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aomedia / libavif / 084eac1aaf30000c30bd733caf1046a652102620 / . / src / reformat.c
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// Copyright 2019 Joe Drago. All rights reserved.
// SPDX-License-Identifier: BSD-2-Clause
#include "avif/internal.h"
#include <assert.h>
#include <stdint.h>
#include <string.h>
#if defined(_WIN32)
#include <process.h>
#include <windows.h>
#else
#include <pthread.h>
#endif
struct YUVBlock
{
float y;
float u;
float v;
};
avifBool avifGetRGBColorSpaceInfo(const avifRGBImage * rgb, avifRGBColorSpaceInfo * info)
{
AVIF_CHECK(rgb->depth == 8 || rgb->depth == 10 || rgb->depth == 12 || rgb->depth == 16);
if (rgb->isFloat) {
AVIF_CHECK(rgb->depth == 16);
}
if (rgb->format == AVIF_RGB_FORMAT_RGB_565) {
AVIF_CHECK(rgb->depth == 8);
}
// Cast to silence "comparison of unsigned expression is always true" warning.
AVIF_CHECK((int)rgb->format >= AVIF_RGB_FORMAT_RGB && rgb->format < AVIF_RGB_FORMAT_COUNT);
info->channelBytes = (rgb->depth > 8) ? 2 : 1;
info->pixelBytes = avifRGBImagePixelSize(rgb);
switch (rgb->format) {
case AVIF_RGB_FORMAT_RGB:
info->offsetBytesR = info->channelBytes * 0;
info->offsetBytesG = info->channelBytes * 1;
info->offsetBytesB = info->channelBytes * 2;
info->offsetBytesA = 0;
break;
case AVIF_RGB_FORMAT_RGBA:
info->offsetBytesR = info->channelBytes * 0;
info->offsetBytesG = info->channelBytes * 1;
info->offsetBytesB = info->channelBytes * 2;
info->offsetBytesA = info->channelBytes * 3;
break;
case AVIF_RGB_FORMAT_ARGB:
info->offsetBytesA = info->channelBytes * 0;
info->offsetBytesR = info->channelBytes * 1;
info->offsetBytesG = info->channelBytes * 2;
info->offsetBytesB = info->channelBytes * 3;
break;
case AVIF_RGB_FORMAT_BGR:
info->offsetBytesB = info->channelBytes * 0;
info->offsetBytesG = info->channelBytes * 1;
info->offsetBytesR = info->channelBytes * 2;
info->offsetBytesA = 0;
break;
case AVIF_RGB_FORMAT_BGRA:
info->offsetBytesB = info->channelBytes * 0;
info->offsetBytesG = info->channelBytes * 1;
info->offsetBytesR = info->channelBytes * 2;
info->offsetBytesA = info->channelBytes * 3;
break;
case AVIF_RGB_FORMAT_ABGR:
info->offsetBytesA = info->channelBytes * 0;
info->offsetBytesB = info->channelBytes * 1;
info->offsetBytesG = info->channelBytes * 2;
info->offsetBytesR = info->channelBytes * 3;
break;
case AVIF_RGB_FORMAT_RGB_565:
// Since RGB_565 consists of two bytes per RGB pixel, we simply use
// the pointer to the red channel to populate the entire pixel value
// as a uint16_t. As a result only offsetBytesR is used and the
// other offsets are unused.
info->offsetBytesR = 0;
info->offsetBytesG = 0;
info->offsetBytesB = 0;
info->offsetBytesA = 0;
break;
case AVIF_RGB_FORMAT_COUNT:
return AVIF_FALSE;
}
info->maxChannel = (1 << rgb->depth) - 1;
info->maxChannelF = (float)info->maxChannel;
return AVIF_TRUE;
}
avifBool avifGetYUVColorSpaceInfo(const avifImage * image, avifYUVColorSpaceInfo * info)
{
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
const avifBool useYCgCo = (image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RE) ||
(image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RO);
#endif
AVIF_CHECK(image->depth == 8 || image->depth == 10 || image->depth == 12 || image->depth == 16);
AVIF_CHECK(image->yuvFormat >= AVIF_PIXEL_FORMAT_YUV444 && image->yuvFormat < AVIF_PIXEL_FORMAT_COUNT);
AVIF_CHECK(image->yuvRange == AVIF_RANGE_LIMITED || image->yuvRange == AVIF_RANGE_FULL);
// These matrix coefficients values are currently unsupported. Revise this list as more support is added.
//
// YCgCo performs limited-full range adjustment on R,G,B but the current implementation performs range adjustment
// on Y,U,V. So YCgCo with limited range is unsupported.
if ((image->matrixCoefficients == 3 /* CICP reserved */) ||
((image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
|| useYCgCo
#endif
) &&
(image->yuvRange == AVIF_RANGE_LIMITED)) ||
(image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_BT2020_CL) ||
(image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_SMPTE2085) ||
(image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_CL) ||
(image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_ICTCP) || (image->matrixCoefficients >= AVIF_MATRIX_COEFFICIENTS_LAST)) {
return AVIF_FALSE;
}
if ((image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_IDENTITY) && (image->yuvFormat != AVIF_PIXEL_FORMAT_YUV444) &&
(image->yuvFormat != AVIF_PIXEL_FORMAT_YUV400)) {
return AVIF_FALSE;
}
avifGetPixelFormatInfo(image->yuvFormat, &info->formatInfo);
avifCalcYUVCoefficients(image, &info->kr, &info->kg, &info->kb);
info->channelBytes = (image->depth > 8) ? 2 : 1;
info->depth = image->depth;
info->range = image->yuvRange;
info->maxChannel = (1 << image->depth) - 1;
info->biasY = (info->range == AVIF_RANGE_LIMITED) ? (float)(16 << (info->depth - 8)) : 0.0f;
info->biasUV = (float)(1 << (info->depth - 1));
info->rangeY = (float)((info->range == AVIF_RANGE_LIMITED) ? (219 << (info->depth - 8)) : info->maxChannel);
info->rangeUV = (float)((info->range == AVIF_RANGE_LIMITED) ? (224 << (info->depth - 8)) : info->maxChannel);
return AVIF_TRUE;
}
static avifBool avifPrepareReformatState(const avifImage * image, const avifRGBImage * rgb, avifReformatState * state)
{
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
const avifBool useYCgCoRe = (image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RE);
const avifBool useYCgCoRo = (image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RO);
if (useYCgCoRe || useYCgCoRo) {
const int bitOffset = (useYCgCoRe) ? 2 : 1;
if (image->depth - bitOffset != rgb->depth) {
return AVIF_FALSE;
}
}
#endif
AVIF_CHECK(avifGetRGBColorSpaceInfo(rgb, &state->rgb));
AVIF_CHECK(avifGetYUVColorSpaceInfo(image, &state->yuv));
state->yuv.mode = AVIF_REFORMAT_MODE_YUV_COEFFICIENTS;
if (image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_IDENTITY) {
state->yuv.mode = AVIF_REFORMAT_MODE_IDENTITY;
} else if (image->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO) {
state->yuv.mode = AVIF_REFORMAT_MODE_YCGCO;
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
} else if (useYCgCoRe) {
state->yuv.mode = AVIF_REFORMAT_MODE_YCGCO_RE;
} else if (useYCgCoRo) {
state->yuv.mode = AVIF_REFORMAT_MODE_YCGCO_RO;
#endif
}
if (state->yuv.mode != AVIF_REFORMAT_MODE_YUV_COEFFICIENTS) {
state->yuv.kr = 0.0f;
state->yuv.kg = 0.0f;
state->yuv.kb = 0.0f;
}
return AVIF_TRUE;
}
// Formulas 20-31 from https://www.itu.int/rec/T-REC-H.273-201612-I/en
static int avifYUVColorSpaceInfoYToUNorm(avifYUVColorSpaceInfo * info, float v)
{
int unorm = (int)avifRoundf(v * info->rangeY + info->biasY);
return AVIF_CLAMP(unorm, 0, info->maxChannel);
}
static int avifYUVColorSpaceInfoUVToUNorm(avifYUVColorSpaceInfo * info, float v)
{
int unorm;
// YCgCo performs limited-full range adjustment on R,G,B but the current implementation performs range adjustment
// on Y,U,V. So YCgCo with limited range is unsupported.
