mirror of
https://github.com/webmproject/libwebp.git
synced 2024-12-27 06:08:21 +01:00
Add smart RGB->YUV conversion option -pre 4
New function: WebPPictureSmartARGBToYUVA()
This implement smart RGB->YUV conversion.
This is rather undocumented for now, and is triggered using '-pre 4'
preprocessing option.
This is slow-ish and use quite some memory, but should be improvable.
This is somehow a usable beta version.
(cherry picked from commit 3fc4c539aa)
Change-Id: Ia50a8c30134e4cab8a7d3eb70aef13ce1f6187a1
This commit is contained in:
skal
James Zern
parent
1a161e20a4
commit
21abaa05e3
@ -111,7 +111,7 @@ int WebPValidateConfig(const WebPConfig* config) {
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return 0;
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if (config->show_compressed < 0 || config->show_compressed > 1)
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return 0;
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if (config->preprocessing < 0 || config->preprocessing > 3)
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if (config->preprocessing < 0 || config->preprocessing > 7)
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return 0;
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if (config->partitions < 0 || config->partitions > 3)
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return 0;
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@ -17,6 +17,7 @@
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#include "./vp8enci.h"
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#include "../utils/random.h"
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#include "../utils/utils.h"
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#include "../dsp/yuv.h"
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// Uncomment to disable gamma-compression during RGB->U/V averaging
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@ -69,6 +70,70 @@ int WebPPictureHasTransparency(const WebPPicture* picture) {
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return 0;
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}
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//------------------------------------------------------------------------------
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// Code for gamma correction
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#if defined(USE_GAMMA_COMPRESSION)
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// gamma-compensates loss of resolution during chroma subsampling
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#define kGamma 0.80 // for now we use a different gamma value than kGammaF
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#define kGammaFix 12 // fixed-point precision for linear values
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#define kGammaScale ((1 << kGammaFix) - 1)
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#define kGammaTabFix 7 // fixed-point fractional bits precision
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#define kGammaTabScale (1 << kGammaTabFix)
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#define kGammaTabRounder (kGammaTabScale >> 1)
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#define kGammaTabSize (1 << (kGammaFix - kGammaTabFix))
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static int kLinearToGammaTab[kGammaTabSize + 1];
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static uint16_t kGammaToLinearTab[256];
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static int kGammaTablesOk = 0;
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static void InitGammaTables(void) {
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if (!kGammaTablesOk) {
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int v;
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const double scale = (double)(1 << kGammaTabFix) / kGammaScale;
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const double norm = 1. / 255.;
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for (v = 0; v <= 255; ++v) {
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kGammaToLinearTab[v] =
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(uint16_t)(pow(norm * v, kGamma) * kGammaScale + .5);
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}
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for (v = 0; v <= kGammaTabSize; ++v) {
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kLinearToGammaTab[v] = (int)(255. * pow(scale * v, 1. / kGamma) + .5);
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}
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kGammaTablesOk = 1;
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}
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}
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static WEBP_INLINE uint32_t GammaToLinear(uint8_t v) {
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return kGammaToLinearTab[v];
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}
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static WEBP_INLINE int Interpolate(int v) {
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const int tab_pos = v >> (kGammaTabFix + 2); // integer part
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const int x = v & ((kGammaTabScale << 2) - 1); // fractional part
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const int v0 = kLinearToGammaTab[tab_pos];
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const int v1 = kLinearToGammaTab[tab_pos + 1];
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const int y = v1 * x + v0 * ((kGammaTabScale << 2) - x); // interpolate
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return y;
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}
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// Convert a linear value 'v' to YUV_FIX+2 fixed-point precision
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// U/V value, suitable for RGBToU/V calls.
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static WEBP_INLINE int LinearToGamma(uint32_t base_value, int shift) {
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const int y = Interpolate(base_value << shift); // final uplifted value
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return (y + kGammaTabRounder) >> kGammaTabFix; // descale
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}
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#else
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static void InitGammaTables(void) {}
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static WEBP_INLINE uint32_t GammaToLinear(uint8_t v) { return v; }
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static WEBP_INLINE int LinearToGamma(uint32_t base_value, int shift) {
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return (int)(base_value << shift);
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}
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#endif // USE_GAMMA_COMPRESSION
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//------------------------------------------------------------------------------
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// RGB -> YUV conversion
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@ -85,66 +150,418 @@ static int RGBToV(int r, int g, int b, VP8Random* const rg) {
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}
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//------------------------------------------------------------------------------
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// Smart RGB->YUV conversion
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static const int kNumIterations = 6;
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// We use a-priori a different precision for storing RGB and Y/W components
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// We could use YFIX=0 and only uint8_t for fixed_y_t, but it produces some
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// banding sometimes. Better use extra precision.
