; ++y) {
for (size_t x = 0; x < alpha_source->w; ++x) {
if (get_alpha_value(alpha_source, x, y) != 255) {
has_transparency = true;
break;
}
}
}
if (!has_transparency) return {heif_error_Ok, heif_suberror_Unspecified, nullptr};

heif_error err =
heif_image_add_plane(image, heif_channel_Alpha, alpha_source->w, alpha_source->h, 8);
if (err.code != heif_error_Ok) return err;

int dst_stride;
uint8_t* dst = heif_image_get_plane(image, heif_channel_Alpha, &dst_stride);
for (size_t y = 0; y < alpha_source->h; ++y) {
for (size_t x = 0; x < alpha_source->w; ++x) {
dst[x] = get_alpha_value(alpha_source, x, y);
}
dst += dst_stride;
}
heif_image_set_premultiplied_alpha(image, 0);
return err;
}

static struct heif_error copy_img_plane(heif_image* img, heif_channel channel, void* dstBuffer,
int width, int height, int dstRowStride, int bpp) {
if (channel != heif_channel_interleaved && channel != heif_channel_Y &&
Expand Down Expand Up @@ -324,8 +379,8 @@ uhdr_error_info_t HeifUltraHdr::encodeHeicUltraHdr(uhdr_raw_image_t* hdr_intent,
std::shared_ptr<DataStruct> alternateIcc =
IccHelper::writeIccProfile(gainmap->ct, gainmap->cg);

return encodeHeicUltraHdr(sdr_intent_yuv, gainmap.get(), &metadata, dest, quality, exif, baseIcc.get(),
alternateIcc.get());
return encodeHeicUltraHdr(sdr_intent_yuv, hdr_intent, gainmap.get(), &metadata, dest, quality,
exif, baseIcc.get(), alternateIcc.get());
}

/* Encode API-1 */
Expand Down Expand Up @@ -353,15 +408,17 @@ uhdr_error_info_t HeifUltraHdr::encodeHeicUltraHdr(uhdr_raw_image_t* hdr_intent,
std::shared_ptr<DataStruct> alternateIcc =
IccHelper::writeIccProfile(gainmap->ct, gainmap->cg);

return encodeHeicUltraHdr(sdr_intent_yuv, gainmap.get(), &metadata, dest, quality, exif, baseIcc.get(),
alternateIcc.get());
return encodeHeicUltraHdr(sdr_intent_yuv, sdr_intent, gainmap.get(), &metadata, dest, quality,
exif, baseIcc.get(), alternateIcc.get());
}

uhdr_error_info_t HeifUltraHdr::encodeHeicUltraHdr(uhdr_raw_image_t* sdr_intent, uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality,
uhdr_mem_block_t* exif, DataStruct* baseIcc,
DataStruct* alternateIcc) {
uhdr_error_info_t HeifUltraHdr::encodeHeicUltraHdr(uhdr_raw_image_t* sdr_intent,
uhdr_raw_image_t* base_alpha_source,
uhdr_raw_image_t* gainmap_img,
uhdr_gainmap_metadata_ext_t* metadata,
uhdr_compressed_image_t* dest, int quality,
uhdr_mem_block_t* exif, DataStruct* baseIcc,
DataStruct* alternateIcc) {
uhdr_error_info_t status = g_no_error;
heif_encoder* encoder = nullptr;
heif_encoding_options* options = nullptr;
Expand Down Expand Up @@ -411,6 +468,7 @@ uhdr_error_info_t HeifUltraHdr::encodeHeicUltraHdr(uhdr_raw_image_t* sdr_intent,
chromaWd, chromaHt, sdr_intent->stride[UHDR_PLANE_U]));
HEIF_ERR_CHECK(fill_img_plane(baseImage, heif_channel_Cr, sdr_intent->planes[UHDR_PLANE_V],
chromaWd, chromaHt, sdr_intent->stride[UHDR_PLANE_V]));
HEIF_ERR_CHECK(add_alpha_plane(baseImage, base_alpha_source));
if (baseIcc != nullptr) {
void* ptr = (uint8_t*)baseIcc->getData() + kICCIdentifierSize;
HEIF_ERR_CHECK(heif_image_set_raw_color_profile(baseImage, "prof", ptr,
Expand Down Expand Up @@ -442,6 +500,7 @@ uhdr_error_info_t HeifUltraHdr::encodeHeicUltraHdr(uhdr_raw_image_t* sdr_intent,
goto CleanUp;
}
options->save_two_colr_boxes_when_ICC_and_nclx_available = 1;
options->save_alpha_channel = 1;
options->output_nclx_profile = sdrNclx;
HEIF_ERR_CHECK(heif_image_set_nclx_color_profile(baseImage, sdrNclx));
HEIF_ERR_CHECK(heif_context_encode_image(ctx, baseImage, encoder, options, &baseHandle));
Expand Down
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