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
assert((info->mode != AVIF_REFORMAT_MODE_YCGCO && info->mode != AVIF_REFORMAT_MODE_YCGCO_RE && info->mode != AVIF_REFORMAT_MODE_YCGCO_RO) ||
(info->range == AVIF_RANGE_FULL));
#else
assert((info->mode != AVIF_REFORMAT_MODE_YCGCO) || (info->range == AVIF_RANGE_FULL));
#endif
if (info->mode == AVIF_REFORMAT_MODE_IDENTITY) {
unorm = (int)avifRoundf(v * info->rangeY + info->biasY);
} else {
unorm = (int)avifRoundf(v * info->rangeUV + info->biasUV);
}
return AVIF_CLAMP(unorm, 0, info->maxChannel);
}
avifResult avifImageRGBToYUV(avifImage * image, const avifRGBImage * rgb)
{
if (!rgb->pixels || rgb->format == AVIF_RGB_FORMAT_RGB_565) {
return AVIF_RESULT_REFORMAT_FAILED;
}
avifReformatState state;
if (!avifPrepareReformatState(image, rgb, &state)) {
return AVIF_RESULT_REFORMAT_FAILED;
}
if (rgb->isFloat) {
return AVIF_RESULT_NOT_IMPLEMENTED;
}
const avifBool hasAlpha = avifRGBFormatHasAlpha(rgb->format) && !rgb->ignoreAlpha;
avifResult allocationResult = avifImageAllocatePlanes(image, hasAlpha ? AVIF_PLANES_ALL : AVIF_PLANES_YUV);
if (allocationResult != AVIF_RESULT_OK) {
return allocationResult;
}
avifAlphaMultiplyMode alphaMode = AVIF_ALPHA_MULTIPLY_MODE_NO_OP;
if (hasAlpha) {
if (!rgb->alphaPremultiplied && image->alphaPremultiplied) {
alphaMode = AVIF_ALPHA_MULTIPLY_MODE_MULTIPLY;
} else if (rgb->alphaPremultiplied && !image->alphaPremultiplied) {
alphaMode = AVIF_ALPHA_MULTIPLY_MODE_UNMULTIPLY;
}
}
avifBool converted = AVIF_FALSE;
// Try converting with libsharpyuv.
if ((rgb->chromaDownsampling == AVIF_CHROMA_DOWNSAMPLING_SHARP_YUV) && (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV420)) {
const avifResult libSharpYUVResult = avifImageRGBToYUVLibSharpYUV(image, rgb, &state);
if (libSharpYUVResult != AVIF_RESULT_OK) {
// Return the error if sharpyuv was requested but failed for any reason, including libsharpyuv not being available.
return libSharpYUVResult;
}
converted = AVIF_TRUE;
}
if (!converted && !rgb->avoidLibYUV && (alphaMode == AVIF_ALPHA_MULTIPLY_MODE_NO_OP)) {
avifResult libyuvResult = avifImageRGBToYUVLibYUV(image, rgb);
if (libyuvResult == AVIF_RESULT_OK) {
converted = AVIF_TRUE;
} else if (libyuvResult != AVIF_RESULT_NOT_IMPLEMENTED) {
return libyuvResult;
}
}
if (!converted) {
const float kr = state.yuv.kr;
const float kg = state.yuv.kg;
const float kb = state.yuv.kb;
struct YUVBlock yuvBlock[2][2];
float rgbPixel[3];
const float rgbMaxChannelF = state.rgb.maxChannelF;
uint8_t ** yuvPlanes = image->yuvPlanes;
uint32_t * yuvRowBytes = image->yuvRowBytes;
for (uint32_t outerJ = 0; outerJ < image->height; outerJ += 2) {
for (uint32_t outerI = 0; outerI < image->width; outerI += 2) {
int blockW = 2, blockH = 2;
if ((outerI + 1) >= image->width) {
blockW = 1;
}
if ((outerJ + 1) >= image->height) {
blockH = 1;
}
// Convert an entire 2x2 block to YUV, and populate any fully sampled channels as we go
for (int bJ = 0; bJ < blockH; ++bJ) {
for (int bI = 0; bI < blockW; ++bI) {
int i = outerI + bI;
int j = outerJ + bJ;
// Unpack RGB into normalized float
if (state.rgb.channelBytes > 1) {
rgbPixel[0] =
*((uint16_t *)(&rgb->pixels[state.rgb.offsetBytesR + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)])) /
rgbMaxChannelF;
rgbPixel[1] =
*((uint16_t *)(&rgb->pixels[state.rgb.offsetBytesG + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)])) /
rgbMaxChannelF;
rgbPixel[2] =
*((uint16_t *)(&rgb->pixels[state.rgb.offsetBytesB + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)])) /
rgbMaxChannelF;
} else {
rgbPixel[0] = rgb->pixels[state.rgb.offsetBytesR + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)] /
rgbMaxChannelF;
rgbPixel[1] = rgb->pixels[state.rgb.offsetBytesG + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)] /
rgbMaxChannelF;
rgbPixel[2] = rgb->pixels[state.rgb.offsetBytesB + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)] /
rgbMaxChannelF;
}
if (alphaMode != AVIF_ALPHA_MULTIPLY_MODE_NO_OP) {
float a;
if (state.rgb.channelBytes > 1) {
a = *((uint16_t *)(&rgb->pixels[state.rgb.offsetBytesA + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)])) /
rgbMaxChannelF;
} else {
a = rgb->pixels[state.rgb.offsetBytesA + (i * state.rgb.pixelBytes) + (j * rgb->rowBytes)] / rgbMaxChannelF;
}
if (alphaMode == AVIF_ALPHA_MULTIPLY_MODE_MULTIPLY) {
if (a == 0) {
rgbPixel[0] = 0;
rgbPixel[1] = 0;
rgbPixel[2] = 0;
} else if (a < 1.0f) {
rgbPixel[0] *= a;
rgbPixel[1] *= a;
rgbPixel[2] *= a;
}
} else {
// alphaMode == AVIF_ALPHA_MULTIPLY_MODE_UNMULTIPLY
if (a == 0) {
rgbPixel[0] = 0;
rgbPixel[1] = 0;
rgbPixel[2] = 0;
} else if (a < 1.0f) {
rgbPixel[0] /= a;
rgbPixel[1] /= a;
rgbPixel[2] /= a;
rgbPixel[0] = AVIF_MIN(rgbPixel[0], 1.0f);
rgbPixel[1] = AVIF_MIN(rgbPixel[1], 1.0f);
rgbPixel[2] = AVIF_MIN(rgbPixel[2], 1.0f);
}
}
}
// RGB -> YUV conversion
if (state.yuv.mode == AVIF_REFORMAT_MODE_IDENTITY) {
// Formulas 41,42,43 from https://www.itu.int/rec/T-REC-H.273-201612-I/en
yuvBlock[bI][bJ].y = rgbPixel[1]; // G
yuvBlock[bI][bJ].u = rgbPixel[2]; // B
yuvBlock[bI][bJ].v = rgbPixel[0]; // R
} else if (state.yuv.mode == AVIF_REFORMAT_MODE_YCGCO) {
// Formulas 44,45,46 from https://www.itu.int/rec/T-REC-H.273-201612-I/en
yuvBlock[bI][bJ].y = 0.5f * rgbPixel[1] + 0.25f * (rgbPixel[0] + rgbPixel[2]);
yuvBlock[bI][bJ].u = 0.5f * rgbPixel[1] - 0.25f * (rgbPixel[0] + rgbPixel[2]);
yuvBlock[bI][bJ].v = 0.5f * (rgbPixel[0] - rgbPixel[2]);
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
} else if (state.yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RE || state.yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RO) {
// Formulas from JVET-U0093.
const int R = (int)avifRoundf(AVIF_CLAMP(rgbPixel[0] * rgbMaxChannelF, 0.0f, rgbMaxChannelF));
const int G = (int)avifRoundf(AVIF_CLAMP(rgbPixel[1] * rgbMaxChannelF, 0.0f, rgbMaxChannelF));
const int B = (int)avifRoundf(AVIF_CLAMP(rgbPixel[2] * rgbMaxChannelF, 0.0f, rgbMaxChannelF));
const int Co = R - B;
const int t = B + (Co >> 1);
const int Cg = G - t;
yuvBlock[bI][bJ].y = (t + (Cg >> 1)) / state.yuv.rangeY;
yuvBlock[bI][bJ].u = Cg / state.yuv.rangeUV;
yuvBlock[bI][bJ].v = Co / state.yuv.rangeUV;
#endif
} else {
float Y = (kr * rgbPixel[0]) + (kg * rgbPixel[1]) + (kb * rgbPixel[2]);
yuvBlock[bI][bJ].y = Y;
yuvBlock[bI][bJ].u = (rgbPixel[2] - Y) / (2 * (1 - kb));
yuvBlock[bI][bJ].v = (rgbPixel[0] - Y) / (2 * (1 - kr));
}
if (state.yuv.channelBytes > 1) {
uint16_t * pY = (uint16_t *)&yuvPlanes[AVIF_CHAN_Y][(i * 2) + (j * yuvRowBytes[AVIF_CHAN_Y])];
*pY = (uint16_t)avifYUVColorSpaceInfoYToUNorm(&state.yuv, yuvBlock[bI][bJ].y);
if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV444) {
// YUV444, full chroma
uint16_t * pU = (uint16_t *)&yuvPlanes[AVIF_CHAN_U][(i * 2) + (j * yuvRowBytes[AVIF_CHAN_U])];
*pU = (uint16_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, yuvBlock[bI][bJ].u);
uint16_t * pV = (uint16_t *)&yuvPlanes[AVIF_CHAN_V][(i * 2) + (j * yuvRowBytes[AVIF_CHAN_V])];
*pV = (uint16_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, yuvBlock[bI][bJ].v);
}
} else {
yuvPlanes[AVIF_CHAN_Y][i + (j * yuvRowBytes[AVIF_CHAN_Y])] =
(uint8_t)avifYUVColorSpaceInfoYToUNorm(&state.yuv, yuvBlock[bI][bJ].y);
if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV444) {
// YUV444, full chroma
yuvPlanes[AVIF_CHAN_U][i + (j * yuvRowBytes[AVIF_CHAN_U])] =
(uint8_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, yuvBlock[bI][bJ].u);
yuvPlanes[AVIF_CHAN_V][i + (j * yuvRowBytes[AVIF_CHAN_V])] =
(uint8_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, yuvBlock[bI][bJ].v);
}
}
}
}
// Populate any subsampled channels with averages from the 2x2 block
if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV400) {
// Do nothing on chroma planes.