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// TODO(skal): cleanup once TFIX/YFIX values are fixed.
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typedef int16_t fixed_t; // signed type with extra TFIX precision for UV
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typedef uint16_t fixed_y_t; // unsigned type with extra YFIX precision for W
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#define TFIX 6 // fixed-point precision of RGB
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#define YFIX 2 // fixed point precision for Y/W
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#define THALF ((1 << TFIX) >> 1)
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#define MAX_Y_T ((256 << YFIX) - 1)
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#define TROUNDER (1 << (YUV_FIX + TFIX - 1))
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#if defined(USE_GAMMA_COMPRESSION)
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// gamma-compensates loss of resolution during chroma subsampling
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#define kGamma 0.80
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#define kGammaFix 12 // fixed-point precision for linear values
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#define kGammaScale ((1 << kGammaFix) - 1)
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#define kGammaTabFix 7 // fixed-point fractional bits precision
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#define kGammaTabScale (1 << kGammaTabFix)
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#define kGammaTabRounder (kGammaTabScale >> 1)
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#define kGammaTabSize (1 << (kGammaFix - kGammaTabFix))
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// float variant of gamma-correction
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// We use tables of different size and precision, along with a 'real-world'
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// Gamma value close to ~2.
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#define kGammaF 2.2
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static float kGammaToLinearTabF[MAX_Y_T + 1]; // size scales with Y_FIX
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static float kLinearToGammaTabF[kGammaTabSize + 2];
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static int kGammaTablesFOk = 0;
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static int kLinearToGammaTab[kGammaTabSize + 1];
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static uint16_t kGammaToLinearTab[256];
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static int kGammaTablesOk = 0;
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static void InitGammaTables(void) {
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if (!kGammaTablesOk) {
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static void InitGammaTablesF(void) {
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if (!kGammaTablesFOk) {
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int v;
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const double scale = 1. / kGammaScale;
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for (v = 0; v <= 255; ++v) {
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kGammaToLinearTab[v] =
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(uint16_t)(pow(v / 255., kGamma) * kGammaScale + .5);
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const double norm = 1. / MAX_Y_T;
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const double scale = 1. / kGammaTabSize;
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for (v = 0; v <= MAX_Y_T; ++v) {
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kGammaToLinearTabF[v] = (float)pow(norm * v, kGammaF);
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}
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for (v = 0; v <= kGammaTabSize; ++v) {
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const double x = scale * (v << kGammaTabFix);
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kLinearToGammaTab[v] = (int)(pow(x, 1. / kGamma) * 255. + .5);
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kLinearToGammaTabF[v] = (float)(MAX_Y_T * pow(scale * v, 1. / kGammaF));
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}
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kGammaTablesOk = 1;
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// to prevent small rounding errors to cause read-overflow:
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kLinearToGammaTabF[kGammaTabSize + 1] = kLinearToGammaTabF[kGammaTabSize];
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kGammaTablesFOk = 1;
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}
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}
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static WEBP_INLINE uint32_t GammaToLinear(uint8_t v) {
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return kGammaToLinearTab[v];
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static WEBP_INLINE float GammaToLinearF(int v) {
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return kGammaToLinearTabF[v];
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}
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// Convert a linear value 'v' to YUV_FIX+2 fixed-point precision
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// U/V value, suitable for RGBToU/V calls.
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static WEBP_INLINE int LinearToGamma(uint32_t base_value, int shift) {
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const int v = base_value << shift; // final uplifted value
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const int tab_pos = v >> (kGammaTabFix + 2); // integer part
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const int x = v & ((kGammaTabScale << 2) - 1); // fractional part
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const int v0 = kLinearToGammaTab[tab_pos];
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const int v1 = kLinearToGammaTab[tab_pos + 1];
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const int y = v1 * x + v0 * ((kGammaTabScale << 2) - x); // interpolate
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return (y + kGammaTabRounder) >> kGammaTabFix; // descale
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static WEBP_INLINE float LinearToGammaF(float value) {
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const float v = value * kGammaTabSize;
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const int tab_pos = (int)v;
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const float x = v - (float)tab_pos; // fractional part
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const float v0 = kLinearToGammaTabF[tab_pos + 0];
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const float v1 = kLinearToGammaTabF[tab_pos + 1];
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const float y = v1 * x + v0 * (1. - x); // interpolate
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return y;
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}
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#else
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static void InitGammaTables(void) {}
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static WEBP_INLINE uint32_t GammaToLinear(uint8_t v) { return v; }
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static WEBP_INLINE int LinearToGamma(uint32_t base_value, int shift) {
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return (int)(base_value << shift);
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static void InitGammaTablesF(void) {}
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static WEBP_INLINE float GammaToLinearF(int v) {
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const float norm = 1.f / MAX_Y_T;
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return norm * v;
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}
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static WEBP_INLINE float LinearToGammaF(float value) {
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return MAX_Y_T * value;
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}
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#endif // USE_GAMMA_COMPRESSION
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//------------------------------------------------------------------------------
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// precision: YFIX -> TFIX
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static WEBP_INLINE int FixedYToW(int v) {
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#if TFIX == YFIX
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return v;
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#elif TFIX >= YFIX
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return v << (TFIX - YFIX);
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#else
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return v >> (YFIX - TFIX);
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#endif
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}
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static WEBP_INLINE int FixedWToY(int v) {
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#if TFIX == YFIX
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return v;
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#elif YFIX >= TFIX
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return v << (YFIX - TFIX);
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#else
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return v >> (TFIX - YFIX);
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#endif
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}
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static uint8_t clip_8b(fixed_t v) {
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return (!(v & ~0xff)) ? (uint8_t)v : (v < 0) ? 0u : 255u;
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}
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static fixed_y_t clip_y(int y) {
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return (!(y & ~MAX_Y_T)) ? (fixed_y_t)y : (y < 0) ? 0 : MAX_Y_T;
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}
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// precision: TFIX -> YFIX
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static fixed_y_t clip_fixed_t(fixed_t v) {
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const int y = FixedWToY(v);
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const fixed_y_t w = clip_y(y);
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return w;
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}
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//------------------------------------------------------------------------------
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static int RGBToGray(int r, int g, int b) {
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const int luma = 19595 * r + 38470 * g + 7471 * b + YUV_HALF;
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return (luma >> YUV_FIX);
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}
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static float RGBToGrayF(float r, float g, float b) {
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return 0.299f * r + 0.587f * g + 0.114f * b;
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}
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static float ScaleDown(int a, int b, int c, int d) {
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const float A = GammaToLinearF(a);
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const float B = GammaToLinearF(b);
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const float C = GammaToLinearF(c);
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const float D = GammaToLinearF(d);
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return LinearToGammaF(0.25f * (A + B + C + D));
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}