} else if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV420) {
// YUV420, average 4 samples (2x2)
float sumU = 0.0f;
float sumV = 0.0f;
for (int bJ = 0; bJ < blockH; ++bJ) {
for (int bI = 0; bI < blockW; ++bI) {
sumU += yuvBlock[bI][bJ].u;
sumV += yuvBlock[bI][bJ].v;
}
}
float totalSamples = (float)(blockW * blockH);
float avgU = sumU / totalSamples;
float avgV = sumV / totalSamples;
const int chromaShiftX = 1;
const int chromaShiftY = 1;
int uvI = outerI >> chromaShiftX;
int uvJ = outerJ >> chromaShiftY;
if (state.yuv.channelBytes > 1) {
uint16_t * pU = (uint16_t *)&yuvPlanes[AVIF_CHAN_U][(uvI * 2) + (uvJ * yuvRowBytes[AVIF_CHAN_U])];
*pU = (uint16_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgU);
uint16_t * pV = (uint16_t *)&yuvPlanes[AVIF_CHAN_V][(uvI * 2) + (uvJ * yuvRowBytes[AVIF_CHAN_V])];
*pV = (uint16_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgV);
} else {
yuvPlanes[AVIF_CHAN_U][uvI + (uvJ * yuvRowBytes[AVIF_CHAN_U])] =
(uint8_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgU);
yuvPlanes[AVIF_CHAN_V][uvI + (uvJ * yuvRowBytes[AVIF_CHAN_V])] =
(uint8_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgV);
}
} else if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV422) {
// YUV422, average 2 samples (1x2), twice
for (int bJ = 0; bJ < blockH; ++bJ) {
float sumU = 0.0f;
float sumV = 0.0f;
for (int bI = 0; bI < blockW; ++bI) {
sumU += yuvBlock[bI][bJ].u;
sumV += yuvBlock[bI][bJ].v;
}
float totalSamples = (float)blockW;
float avgU = sumU / totalSamples;
float avgV = sumV / totalSamples;
const int chromaShiftX = 1;
int uvI = outerI >> chromaShiftX;
int uvJ = outerJ + bJ;
if (state.yuv.channelBytes > 1) {
uint16_t * pU = (uint16_t *)&yuvPlanes[AVIF_CHAN_U][(uvI * 2) + (uvJ * yuvRowBytes[AVIF_CHAN_U])];
*pU = (uint16_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgU);
uint16_t * pV = (uint16_t *)&yuvPlanes[AVIF_CHAN_V][(uvI * 2) + (uvJ * yuvRowBytes[AVIF_CHAN_V])];
*pV = (uint16_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgV);
} else {
yuvPlanes[AVIF_CHAN_U][uvI + (uvJ * yuvRowBytes[AVIF_CHAN_U])] =
(uint8_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgU);
yuvPlanes[AVIF_CHAN_V][uvI + (uvJ * yuvRowBytes[AVIF_CHAN_V])] =
(uint8_t)avifYUVColorSpaceInfoUVToUNorm(&state.yuv, avgV);
}
}
}
}
}
}
if (image->alphaPlane && image->alphaRowBytes) {
avifAlphaParams params;
params.width = image->width;
params.height = image->height;
params.dstDepth = image->depth;
params.dstPlane = image->alphaPlane;
params.dstRowBytes = image->alphaRowBytes;
params.dstOffsetBytes = 0;
params.dstPixelBytes = state.yuv.channelBytes;
if (avifRGBFormatHasAlpha(rgb->format) && !rgb->ignoreAlpha) {
params.srcDepth = rgb->depth;
params.srcPlane = rgb->pixels;
params.srcRowBytes = rgb->rowBytes;
params.srcOffsetBytes = state.rgb.offsetBytesA;
params.srcPixelBytes = state.rgb.pixelBytes;
avifReformatAlpha(&params);
} else {
// libyuv does not fill alpha when converting from RGB to YUV so
// fill it regardless of the value of convertedWithLibYUV.
avifFillAlpha(&params);
}
}
return AVIF_RESULT_OK;
}
// Allocates and fills look-up tables for going from YUV limited/full unorm -> full range RGB FP32.
// Review this when implementing YCgCo limited range support.
static avifBool avifCreateYUVToRGBLookUpTables(float ** unormFloatTableY, float ** unormFloatTableUV, uint32_t depth, const avifReformatState * state)
{
const size_t cpCount = (size_t)1 << depth;
assert(unormFloatTableY);
*unormFloatTableY = (float *)avifAlloc(cpCount * sizeof(float));
AVIF_CHECK(*unormFloatTableY);
for (uint32_t cp = 0; cp < cpCount; ++cp) {
(*unormFloatTableY)[cp] = ((float)cp - state->yuv.biasY) / state->yuv.rangeY;
}
if (unormFloatTableUV) {
if (state->yuv.mode == AVIF_REFORMAT_MODE_IDENTITY) {
// Just reuse the luma table since the chroma values are the same.
*unormFloatTableUV = *unormFloatTableY;
} else {
*unormFloatTableUV = (float *)avifAlloc(cpCount * sizeof(float));
if (!*unormFloatTableUV) {
avifFree(*unormFloatTableY);
*unormFloatTableY = NULL;
return AVIF_FALSE;
}
for (uint32_t cp = 0; cp < cpCount; ++cp) {
(*unormFloatTableUV)[cp] = ((float)cp - state->yuv.biasUV) / state->yuv.rangeUV;
}
}
}
return AVIF_TRUE;
}
// Frees look-up tables allocated with avifCreateYUVToRGBLookUpTables().
static void avifFreeYUVToRGBLookUpTables(float ** unormFloatTableY, float ** unormFloatTableUV)
{
if (unormFloatTableUV) {
if (*unormFloatTableUV != *unormFloatTableY) {
avifFree(*unormFloatTableUV);
}
*unormFloatTableUV = NULL;
}
avifFree(*unormFloatTableY);
*unormFloatTableY = NULL;
}
#define RGB565(R, G, B) ((uint16_t)(((B) >> 3) | (((G) >> 2) << 5) | (((R) >> 3) << 11)))
static void avifStoreRGB8Pixel(avifRGBFormat format, uint8_t R, uint8_t G, uint8_t B, uint8_t * ptrR, uint8_t * ptrG, uint8_t * ptrB)
{
if (format == AVIF_RGB_FORMAT_RGB_565) {
// References for RGB565 color conversion:
// * https://docs.microsoft.com/en-us/windows/win32/directshow/working-with-16-bit-rgb
// * https://chromium.googlesource.com/libyuv/libyuv/+/9892d70c965678381d2a70a1c9002d1cf136ee78/source/row_common.cc#2362
*(uint16_t *)ptrR = RGB565(R, G, B);
return;
}
*ptrR = R;
*ptrG = G;
*ptrB = B;
}
static void avifGetRGB565(const uint8_t * ptrR, uint8_t * R, uint8_t * G, uint8_t * B)
{
// References for RGB565 color conversion:
// * https://docs.microsoft.com/en-us/windows/win32/directshow/working-with-16-bit-rgb
// * https://chromium.googlesource.com/libyuv/libyuv/+/331c361581896292fb46c8c6905e41262b7ca95f/source/row_common.cc#185
const uint16_t rgb656 = ((const uint16_t *)ptrR)[0];
const uint16_t r5 = (rgb656 & 0xF800) >> 11;
const uint16_t g6 = (rgb656 & 0x07E0) >> 5;
const uint16_t b5 = (rgb656 & 0x001F);
*R = (uint8_t)((r5 << 3) | (r5 >> 2));
*G = (uint8_t)((g6 << 2) | (g6 >> 4));
*B = (uint8_t)((b5 << 3) | (b5 >> 2));
}
// Note: This function handles alpha (un)multiply.