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static WEBP_INLINE void UpdateW(const fixed_y_t* src, fixed_y_t* dst, int len) {
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while (len-- > 0) {
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const float R = GammaToLinearF(src[0]);
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const float G = GammaToLinearF(src[1]);
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const float B = GammaToLinearF(src[2]);
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const float Y = RGBToGrayF(R, G, B);
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*dst++ = (fixed_y_t)(LinearToGammaF(Y) + .5);
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src += 3;
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}
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}
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static WEBP_INLINE void UpdateChroma(const fixed_y_t* src1,
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const fixed_y_t* src2,
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fixed_t* dst, fixed_y_t* tmp, int len) {
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while (len--> 0) {
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const float r = ScaleDown(src1[0], src1[3], src2[0], src2[3]);
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const float g = ScaleDown(src1[1], src1[4], src2[1], src2[4]);
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const float b = ScaleDown(src1[2], src1[5], src2[2], src2[5]);
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const float W = RGBToGrayF(r, g, b);
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dst[0] = (fixed_t)FixedYToW(r - W);
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dst[1] = (fixed_t)FixedYToW(g - W);
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dst[2] = (fixed_t)FixedYToW(b - W);
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dst += 3;
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src1 += 6;
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src2 += 6;
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if (tmp != NULL) {
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tmp[0] = tmp[1] = clip_y((int)(W + .5));
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tmp += 2;
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}
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}
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}
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//------------------------------------------------------------------------------
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static WEBP_INLINE int Filter(const fixed_t* const A, const fixed_t* const B,
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int rightwise) {
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int v;
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if (!rightwise) {
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v = (A[0] * 9 + A[-3] * 3 + B[0] * 3 + B[-3]);
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} else {
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v = (A[0] * 9 + A[+3] * 3 + B[0] * 3 + B[+3]);
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}
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return (v + 8) >> 4;
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}
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static WEBP_INLINE int Filter2(int A, int B) { return (A * 3 + B + 2) >> 2; }
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//------------------------------------------------------------------------------
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// 8bit -> YFIX
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static WEBP_INLINE fixed_y_t UpLift(uint8_t a) {
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return ((fixed_y_t)a << YFIX) | (1 << (YFIX - 1));
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}
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static void ImportOneRow(const uint8_t* const r_ptr,
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const uint8_t* const g_ptr,
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const uint8_t* const b_ptr,
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int step,
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int pic_width,
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fixed_y_t* const dst) {
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int i;
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for (i = 0; i < pic_width; ++i) {
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const int off = i * step;
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dst[3 * i + 0] = UpLift(r_ptr[off]);
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dst[3 * i + 1] = UpLift(g_ptr[off]);
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dst[3 * i + 2] = UpLift(b_ptr[off]);
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}
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}
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static void InterpolateTwoRows(const fixed_y_t* const best_y,
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const fixed_t* const prev_uv,
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const fixed_t* const cur_uv,
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const fixed_t* const next_uv,
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int w,
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fixed_y_t* const out1,
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fixed_y_t* const out2) {
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int i, k;
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{ // special boundary case for i==0
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const int W0 = FixedYToW(best_y[0]);
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const int W1 = FixedYToW(best_y[w]);
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for (k = 0; k <= 2; ++k) {
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out1[k] = clip_fixed_t(Filter2(cur_uv[k], prev_uv[k]) + W0);
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out2[k] = clip_fixed_t(Filter2(cur_uv[k], next_uv[k]) + W1);
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}
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}
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for (i = 1; i < w - 1; ++i) {
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const int W0 = FixedYToW(best_y[i + 0]);
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const int W1 = FixedYToW(best_y[i + w]);
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const int off = 3 * (i >> 1);