static avifResult avifImageYUVAnyToRGBAnySlow(const avifImage * image,
avifRGBImage * rgb,
const avifReformatState * state,
avifAlphaMultiplyMode alphaMultiplyMode)
{
// Aliases for some state
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
float * unormFloatTableY = NULL;
float * unormFloatTableUV = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const uint32_t yuvChannelBytes = state->yuv.channelBytes;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
// Aliases for plane data
const uint8_t * yPlane = image->yuvPlanes[AVIF_CHAN_Y];
const uint8_t * uPlane = image->yuvPlanes[AVIF_CHAN_U];
const uint8_t * vPlane = image->yuvPlanes[AVIF_CHAN_V];
const uint8_t * aPlane = image->alphaPlane;
const uint32_t yRowBytes = image->yuvRowBytes[AVIF_CHAN_Y];
const uint32_t uRowBytes = image->yuvRowBytes[AVIF_CHAN_U];
const uint32_t vRowBytes = image->yuvRowBytes[AVIF_CHAN_V];
const uint32_t aRowBytes = image->alphaRowBytes;
// Various observations and limits
const avifBool hasColor = (uPlane && vPlane && (image->yuvFormat != AVIF_PIXEL_FORMAT_YUV400));
const uint16_t yuvMaxChannel = (uint16_t)state->yuv.maxChannel;
const float rgbMaxChannelF = state->rgb.maxChannelF;
// If toRGBAlphaMode is active (not no-op), assert that the alpha plane is present. The end of
// the avifPrepareReformatState() function should ensure this, but this assert makes it clear
// to clang's analyzer.
assert((alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_NO_OP) || aPlane);
for (uint32_t j = 0; j < image->height; ++j) {
// uvJ is used only when hasColor is true.
const uint32_t uvJ = hasColor ? (j >> state->yuv.formatInfo.chromaShiftY) : 0;
const uint8_t * ptrY8 = &yPlane[j * yRowBytes];
const uint8_t * ptrU8 = uPlane ? &uPlane[(uvJ * uRowBytes)] : NULL;
const uint8_t * ptrV8 = vPlane ? &vPlane[(uvJ * vRowBytes)] : NULL;
const uint8_t * ptrA8 = aPlane ? &aPlane[j * aRowBytes] : NULL;
const uint16_t * ptrY16 = (const uint16_t *)ptrY8;
const uint16_t * ptrU16 = (const uint16_t *)ptrU8;
const uint16_t * ptrV16 = (const uint16_t *)ptrV8;
const uint16_t * ptrA16 = (const uint16_t *)ptrA8;
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
float Y, Cb = 0.5f, Cr = 0.5f;
// Calculate Y
uint16_t unormY;
if (image->depth == 8) {
unormY = ptrY8[i];
} else {
// clamp incoming data to protect against bad LUT lookups
unormY = AVIF_MIN(ptrY16[i], yuvMaxChannel);
}
Y = unormFloatTableY[unormY];
// Calculate Cb and Cr
if (hasColor) {
const uint32_t uvI = i >> state->yuv.formatInfo.chromaShiftX;
if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV444) {
uint16_t unormU, unormV;
if (image->depth == 8) {
unormU = ptrU8[uvI];
unormV = ptrV8[uvI];
} else {
// clamp incoming data to protect against bad LUT lookups
unormU = AVIF_MIN(ptrU16[uvI], yuvMaxChannel);
unormV = AVIF_MIN(ptrV16[uvI], yuvMaxChannel);
}
Cb = unormFloatTableUV[unormU];
Cr = unormFloatTableUV[unormV];
} else {
// Upsample to 444:
//
// * * * *
// A B
// * 1 2 *
//
// * 3 4 *
// C D
// * * * *
//
// When converting from YUV420 to RGB, for any given "high-resolution" RGB
// coordinate (1,2,3,4,*), there are up to four "low-resolution" UV samples
// (A,B,C,D) that are "nearest" to the pixel. For RGB pixel #1, A is the closest
// UV sample, B and C are "adjacent" to it on the same row and column, and D is
// the diagonal. For RGB pixel 3, C is the closest UV sample, A and D are
// adjacent, and B is the diagonal. Sometimes the adjacent pixel on the same row
// is to the left or right, and sometimes the adjacent pixel on the same column
// is up or down. For any edge or corner, there might only be only one or two
// samples nearby, so they'll be duplicated.
//
// The following code attempts to find all four nearest UV samples and put them
// in the following unormU and unormV grid as follows:
//
// unorm[0][0] = closest ( weights: bilinear: 9/16, nearest: 1 )
// unorm[1][0] = adjacent col ( weights: bilinear: 3/16, nearest: 0 )
// unorm[0][1] = adjacent row ( weights: bilinear: 3/16, nearest: 0 )
// unorm[1][1] = diagonal ( weights: bilinear: 1/16, nearest: 0 )
//
// It then weights them according to the requested upsampling set in avifRGBImage.
uint16_t unormU[2][2], unormV[2][2];
// How many bytes to add to a uint8_t pointer index to get to the adjacent (lesser) sample in a given direction
int uAdjCol, vAdjCol, uAdjRow, vAdjRow;
if ((i == 0) || ((i == (image->width - 1)) && ((i % 2) != 0))) {
uAdjCol = 0;
vAdjCol = 0;
} else {
if ((i % 2) != 0) {
uAdjCol = yuvChannelBytes;
vAdjCol = yuvChannelBytes;
} else {
uAdjCol = -1 * yuvChannelBytes;
vAdjCol = -1 * yuvChannelBytes;
}
}
// For YUV422, uvJ will always be a fresh value (always corresponds to j), so
// we'll simply duplicate the sample as if we were on the top or bottom row and
// it'll behave as plain old linear (1D) upsampling, which is all we want.
if ((j == 0) || ((j == (image->height - 1)) && ((j % 2) != 0)) || (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV422)) {
uAdjRow = 0;
vAdjRow = 0;
} else {
if ((j % 2) != 0) {
uAdjRow = (int)uRowBytes;
vAdjRow = (int)vRowBytes;
} else {
uAdjRow = -1 * (int)uRowBytes;
vAdjRow = -1 * (int)vRowBytes;
}
}
if (image->depth == 8) {
unormU[0][0] = uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes)];
unormV[0][0] = vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes)];
unormU[1][0] = uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes) + uAdjCol];
unormV[1][0] = vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes) + vAdjCol];
unormU[0][1] = uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes) + uAdjRow];
unormV[0][1] = vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes) + vAdjRow];
unormU[1][1] = uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes) + uAdjCol + uAdjRow];
unormV[1][1] = vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes) + vAdjCol + vAdjRow];
} else {
unormU[0][0] = *((const uint16_t *)&uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes)]);
unormV[0][0] = *((const uint16_t *)&vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes)]);
unormU[1][0] = *((const uint16_t *)&uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes) + uAdjCol]);
unormV[1][0] = *((const uint16_t *)&vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes) + vAdjCol]);
unormU[0][1] = *((const uint16_t *)&uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes) + uAdjRow]);
unormV[0][1] = *((const uint16_t *)&vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes) + vAdjRow]);
unormU[1][1] = *((const uint16_t *)&uPlane[(uvJ * uRowBytes) + (uvI * yuvChannelBytes) + uAdjCol + uAdjRow]);
unormV[1][1] = *((const uint16_t *)&vPlane[(uvJ * vRowBytes) + (uvI * yuvChannelBytes) + vAdjCol + vAdjRow]);
// clamp incoming data to protect against bad LUT lookups
for (int bJ = 0; bJ < 2; ++bJ) {
for (int bI = 0; bI < 2; ++bI) {
unormU[bI][bJ] = AVIF_MIN(unormU[bI][bJ], yuvMaxChannel);
unormV[bI][bJ] = AVIF_MIN(unormV[bI][bJ], yuvMaxChannel);
}
}
}
if ((rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_FASTEST) ||
(rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_NEAREST)) {
// Nearest neighbor; ignore all UVs but the closest one
Cb = unormFloatTableUV[unormU[0][0]];
Cr = unormFloatTableUV[unormV[0][0]];
} else {
// Bilinear filtering with weights
Cb = (unormFloatTableUV[unormU[0][0]] * (9.0f / 16.0f)) + (unormFloatTableUV[unormU[1][0]] * (3.0f / 16.0f)) +
(unormFloatTableUV[unormU[0][1]] * (3.0f / 16.0f)) + (unormFloatTableUV[unormU[1][1]] * (1.0f / 16.0f));
Cr = (unormFloatTableUV[unormV[0][0]] * (9.0f / 16.0f)) + (unormFloatTableUV[unormV[1][0]] * (3.0f / 16.0f)) +
(unormFloatTableUV[unormV[0][1]] * (3.0f / 16.0f)) + (unormFloatTableUV[unormV[1][1]] * (1.0f / 16.0f));
}
}
}
float R, G, B;
if (hasColor) {
if (state->yuv.mode == AVIF_REFORMAT_MODE_IDENTITY) {
// Identity (GBR): Formulas 41,42,43 from https://www.itu.int/rec/T-REC-H.273-201612-I/en
G = Y;
B = Cb;
R = Cr;
} else if (state->yuv.mode == AVIF_REFORMAT_MODE_YCGCO) {
// YCgCo: Formulas 47,48,49,50 from https://www.itu.int/rec/T-REC-H.273-201612-I/en
const float t = Y - Cb;
G = Y + Cb;
B = t - Cr;
R = t + Cr;
#if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R)
} else if (state->yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RE || state->yuv.mode == AVIF_REFORMAT_MODE_YCGCO_RO) {
const int YY = unormY;
const int Cg = (int)avifRoundf(Cb * yuvMaxChannel);
const int Co = (int)avifRoundf(Cr * yuvMaxChannel);
const int t = YY - (Cg >> 1);
G = (float)AVIF_CLAMP(t + Cg, 0, state->rgb.maxChannel);
B = (float)AVIF_CLAMP(t - (Co >> 1), 0, state->rgb.maxChannel);
R = (float)AVIF_CLAMP(B + Co, 0, state->rgb.maxChannel);
G /= rgbMaxChannelF;
B /= rgbMaxChannelF;
R /= rgbMaxChannelF;
#endif
} else {
// Normal YUV
R = Y + (2 * (1 - kr)) * Cr;
B = Y + (2 * (1 - kb)) * Cb;