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for (k = 0; k <= 2; ++k) {
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const int tmp0 = Filter(cur_uv + off + k, prev_uv + off + k, i & 1);
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const int tmp1 = Filter(cur_uv + off + k, next_uv + off + k, i & 1);
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out1[3 * i + k] = clip_fixed_t(tmp0 + W0);
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out2[3 * i + k] = clip_fixed_t(tmp1 + W1);
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}
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}
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{ // special boundary case for i == w - 1
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const int W0 = FixedYToW(best_y[i + 0]);
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const int W1 = FixedYToW(best_y[i + w]);
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const int off = 3 * (i >> 1);
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for (k = 0; k <= 2; ++k) {
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out1[3 * i + k] =
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clip_fixed_t(Filter2(cur_uv[off + k], prev_uv[off + k]) + W0);
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out2[3 * i + k] =
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clip_fixed_t(Filter2(cur_uv[off + k], next_uv[off + k]) + W1);
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}
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}
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}
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static WEBP_INLINE uint8_t ConvertRGBToY(int r, int g, int b) {
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const int luma = 16839 * r + 33059 * g + 6420 * b + TROUNDER;
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return clip_8b(16 + (luma >> (YUV_FIX + TFIX)));
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}
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static WEBP_INLINE uint8_t ConvertRGBToU(int r, int g, int b) {
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const int u = -9719 * r - 19081 * g + 28800 * b + TROUNDER;
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return clip_8b(128 + (u >> (YUV_FIX + TFIX)));
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}
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static WEBP_INLINE uint8_t ConvertRGBToV(int r, int g, int b) {
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const int v = +28800 * r - 24116 * g - 4684 * b + TROUNDER;
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return clip_8b(128 + (v >> (YUV_FIX + TFIX)));
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}
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static int ConvertWRGBToYUV(const fixed_y_t* const best_y,
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const fixed_t* const best_uv,
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WebPPicture* const picture) {
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int i, j;
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const int w = (picture->width + 1) & ~1;
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const int h = (picture->height + 1) & ~1;
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const int uv_w = w >> 1;
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const int uv_h = h >> 1;
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for (j = 0; j < picture->height; ++j) {
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for (i = 0; i < picture->width; ++i) {
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const int off = 3 * ((i >> 1) + (j >> 1) * uv_w);
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const int off2 = i + j * picture->y_stride;
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const int W = FixedYToW(best_y[i + j * w]);
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const int r = best_uv[off + 0] + W;
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const int g = best_uv[off + 1] + W;
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const int b = best_uv[off + 2] + W;
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picture->y[off2] = ConvertRGBToY(r, g, b);
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}
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}
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for (j = 0; j < uv_h; ++j) {
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uint8_t* const dst_u = picture->u + j * picture->uv_stride;
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uint8_t* const dst_v = picture->v + j * picture->uv_stride;
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for (i = 0; i < uv_w; ++i) {
|
||||
const int off = 3 * (i + j * uv_w);
|
||||
const int r = best_uv[off + 0];
|
||||
const int g = best_uv[off + 1];
|
||||
const int b = best_uv[off + 2];
|
||||
dst_u[i] = ConvertRGBToU(r, g, b);
|
||||
dst_v[i] = ConvertRGBToV(r, g, b);
|
||||
}
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
||||
//------------------------------------------------------------------------------
|
||||
// Main function
|
||||
|
||||
#define SAFE_ALLOC(W, H, T) ((T*)WebPSafeMalloc((W) * (H), sizeof(T)))
|
||||
|
||||
static int PreprocessARGB(const uint8_t* const r_ptr,
|
||||
const uint8_t* const g_ptr,
|
||||
const uint8_t* const b_ptr,
|
||||
int step, int rgb_stride,
|
||||
WebPPicture* const picture) {
|
||||
// we expand the right/bottom border if needed
|
||||
const int w = (picture->width + 1) & ~1;
|
||||
const int h = (picture->height + 1) & ~1;
|
||||
const int uv_w = w >> 1;
|
||||
const int uv_h = h >> 1;
|
||||
int i, j, iter;
|
||||
|
||||
// TODO(skal): allocate one big memory chunk. But for now, it's easier
|
||||
// for valgrind debugging to have several chunks.
|
||||
fixed_y_t* const tmp_buffer = SAFE_ALLOC(w * 3, 2, fixed_y_t); // scratch
|
||||
fixed_y_t* const best_y = SAFE_ALLOC(w, h, fixed_y_t);
|
||||
fixed_y_t* const target_y = SAFE_ALLOC(w, h, fixed_y_t);
|
||||
fixed_y_t* const best_rgb_y = SAFE_ALLOC(w, 2, fixed_y_t);
|
||||
fixed_t* const best_uv = SAFE_ALLOC(uv_w * 3, uv_h, fixed_t);
|
||||
fixed_t* const target_uv = SAFE_ALLOC(uv_w * 3, uv_h, fixed_t);
|
||||
fixed_t* const best_rgb_uv = SAFE_ALLOC(uv_w * 3, 1, fixed_t);
|
||||
int ok;
|
||||
|
||||
if (best_y == NULL || best_uv == NULL ||
|
||||
target_y == NULL || target_uv == NULL ||
|
||||
best_rgb_y == NULL || best_rgb_uv == NULL ||
|
||||
tmp_buffer == NULL) {
|
||||
ok = WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY);
|
||||
goto End;
|
||||
}
|
||||
|
||||
// Import RGB samples to W/RGB representation.