G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
}
} else {
// Monochrome: just populate all channels with luma (state->yuv.mode is irrelevant)
R = Y;
G = Y;
B = Y;
}
float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
if (alphaMultiplyMode != AVIF_ALPHA_MULTIPLY_MODE_NO_OP) {
// Calculate A
uint16_t unormA;
if (image->depth == 8) {
unormA = ptrA8[i];
} else {
unormA = AVIF_MIN(ptrA16[i], yuvMaxChannel);
}
const float A = unormA / ((float)state->yuv.maxChannel);
const float Ac = AVIF_CLAMP(A, 0.0f, 1.0f);
if (alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_MULTIPLY) {
if (Ac == 0.0f) {
Rc = 0.0f;
Gc = 0.0f;
Bc = 0.0f;
} else if (Ac < 1.0f) {
Rc *= Ac;
Gc *= Ac;
Bc *= Ac;
}
} else {
// alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_UNMULTIPLY
if (Ac == 0.0f) {
Rc = 0.0f;
Gc = 0.0f;
Bc = 0.0f;
} else if (Ac < 1.0f) {
Rc /= Ac;
Gc /= Ac;
Bc /= Ac;
Rc = AVIF_MIN(Rc, 1.0f);
Gc = AVIF_MIN(Gc, 1.0f);
Bc = AVIF_MIN(Bc, 1.0f);
}
}
}
if (rgb->depth == 8) {
avifStoreRGB8Pixel(rgb->format,
(uint8_t)(0.5f + (Rc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Gc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Bc * rgbMaxChannelF)),
ptrR,
ptrG,
ptrB);
} else {
*((uint16_t *)ptrR) = (uint16_t)(0.5f + (Rc * rgbMaxChannelF));
*((uint16_t *)ptrG) = (uint16_t)(0.5f + (Gc * rgbMaxChannelF));
*((uint16_t *)ptrB) = (uint16_t)(0.5f + (Bc * rgbMaxChannelF));
}
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV16ToRGB16Color(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
float * unormFloatTableUV = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const uint16_t yuvMaxChannel = (uint16_t)state->yuv.maxChannel;
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint32_t uvJ = j >> state->yuv.formatInfo.chromaShiftY;
const uint16_t * const ptrY = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
const uint16_t * const ptrU = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_U][(uvJ * image->yuvRowBytes[AVIF_CHAN_U])];
const uint16_t * const ptrV = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_V][(uvJ * image->yuvRowBytes[AVIF_CHAN_V])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
uint32_t uvI = i >> state->yuv.formatInfo.chromaShiftX;
// clamp incoming data to protect against bad LUT lookups
const uint16_t unormY = AVIF_MIN(ptrY[i], yuvMaxChannel);
const uint16_t unormU = AVIF_MIN(ptrU[uvI], yuvMaxChannel);
const uint16_t unormV = AVIF_MIN(ptrV[uvI], yuvMaxChannel);
// Convert unorm to float
const float Y = unormFloatTableY[unormY];
const float Cb = unormFloatTableUV[unormU];
const float Cr = unormFloatTableUV[unormV];
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
*((uint16_t *)ptrR) = (uint16_t)(0.5f + (Rc * rgbMaxChannelF));
*((uint16_t *)ptrG) = (uint16_t)(0.5f + (Gc * rgbMaxChannelF));
*((uint16_t *)ptrB) = (uint16_t)(0.5f + (Bc * rgbMaxChannelF));
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV16ToRGB16Mono(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, NULL, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const uint16_t maxChannel = (uint16_t)state->yuv.maxChannel;
const float maxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint16_t * const ptrY = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
// clamp incoming data to protect against bad LUT lookups
const uint16_t unormY = AVIF_MIN(ptrY[i], maxChannel);
// Convert unorm to float
const float Y = unormFloatTableY[unormY];
const float Cb = 0.0f;
const float Cr = 0.0f;
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
*((uint16_t *)ptrR) = (uint16_t)(0.5f + (Rc * maxChannelF));
*((uint16_t *)ptrG) = (uint16_t)(0.5f + (Gc * maxChannelF));
*((uint16_t *)ptrB) = (uint16_t)(0.5f + (Bc * maxChannelF));
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, NULL);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV16ToRGB8Color(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
float * unormFloatTableUV = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const uint16_t yuvMaxChannel = (uint16_t)state->yuv.maxChannel;
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint32_t uvJ = j >> state->yuv.formatInfo.chromaShiftY;
const uint16_t * const ptrY = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
const uint16_t * const ptrU = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_U][(uvJ * image->yuvRowBytes[AVIF_CHAN_U])];
const uint16_t * const ptrV = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_V][(uvJ * image->yuvRowBytes[AVIF_CHAN_V])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
uint32_t uvI = i >> state->yuv.formatInfo.chromaShiftX;
// clamp incoming data to protect against bad LUT lookups
const uint16_t unormY = AVIF_MIN(ptrY[i], yuvMaxChannel);
const uint16_t unormU = AVIF_MIN(ptrU[uvI], yuvMaxChannel);
const uint16_t unormV = AVIF_MIN(ptrV[uvI], yuvMaxChannel);
// Convert unorm to float
const float Y = unormFloatTableY[unormY];
const float Cb = unormFloatTableUV[unormU];
const float Cr = unormFloatTableUV[unormV];
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
avifStoreRGB8Pixel(rgb->format,
(uint8_t)(0.5f + (Rc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Gc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Bc * rgbMaxChannelF)),
ptrR,
ptrG,
ptrB);
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV16ToRGB8Mono(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, NULL, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const uint16_t yuvMaxChannel = (uint16_t)state->yuv.maxChannel;
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint16_t * const ptrY = (uint16_t *)&image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
// clamp incoming data to protect against bad LUT lookups
const uint16_t unormY = AVIF_MIN(ptrY[i], yuvMaxChannel);
// Convert unorm to float
const float Y = unormFloatTableY[unormY];
const float Cb = 0.0f;
const float Cr = 0.0f;
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
avifStoreRGB8Pixel(rgb->format,
(uint8_t)(0.5f + (Rc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Gc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Bc * rgbMaxChannelF)),
ptrR,
ptrG,
ptrB);
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, NULL);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV8ToRGB16Color(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
float * unormFloatTableUV = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint32_t uvJ = j >> state->yuv.formatInfo.chromaShiftY;
const uint8_t * const ptrY = &image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
const uint8_t * const ptrU = &image->yuvPlanes[AVIF_CHAN_U][(uvJ * image->yuvRowBytes[AVIF_CHAN_U])];
const uint8_t * const ptrV = &image->yuvPlanes[AVIF_CHAN_V][(uvJ * image->yuvRowBytes[AVIF_CHAN_V])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
uint32_t uvI = i >> state->yuv.formatInfo.chromaShiftX;
// Convert unorm to float (no clamp necessary, the full uint8_t range is a legal lookup)
const float Y = unormFloatTableY[ptrY[i]];
const float Cb = unormFloatTableUV[ptrU[uvI]];
const float Cr = unormFloatTableUV[ptrV[uvI]];
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
*((uint16_t *)ptrR) = (uint16_t)(0.5f + (Rc * rgbMaxChannelF));
*((uint16_t *)ptrG) = (uint16_t)(0.5f + (Gc * rgbMaxChannelF));
*((uint16_t *)ptrB) = (uint16_t)(0.5f + (Bc * rgbMaxChannelF));
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV8ToRGB16Mono(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, NULL, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint8_t * const ptrY = &image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
// Convert unorm to float (no clamp necessary, the full uint8_t range is a legal lookup)
const float Y = unormFloatTableY[ptrY[i]];
const float Cb = 0.0f;
const float Cr = 0.0f;
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
*((uint16_t *)ptrR) = (uint16_t)(0.5f + (Rc * rgbMaxChannelF));
*((uint16_t *)ptrG) = (uint16_t)(0.5f + (Gc * rgbMaxChannelF));
*((uint16_t *)ptrB) = (uint16_t)(0.5f + (Bc * rgbMaxChannelF));
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, NULL);
return AVIF_RESULT_OK;
}
static avifResult avifImageIdentity8ToRGB8ColorFullRange(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
for (uint32_t j = 0; j < image->height; ++j) {
const uint8_t * const ptrY = &image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
const uint8_t * const ptrU = &image->yuvPlanes[AVIF_CHAN_U][(j * image->yuvRowBytes[AVIF_CHAN_U])];
const uint8_t * const ptrV = &image->yuvPlanes[AVIF_CHAN_V][(j * image->yuvRowBytes[AVIF_CHAN_V])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
// This is intentionally a per-row conditional instead of a per-pixel
// conditional. This makes the "else" path (much more common than the
// "if" path) much faster than having a per-pixel branch.