|
||||
for (j = 0; j < picture->height; j += 2) {
|
||||
const int is_last_row = (j == picture->height - 1);
|
||||
fixed_y_t* const src1 = tmp_buffer;
|
||||
fixed_y_t* const src2 = tmp_buffer + 3 * w;
|
||||
const int off1 = j * rgb_stride;
|
||||
const int off2 = off1 + rgb_stride;
|
||||
const int uv_off = (j >> 1) * 3 * uv_w;
|
||||
fixed_y_t* const dst_y = best_y + j * w;
|
||||
|
||||
// prepare two rows of input
|
||||
ImportOneRow(r_ptr + off1, g_ptr + off1, b_ptr + off1,
|
||||
step, picture->width, src1);
|
||||
if (!is_last_row) {
|
||||
ImportOneRow(r_ptr + off2, g_ptr + off2, b_ptr + off2,
|
||||
step, picture->width, src2);
|
||||
} else {
|
||||
memcpy(src2, src1, 3 * w * sizeof(*src2));
|
||||
}
|
||||
UpdateW(src1, target_y + (j + 0) * w, w);
|
||||
UpdateW(src2, target_y + (j + 1) * w, w);
|
||||
UpdateChroma(src1, src2, target_uv + uv_off, dst_y, uv_w);
|
||||
memcpy(best_uv + uv_off, target_uv + uv_off, 3 * uv_w * sizeof(*best_uv));
|
||||
memcpy(dst_y + w, dst_y, w * sizeof(*dst_y));
|
||||
}
|
||||
|
||||
// Iterate and resolve clipping conflicts.
|
||||
for (iter = 0; iter < kNumIterations; ++iter) {
|
||||
int k;
|
||||
const fixed_t* cur_uv = best_uv;
|
||||
const fixed_t* prev_uv = best_uv;
|
||||
for (j = 0; j < h; j += 2) {
|
||||
fixed_y_t* const src1 = tmp_buffer;
|
||||
fixed_y_t* const src2 = tmp_buffer + 3 * w;
|
||||
|
||||
{
|
||||
const fixed_t* const next_uv = cur_uv + ((j < h - 2) ? 3 * uv_w : 0);
|
||||
InterpolateTwoRows(best_y + j * w, prev_uv, cur_uv, next_uv,
|
||||
w, src1, src2);
|
||||
prev_uv = cur_uv;
|
||||
cur_uv = next_uv;
|
||||
}
|
||||
|
||||
UpdateW(src1, best_rgb_y + 0 * w, w);
|
||||
UpdateW(src2, best_rgb_y + 1 * w, w);
|
||||
UpdateChroma(src1, src2, best_rgb_uv, NULL, uv_w);
|
||||
|
||||
// update two rows of Y and one row of RGB
|
||||
for (i = 0; i < 2 * w; ++i) {
|
||||
const int off = i + j * w;
|
||||
const int diff_y = target_y[off] - best_rgb_y[i];
|
||||
const int new_y = (int)best_y[off] + diff_y;
|
||||
best_y[off] = clip_y(new_y);
|
||||
}
|
||||
for (i = 0; i < uv_w; ++i) {
|
||||
const int off = 3 * (i + (j >> 1) * uv_w);
|
||||
int W;
|
||||
for (k = 0; k <= 2; ++k) {
|
||||
const int diff_uv = (int)target_uv[off + k] - best_rgb_uv[3 * i + k];
|
||||
best_uv[off + k] += diff_uv;
|
||||
}
|
||||
W = RGBToGray(best_uv[off + 0], best_uv[off + 1], best_uv[off + 2]);
|
||||
for (k = 0; k <= 2; ++k) {
|
||||
best_uv[off + k] -= W;
|
||||
}
|
||||
}
|
||||
}
|
||||
// TODO(skal): add early-termination criterion
|
||||
}
|
||||
|
||||
// final reconstruction
|
||||
ok = ConvertWRGBToYUV(best_y, best_uv, picture);
|
||||
|
||||
End:
|
||||
WebPSafeFree(best_y);
|
||||
WebPSafeFree(best_uv);
|
||||
WebPSafeFree(target_y);
|
||||
WebPSafeFree(target_uv);
|
||||
WebPSafeFree(best_rgb_y);
|
||||
WebPSafeFree(best_rgb_uv);
|
||||
WebPSafeFree(tmp_buffer);
|
||||
return ok;
|
||||
}
|
||||
#undef SAFE_ALLOC
|
||||
|
||||
//------------------------------------------------------------------------------
|
||||
// "Fast" regular RGB->YUV
|
||||
|
||||
#define SUM4(ptr) LinearToGamma( \
|
||||
GammaToLinear((ptr)[0]) + \
|
||||
GammaToLinear((ptr)[step]) + \
|
||||