if (rgb->format == AVIF_RGB_FORMAT_RGB_565) {
for (uint32_t i = 0; i < image->width; ++i) {
*(uint16_t *)ptrR = RGB565(ptrV[i], ptrY[i], ptrU[i]);
ptrR += rgbPixelBytes;
}
} else {
for (uint32_t i = 0; i < image->width; ++i) {
*ptrR = ptrV[i];
*ptrG = ptrY[i];
*ptrB = ptrU[i];
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
}
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV8ToRGB8Color(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
float * unormFloatTableUV = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint32_t uvJ = j >> state->yuv.formatInfo.chromaShiftY;
const uint8_t * const ptrY = &image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
const uint8_t * const ptrU = &image->yuvPlanes[AVIF_CHAN_U][(uvJ * image->yuvRowBytes[AVIF_CHAN_U])];
const uint8_t * const ptrV = &image->yuvPlanes[AVIF_CHAN_V][(uvJ * image->yuvRowBytes[AVIF_CHAN_V])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
uint32_t uvI = i >> state->yuv.formatInfo.chromaShiftX;
// Convert unorm to float (no clamp necessary, the full uint8_t range is a legal lookup)
const float Y = unormFloatTableY[ptrY[i]];
const float Cb = unormFloatTableUV[ptrU[uvI]];
const float Cr = unormFloatTableUV[ptrV[uvI]];
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
avifStoreRGB8Pixel(rgb->format,
(uint8_t)(0.5f + (Rc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Gc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Bc * rgbMaxChannelF)),
ptrR,
ptrG,
ptrB);
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, &unormFloatTableUV);
return AVIF_RESULT_OK;
}
static avifResult avifImageYUV8ToRGB8Mono(const avifImage * image, avifRGBImage * rgb, avifReformatState * state)
{
const float kr = state->yuv.kr;
const float kg = state->yuv.kg;
const float kb = state->yuv.kb;
const uint32_t rgbPixelBytes = state->rgb.pixelBytes;
float * unormFloatTableY = NULL;
AVIF_CHECKERR(avifCreateYUVToRGBLookUpTables(&unormFloatTableY, NULL, image->depth, state), AVIF_RESULT_OUT_OF_MEMORY);
const float rgbMaxChannelF = state->rgb.maxChannelF;
for (uint32_t j = 0; j < image->height; ++j) {
const uint8_t * const ptrY = &image->yuvPlanes[AVIF_CHAN_Y][(j * image->yuvRowBytes[AVIF_CHAN_Y])];
uint8_t * ptrR = &rgb->pixels[state->rgb.offsetBytesR + (j * rgb->rowBytes)];
uint8_t * ptrG = &rgb->pixels[state->rgb.offsetBytesG + (j * rgb->rowBytes)];
uint8_t * ptrB = &rgb->pixels[state->rgb.offsetBytesB + (j * rgb->rowBytes)];
for (uint32_t i = 0; i < image->width; ++i) {
// Convert unorm to float (no clamp necessary, the full uint8_t range is a legal lookup)
const float Y = unormFloatTableY[ptrY[i]];
const float Cb = 0.0f;
const float Cr = 0.0f;
const float R = Y + (2 * (1 - kr)) * Cr;
const float B = Y + (2 * (1 - kb)) * Cb;
const float G = Y - ((2 * ((kr * (1 - kr) * Cr) + (kb * (1 - kb) * Cb))) / kg);
const float Rc = AVIF_CLAMP(R, 0.0f, 1.0f);
const float Gc = AVIF_CLAMP(G, 0.0f, 1.0f);
const float Bc = AVIF_CLAMP(B, 0.0f, 1.0f);
avifStoreRGB8Pixel(rgb->format,
(uint8_t)(0.5f + (Rc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Gc * rgbMaxChannelF)),
(uint8_t)(0.5f + (Bc * rgbMaxChannelF)),
ptrR,
ptrG,
ptrB);
ptrR += rgbPixelBytes;
ptrG += rgbPixelBytes;
ptrB += rgbPixelBytes;
}
}
avifFreeYUVToRGBLookUpTables(&unormFloatTableY, NULL);
return AVIF_RESULT_OK;
}
// This constant comes from libyuv. For details, see here:
// https://chromium.googlesource.com/libyuv/libyuv/+/2f87e9a7/source/row_common.cc#3537
#define F16_MULTIPLIER 1.9259299444e-34f
typedef union avifF16
{
float f;
uint32_t u32;
} avifF16;
static avifResult avifRGBImageToF16(avifRGBImage * rgb)
{
avifResult libyuvResult = AVIF_RESULT_NOT_IMPLEMENTED;
if (!rgb->avoidLibYUV) {
libyuvResult = avifRGBImageToF16LibYUV(rgb);
}
if (libyuvResult != AVIF_RESULT_NOT_IMPLEMENTED) {
return libyuvResult;
}
const uint32_t channelCount = avifRGBFormatChannelCount(rgb->format);
const float scale = 1.0f / ((1 << rgb->depth) - 1);
const float multiplier = F16_MULTIPLIER * scale;
uint16_t * pixelRowBase = (uint16_t *)rgb->pixels;
const uint32_t stride = rgb->rowBytes >> 1;
for (uint32_t j = 0; j < rgb->height; ++j) {
uint16_t * pixel = pixelRowBase;
for (uint32_t i = 0; i < rgb->width * channelCount; ++i, ++pixel) {
avifF16 f16;
f16.f = *pixel * multiplier;
*pixel = (uint16_t)(f16.u32 >> 13);
}
pixelRowBase += stride;
}
return AVIF_RESULT_OK;
}
static avifResult avifImageYUVToRGBImpl(const avifImage * image, avifRGBImage * rgb, avifReformatState * state, avifAlphaMultiplyMode alphaMultiplyMode)
{
avifBool convertedWithLibYUV = AVIF_FALSE;
// Reformat alpha, if user asks for it, or (un)multiply processing needs it.
avifBool reformatAlpha = avifRGBFormatHasAlpha(rgb->format) &&
(!rgb->ignoreAlpha || (alphaMultiplyMode != AVIF_ALPHA_MULTIPLY_MODE_NO_OP));
// This value is used only when reformatAlpha is true.
avifBool alphaReformattedWithLibYUV = AVIF_FALSE;
if (!rgb->avoidLibYUV && ((alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_NO_OP) || avifRGBFormatHasAlpha(rgb->format))) {
avifResult libyuvResult = avifImageYUVToRGBLibYUV(image, rgb, reformatAlpha, &alphaReformattedWithLibYUV);
if (libyuvResult == AVIF_RESULT_OK) {
convertedWithLibYUV = AVIF_TRUE;
} else {
if (libyuvResult != AVIF_RESULT_NOT_IMPLEMENTED) {
return libyuvResult;
}
}
}
if (reformatAlpha && !alphaReformattedWithLibYUV) {
avifAlphaParams params;
params.width = rgb->width;
params.height = rgb->height;
params.dstDepth = rgb->depth;
params.dstPlane = rgb->pixels;
params.dstRowBytes = rgb->rowBytes;
params.dstOffsetBytes = state->rgb.offsetBytesA;
params.dstPixelBytes = state->rgb.pixelBytes;
if (image->alphaPlane && image->alphaRowBytes) {
params.srcDepth = image->depth;
params.srcPlane = image->alphaPlane;
params.srcRowBytes = image->alphaRowBytes;
params.srcOffsetBytes = 0;
params.srcPixelBytes = state->yuv.channelBytes;
avifReformatAlpha(&params);
} else {
avifFillAlpha(&params);
}
}
if (!convertedWithLibYUV) {
// libyuv is either unavailable or unable to perform the specific conversion required here.
// Look over the available built-in "fast" routines for YUV->RGB conversion and see if one
// fits the current combination, or as a last resort, call avifImageYUVAnyToRGBAnySlow(),
// which handles every possibly YUV->RGB combination, but very slowly (in comparison).
avifResult convertResult = AVIF_RESULT_NOT_IMPLEMENTED;
const avifBool hasColor =
(image->yuvRowBytes[AVIF_CHAN_U] && image->yuvRowBytes[AVIF_CHAN_V] && (image->yuvFormat != AVIF_PIXEL_FORMAT_YUV400));
if ((!hasColor || (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV444) ||
((rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_FASTEST) || (rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_NEAREST))) &&
(alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_NO_OP || avifRGBFormatHasAlpha(rgb->format))) {
// Explanations on the above conditional:
// * None of these fast paths currently support bilinear upsampling, so avoid all of them
// unless the YUV data isn't subsampled or they explicitly requested AVIF_CHROMA_UPSAMPLING_NEAREST.