@ -175,23 +592,29 @@ static int ImportYUVAFromRGBA(const uint8_t* const r_ptr,
|
||||
int step, // bytes per pixel
|
||||
int rgb_stride, // bytes per scanline
|
||||
float dithering,
|
||||
int use_iterative_conversion,
|
||||
WebPPicture* const picture) {
|
||||
int x, y;
|
||||
const int width = picture->width;
|
||||
const int height = picture->height;
|
||||
const int has_alpha = CheckNonOpaque(a_ptr, width, height, step, rgb_stride);
|
||||
VP8Random rg;
|
||||
|
||||
if (has_alpha) {
|
||||
picture->colorspace |= WEBP_CSP_ALPHA_BIT;
|
||||
} else {
|
||||
picture->colorspace &= WEBP_CSP_UV_MASK;
|
||||
}
|
||||
picture->colorspace = has_alpha ? WEBP_YUV420A : WEBP_YUV420;
|
||||
picture->use_argb = 0;
|
||||
|
||||
if (!WebPPictureAllocYUVA(picture, width, height)) return 0;
|
||||
if (!WebPPictureAllocYUVA(picture, width, height)) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (use_iterative_conversion) {
|
||||
InitGammaTablesF();
|
||||
if (!PreprocessARGB(r_ptr, g_ptr, b_ptr, step, rgb_stride, picture)) {
|
||||
return 0;
|
||||
}
|
||||
} else {
|
||||
VP8Random rg;
|
||||
VP8InitRandom(&rg, dithering);
|
||||
|
||||
InitGammaTables();
|
||||
|
||||
// Import luma plane
|
||||
@ -220,6 +643,7 @@ static int ImportYUVAFromRGBA(const uint8_t* const r_ptr,
|
||||
RGB_TO_UV(x, y, SUM1);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (has_alpha) {
|
||||
assert(step >= 4);
|
||||
@ -243,11 +667,13 @@ static int ImportYUVAFromRGBA(const uint8_t* const r_ptr,
|
||||
//------------------------------------------------------------------------------
|
||||
// call for ARGB->YUVA conversion
|
||||
|
||||
int WebPPictureARGBToYUVADithered(WebPPicture* picture, WebPEncCSP colorspace,
|
||||
float dithering) {
|
||||
static int PictureARGBToYUVA(WebPPicture* picture, WebPEncCSP colorspace,
|
||||
float dithering, int use_iterative_conversion) {
|
||||
if (picture == NULL) return 0;
|
||||
if (picture->argb == NULL) {
|
||||
return WebPEncodingSetError(picture, VP8_ENC_ERROR_NULL_PARAMETER);
|
||||
} else if ((colorspace & WEBP_CSP_UV_MASK) != WEBP_YUV420) {
|
||||
return WebPEncodingSetError(picture, VP8_ENC_ERROR_INVALID_CONFIGURATION);
|
||||
} else {
|
||||
const uint8_t* const argb = (const uint8_t*)picture->argb;
|
||||
const uint8_t* const r = ALPHA_IS_LAST ? argb + 2 : argb + 1;
|
||||
@ -255,14 +681,23 @@ int WebPPictureARGBToYUVADithered(WebPPicture* picture, WebPEncCSP colorspace,
|
||||
const uint8_t* const b = ALPHA_IS_LAST ? argb + 0 : argb + 3;
|
||||
const uint8_t* const a = ALPHA_IS_LAST ? argb + 3 : argb + 0;
|
||||
|
||||
picture->colorspace = colorspace;
|
||||
picture->colorspace = WEBP_YUV420;
|
||||
return ImportYUVAFromRGBA(r, g, b, a, 4, 4 * picture->argb_stride,
|
||||
dithering, picture);
|
||||
dithering, use_iterative_conversion, picture);
|
||||
}
|
||||
}
|
||||
|
||||
int WebPPictureARGBToYUVADithered(WebPPicture* picture, WebPEncCSP colorspace,
|
||||
float dithering) {
|
||||
return PictureARGBToYUVA(picture, colorspace, dithering, 0);
|
||||
}
|
||||
|
||||
int WebPPictureARGBToYUVA(WebPPicture* picture, WebPEncCSP colorspace) {
|
||||
return WebPPictureARGBToYUVADithered(picture, colorspace, 0.f);
|
||||
return PictureARGBToYUVA(picture, colorspace, 0.f, 0);