// * None of these fast paths currently handle alpha (un)multiply, so avoid all of them
// if we can't do alpha (un)multiply as a separated post step (destination format doesn't have alpha).
if (state->yuv.mode == AVIF_REFORMAT_MODE_IDENTITY) {
if ((image->depth == 8) && (rgb->depth == 8) && (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV444) &&
(image->yuvRange == AVIF_RANGE_FULL)) {
convertResult = avifImageIdentity8ToRGB8ColorFullRange(image, rgb, state);
}
// TODO: Add more fast paths for identity
} else if (state->yuv.mode == AVIF_REFORMAT_MODE_YUV_COEFFICIENTS) {
if (image->depth > 8) {
// yuv:u16
if (rgb->depth > 8) {
// yuv:u16, rgb:u16
if (hasColor) {
convertResult = avifImageYUV16ToRGB16Color(image, rgb, state);
} else {
convertResult = avifImageYUV16ToRGB16Mono(image, rgb, state);
}
} else {
// yuv:u16, rgb:u8
if (hasColor) {
convertResult = avifImageYUV16ToRGB8Color(image, rgb, state);
} else {
convertResult = avifImageYUV16ToRGB8Mono(image, rgb, state);
}
}
} else {
// yuv:u8
if (rgb->depth > 8) {
// yuv:u8, rgb:u16
if (hasColor) {
convertResult = avifImageYUV8ToRGB16Color(image, rgb, state);
} else {
convertResult = avifImageYUV8ToRGB16Mono(image, rgb, state);
}
} else {
// yuv:u8, rgb:u8
if (hasColor) {
convertResult = avifImageYUV8ToRGB8Color(image, rgb, state);
} else {
convertResult = avifImageYUV8ToRGB8Mono(image, rgb, state);
}
}
}
}
}
if (convertResult == AVIF_RESULT_NOT_IMPLEMENTED) {
// If we get here, there is no fast path for this combination. Time to be slow!
convertResult = avifImageYUVAnyToRGBAnySlow(image, rgb, state, alphaMultiplyMode);
// The slow path also handles alpha (un)multiply, so forget the operation here.
alphaMultiplyMode = AVIF_ALPHA_MULTIPLY_MODE_NO_OP;
}
if (convertResult != AVIF_RESULT_OK) {
return convertResult;
}
}
// Process alpha premultiplication, if necessary
if (alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_MULTIPLY) {
avifResult result = avifRGBImagePremultiplyAlpha(rgb);
if (result != AVIF_RESULT_OK) {
return result;
}
} else if (alphaMultiplyMode == AVIF_ALPHA_MULTIPLY_MODE_UNMULTIPLY) {
avifResult result = avifRGBImageUnpremultiplyAlpha(rgb);
if (result != AVIF_RESULT_OK) {
return result;
}
}
// Convert pixels to half floats (F16), if necessary.
if (rgb->isFloat) {
return avifRGBImageToF16(rgb);
}
return AVIF_RESULT_OK;
}
typedef struct
{
#if defined(_WIN32)
HANDLE thread;
#else
pthread_t thread;
#endif
avifImage image;
avifRGBImage rgb;
avifReformatState * state;
avifAlphaMultiplyMode alphaMultiplyMode;
avifResult result;
avifBool threadCreated;
} YUVToRGBThreadData;
#if defined(_WIN32)
static unsigned int __stdcall avifImageYUVToRGBThreadWorker(void * arg)
#else
static void * avifImageYUVToRGBThreadWorker(void * arg)
#endif
{
YUVToRGBThreadData * data = (YUVToRGBThreadData *)arg;
data->result = avifImageYUVToRGBImpl(&data->image, &data->rgb, data->state, data->alphaMultiplyMode);
#if defined(_WIN32)
return 0;
#else
return NULL;
#endif
}
static avifBool avifCreateYUVToRGBThread(YUVToRGBThreadData * tdata)
{
#if defined(_WIN32)
tdata->thread = (HANDLE)_beginthreadex(/*security=*/NULL,
/*stack_size=*/0,
&avifImageYUVToRGBThreadWorker,
tdata,
/*initflag=*/0,
/*thrdaddr=*/NULL);
return tdata->thread != NULL;
#else
// TODO: Set the thread name for ease of debugging.
return pthread_create(&tdata->thread, NULL, &avifImageYUVToRGBThreadWorker, tdata) == 0;
#endif
}
static avifBool avifJoinYUVToRGBThread(YUVToRGBThreadData * tdata)
{
#if defined(_WIN32)
return WaitForSingleObject(tdata->thread, INFINITE) == WAIT_OBJECT_0 && CloseHandle(tdata->thread) != 0;
#else
return pthread_join(tdata->thread, NULL) == 0;
#endif
}
avifResult avifImageYUVToRGB(const avifImage * image, avifRGBImage * rgb)
{
// It is okay for rgb->maxThreads to be equal to zero in order to allow clients to zero initialize the avifRGBImage struct
// with memset.
if (!image->yuvPlanes[AVIF_CHAN_Y] || rgb->maxThreads < 0) {
return AVIF_RESULT_REFORMAT_FAILED;
}
avifReformatState state;
if (!avifPrepareReformatState(image, rgb, &state)) {
return AVIF_RESULT_REFORMAT_FAILED;
}
avifAlphaMultiplyMode alphaMultiplyMode = AVIF_ALPHA_MULTIPLY_MODE_NO_OP;
if (image->alphaPlane) {
if (!avifRGBFormatHasAlpha(rgb->format) || rgb->ignoreAlpha) {
// if we are converting some image with alpha into a format without alpha, we should do 'premultiply alpha' before
// discarding alpha plane. This has the same effect of rendering this image on a black background, which makes sense.
if (!image->alphaPremultiplied) {
alphaMultiplyMode = AVIF_ALPHA_MULTIPLY_MODE_MULTIPLY;
}
} else {
if (!image->alphaPremultiplied && rgb->alphaPremultiplied) {
alphaMultiplyMode = AVIF_ALPHA_MULTIPLY_MODE_MULTIPLY;
} else if (image->alphaPremultiplied && !rgb->alphaPremultiplied) {
alphaMultiplyMode = AVIF_ALPHA_MULTIPLY_MODE_UNMULTIPLY;
}
}
}
// In practice, we rarely need more than 8 threads for YUV to RGB conversion.
uint32_t jobs = AVIF_CLAMP(rgb->maxThreads, 1, 8);
// When yuv format is 420 and chromaUpsampling could be BILINEAR, there is a dependency across the horizontal borders of each
// job. So we disallow multithreading in that case.
if (image->yuvFormat == AVIF_PIXEL_FORMAT_YUV420 && (rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_AUTOMATIC ||
rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_BEST_QUALITY ||
rgb->chromaUpsampling == AVIF_CHROMA_UPSAMPLING_BILINEAR)) {
jobs = 1;
}
// Each thread worker needs at least 2 Y rows (to account for potential U/V subsampling).
if (jobs == 1 || (image->height / 2) < jobs) {
return avifImageYUVToRGBImpl(image, rgb, &state, alphaMultiplyMode);
}
const size_t byteCount = sizeof(YUVToRGBThreadData) * jobs;
YUVToRGBThreadData * threadData = (YUVToRGBThreadData *)avifAlloc(byteCount);
if (!threadData) {
return AVIF_RESULT_OUT_OF_MEMORY;
}
memset(threadData, 0, byteCount);
uint32_t rowsPerJob = image->height / jobs;
if (rowsPerJob % 2) {
++rowsPerJob;
jobs = (image->height + rowsPerJob - 1) / rowsPerJob; // ceil
}
const uint32_t rowsForLastJob = image->height - rowsPerJob * (jobs - 1);
uint32_t startRow = 0;
uint32_t i;
for (i = 0; i < jobs; ++i, startRow += rowsPerJob) {
YUVToRGBThreadData * tdata = &threadData[i];
const avifCropRect rect = { .x = 0, .y = startRow, .width = image->width, .height = (i == jobs - 1) ? rowsForLastJob : rowsPerJob };
if (avifImageSetViewRect(&tdata->image, image, &rect) != AVIF_RESULT_OK) {
tdata->result = AVIF_RESULT_REFORMAT_FAILED;
break;
}
tdata->rgb = *rgb;
tdata->rgb.pixels += startRow * (size_t)rgb->rowBytes;
tdata->rgb.height = tdata->image.height;
tdata->state = &state;
tdata->alphaMultiplyMode = alphaMultiplyMode;
if (i > 0) {
tdata->threadCreated = avifCreateYUVToRGBThread(tdata);
if (!tdata->threadCreated) {
tdata->result = AVIF_RESULT_REFORMAT_FAILED;
break;
}
}
}
// If above loop ran successfully, run the first job in the current thread.
if (i == jobs) {
avifImageYUVToRGBThreadWorker(&threadData[0]);
}
avifResult result = AVIF_RESULT_OK;
for (i = 0; i < jobs; ++i) {
YUVToRGBThreadData * tdata = &threadData[i];
if (tdata->threadCreated && !avifJoinYUVToRGBThread(tdata)) {
result = AVIF_RESULT_REFORMAT_FAILED;
}
if (tdata->result != AVIF_RESULT_OK) {
result = tdata->result;
}
}
avifFree(threadData);
return result;
}
// Limited -> Full
// Plan: subtract limited offset, then multiply by ratio of FULLSIZE/LIMITEDSIZE (rounding), then clamp.