|
||||
}
|
||||
|
||||
int WebPPictureSmartARGBToYUVA(WebPPicture* picture) {
|
||||
return PictureARGBToYUVA(picture, WEBP_YUV420, 0.f, 1);
|
||||
}
|
||||
|
||||
//------------------------------------------------------------------------------
|
||||
@ -343,7 +778,7 @@ static int Import(WebPPicture* const picture,
|
||||
|
||||
if (!picture->use_argb) {
|
||||
return ImportYUVAFromRGBA(r_ptr, g_ptr, b_ptr, a_ptr, step, rgb_stride,
|
||||
0.f /* no dithering */, picture);
|
||||
0.f /* no dithering */, 0, picture);
|
||||
}
|
||||
if (!WebPPictureAlloc(picture)) return 0;
|
||||
|
||||
|
||||
@ -328,6 +328,11 @@ int WebPEncode(const WebPConfig* config, WebPPicture* pic) {
|
||||
VP8Encoder* enc = NULL;
|
||||
if (pic->y == NULL || pic->u == NULL || pic->v == NULL) {
|
||||
// Make sure we have YUVA samples.
|
||||
if (config->preprocessing & 4) {
|
||||
if (!WebPPictureSmartARGBToYUVA(pic)) {
|
||||
return 0;
|
||||
}
|
||||
} else {
|
||||
float dithering = 0.f;
|
||||
if (config->preprocessing & 2) {
|
||||
const float x = config->quality / 100.f;
|
||||
@ -340,6 +345,7 @@ int WebPEncode(const WebPConfig* config, WebPPicture* pic) {
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
enc = InitVP8Encoder(config, pic);
|
||||
if (enc == NULL) return 0; // pic->error is already set.
|
||||
|
||||
@ -446,13 +446,14 @@ WEBP_EXTERN(int) WebPPictureImportBGRA(
|
||||
WEBP_EXTERN(int) WebPPictureImportBGRX(
|
||||
WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride);
|
||||
|
||||
// Converts picture->argb data to the YUVA format specified by 'colorspace'.
|
||||
// Converts picture->argb data to the YUV420A format. The 'colorspace'
|
||||
// parameter is deprecated and should be equal to WEBP_YUV420.
|
||||
// Upon return, picture->use_argb is set to false. The presence of real
|
||||
// non-opaque transparent values is detected, and 'colorspace' will be
|
||||
// adjusted accordingly. Note that this method is lossy.
|
||||
// Returns false in case of error.
|
||||
WEBP_EXTERN(int) WebPPictureARGBToYUVA(WebPPicture* picture,
|
||||
WebPEncCSP colorspace);
|
||||
WebPEncCSP /*colorspace = WEBP_YUV420*/);
|
||||
|
||||
// Same as WebPPictureARGBToYUVA(), but the conversion is done using
|
||||
// pseudo-random dithering with a strength 'dithering' between
|
||||
@ -461,6 +462,13 @@ WEBP_EXTERN(int) WebPPictureARGBToYUVA(WebPPicture* picture,
|
||||
WEBP_EXTERN(int) WebPPictureARGBToYUVADithered(
|
||||
WebPPicture* picture, WebPEncCSP colorspace, float dithering);
|
||||
|
||||
// Performs 'smart' RGBA->YUVA420 downsampling and colorspace conversion.
|
||||
// Downsampling is handled with extra care in case of color clipping. This
|
||||
// method is roughly 2x slower than WebPPictureARGBToYUVA() but produces better
|
||||
// YUV representation.
|
||||
// Returns false in case of error.
|
||||
WEBP_EXTERN(int) WebPPictureSmartARGBToYUVA(WebPPicture* picture);
|
||||
|
||||
// Converts picture->yuv to picture->argb and sets picture->use_argb to true.
|
||||
// The input format must be YUV_420 or YUV_420A.
|
||||
// Note that the use of this method is discouraged if one has access to the
|
||||
|
||||
Loading…
Reference in New Issue
Block a user