// RATIO = (FULLY - 0) / (MAXLIMITEDY - MINLIMITEDY)
// -----------------------------------------
// ( ( (v - MINLIMITEDY) | subtract limited offset
// * FULLY | multiply numerator of ratio
// ) + ((MAXLIMITEDY - MINLIMITEDY) / 2) | add 0.5 (half of denominator) to round
// ) / (MAXLIMITEDY - MINLIMITEDY) | divide by denominator of ratio
// AVIF_CLAMP(v, 0, FULLY) | clamp to full range
// -----------------------------------------
#define LIMITED_TO_FULL(MINLIMITEDY, MAXLIMITEDY, FULLY) \
v = (((v - MINLIMITEDY) * FULLY) + ((MAXLIMITEDY - MINLIMITEDY) / 2)) / (MAXLIMITEDY - MINLIMITEDY); \
v = AVIF_CLAMP(v, 0, FULLY)
// Full -> Limited
// Plan: multiply by ratio of LIMITEDSIZE/FULLSIZE (rounding), then add limited offset, then clamp.
// RATIO = (MAXLIMITEDY - MINLIMITEDY) / (FULLY - 0)
// -----------------------------------------
// ( ( (v * (MAXLIMITEDY - MINLIMITEDY)) | multiply numerator of ratio
// + (FULLY / 2) | add 0.5 (half of denominator) to round
// ) / FULLY | divide by denominator of ratio
// ) + MINLIMITEDY | add limited offset
// AVIF_CLAMP(v, MINLIMITEDY, MAXLIMITEDY) | clamp to limited range
// -----------------------------------------
#define FULL_TO_LIMITED(MINLIMITEDY, MAXLIMITEDY, FULLY) \
v = (((v * (MAXLIMITEDY - MINLIMITEDY)) + (FULLY / 2)) / FULLY) + MINLIMITEDY; \
v = AVIF_CLAMP(v, MINLIMITEDY, MAXLIMITEDY)
int avifLimitedToFullY(uint32_t depth, int v)
{
switch (depth) {
case 8:
LIMITED_TO_FULL(16, 235, 255);
break;
case 10:
LIMITED_TO_FULL(64, 940, 1023);
break;
case 12:
LIMITED_TO_FULL(256, 3760, 4095);
break;
}
return v;
}
int avifLimitedToFullUV(uint32_t depth, int v)
{
switch (depth) {
case 8:
LIMITED_TO_FULL(16, 240, 255);
break;
case 10:
LIMITED_TO_FULL(64, 960, 1023);
break;
case 12:
LIMITED_TO_FULL(256, 3840, 4095);
break;
}
return v;
}
int avifFullToLimitedY(uint32_t depth, int v)
{
switch (depth) {
case 8:
FULL_TO_LIMITED(16, 235, 255);
break;
case 10:
FULL_TO_LIMITED(64, 940, 1023);
break;
case 12:
FULL_TO_LIMITED(256, 3760, 4095);
break;
}
return v;
}
int avifFullToLimitedUV(uint32_t depth, int v)
{
switch (depth) {
case 8:
FULL_TO_LIMITED(16, 240, 255);
break;
case 10:
FULL_TO_LIMITED(64, 960, 1023);
break;
case 12:
FULL_TO_LIMITED(256, 3840, 4095);
break;
}
return v;
}
static inline uint16_t avifFloatToF16(float v)
{
avifF16 f16;
f16.f = v * F16_MULTIPLIER;
return (uint16_t)(f16.u32 >> 13);
}
static inline float avifF16ToFloat(uint16_t v)
{
avifF16 f16;
f16.u32 = v << 13;
return f16.f / F16_MULTIPLIER;
}
void avifGetRGBAPixel(const avifRGBImage * src, uint32_t x, uint32_t y, const avifRGBColorSpaceInfo * info, float rgbaPixel[4])
{
assert(src != NULL);
assert(!src->isFloat || src->depth == 16);
assert(src->format != AVIF_RGB_FORMAT_RGB_565 || src->depth == 8);
const uint8_t * const srcPixel = &src->pixels[y * src->rowBytes + x * info->pixelBytes];
if (info->channelBytes > 1) {
uint16_t r = *((uint16_t *)(&srcPixel[info->offsetBytesR]));
uint16_t g = *((uint16_t *)(&srcPixel[info->offsetBytesG]));
uint16_t b = *((uint16_t *)(&srcPixel[info->offsetBytesB]));
uint16_t a = avifRGBFormatHasAlpha(src->format) ? *((uint16_t *)(&srcPixel[info->offsetBytesA])) : (uint16_t)info->maxChannel;
if (src->isFloat) {
rgbaPixel[0] = avifF16ToFloat(r);
rgbaPixel[1] = avifF16ToFloat(g);
rgbaPixel[2] = avifF16ToFloat(b);
rgbaPixel[3] = avifRGBFormatHasAlpha(src->format) ? avifF16ToFloat(a) : 1.0f;
} else {
rgbaPixel[0] = r / info->maxChannelF;
rgbaPixel[1] = g / info->maxChannelF;
rgbaPixel[2] = b / info->maxChannelF;
rgbaPixel[3] = a / info->maxChannelF;
}
} else {
if (src->format == AVIF_RGB_FORMAT_RGB_565) {
uint8_t r, g, b;
avifGetRGB565(&srcPixel[info->offsetBytesR], &r, &g, &b);
rgbaPixel[0] = r / info->maxChannelF;
rgbaPixel[1] = g / info->maxChannelF;
rgbaPixel[2] = b / info->maxChannelF;
rgbaPixel[3] = 1.0f;
} else {
rgbaPixel[0] = srcPixel[info->offsetBytesR] / info->maxChannelF;
rgbaPixel[1] = srcPixel[info->offsetBytesG] / info->maxChannelF;
rgbaPixel[2] = srcPixel[info->offsetBytesB] / info->maxChannelF;
rgbaPixel[3] = avifRGBFormatHasAlpha(src->format) ? (srcPixel[info->offsetBytesA] / info->maxChannelF) : 1.0f;
}
}
}
void avifSetRGBAPixel(const avifRGBImage * dst, uint32_t x, uint32_t y, const avifRGBColorSpaceInfo * info, const float rgbaPixel[4])
{
assert(dst != NULL);
assert(!dst->isFloat || dst->depth == 16);
assert(dst->format != AVIF_RGB_FORMAT_RGB_565 || dst->depth == 8);
assert(rgbaPixel[0] >= 0.0f && rgbaPixel[0] <= 1.0f);
assert(rgbaPixel[1] >= 0.0f && rgbaPixel[1] <= 1.0f);
assert(rgbaPixel[2] >= 0.0f && rgbaPixel[2] <= 1.0f);
uint8_t * const dstPixel = &dst->pixels[y * dst->rowBytes + x * info->pixelBytes];
uint8_t * const ptrR = &dstPixel[info->offsetBytesR];
uint8_t * const ptrG = &dstPixel[info->offsetBytesG];
uint8_t * const ptrB = &dstPixel[info->offsetBytesB];
uint8_t * const ptrA = avifRGBFormatHasAlpha(dst->format) ? &dstPixel[info->offsetBytesA] : NULL;
if (dst->depth > 8) {
if (dst->isFloat) {
*((uint16_t *)ptrR) = avifFloatToF16(rgbaPixel[0]);
*((uint16_t *)ptrG) = avifFloatToF16(rgbaPixel[1]);
*((uint16_t *)ptrB) = avifFloatToF16(rgbaPixel[2]);
if (ptrA) {
*((uint16_t *)ptrA) = avifFloatToF16(rgbaPixel[3]);
}
} else {
*((uint16_t *)ptrR) = (uint16_t)(0.5f + (rgbaPixel[0] * info->maxChannelF));
*((uint16_t *)ptrG) = (uint16_t)(0.5f + (rgbaPixel[1] * info->maxChannelF));
*((uint16_t *)ptrB) = (uint16_t)(0.5f + (rgbaPixel[2] * info->maxChannelF));
if (ptrA) {
*((uint16_t *)ptrA) = (uint16_t)(0.5f + (rgbaPixel[3] * info->maxChannelF));
}
}
} else {
avifStoreRGB8Pixel(dst->format,
(uint8_t)(0.5f + (rgbaPixel[0] * info->maxChannelF)),
(uint8_t)(0.5f + (rgbaPixel[1] * info->maxChannelF)),
(uint8_t)(0.5f + (rgbaPixel[2] * info->maxChannelF)),
ptrR,
ptrG,
ptrB);
if (ptrA) {
*ptrA = (uint8_t)(0.5f + (rgbaPixel[3] * info->maxChannelF));
}
}
}