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Let SharpArgbToYuv caller pass in an RGB>YUV conversion matrix.

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Change-Id: I4ed2dfc00ce63361abd49c693f31f307e0b0262f
This commit is contained in:
Maryla 2022-03-21 11:27:39 +01:00
parent 34bb332ca1
commit 7a68afaac5
3 changed files with 59 additions and 37 deletions
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55
sharpyuv/sharpyuv.c
View File

@ -252,25 +252,18 @@ static void InterpolateTwoRows(const fixed_y_t* const best_y,
}
}
static WEBP_INLINE uint8_t ConvertRGBToY(int r, int g, int b) {
const int luma = 16839 * r + 33059 * g + 6420 * b + SROUNDER;
return clip_8b(16 + (luma >> (YUV_FIX + SFIX)));
}
static WEBP_INLINE uint8_t ConvertRGBToU(int r, int g, int b) {
const int u = -9719 * r - 19081 * g + 28800 * b + SROUNDER;
return clip_8b(128 + (u >> (YUV_FIX + SFIX)));
}
static WEBP_INLINE uint8_t ConvertRGBToV(int r, int g, int b) {
const int v = +28800 * r - 24116 * g - 4684 * b + SROUNDER;
return clip_8b(128 + (v >> (YUV_FIX + SFIX)));
static WEBP_INLINE uint8_t RGBToYUVComponent(int r, int g, int b,
const int coeffs[4]) {
const int luma = coeffs[0] * r + coeffs[1] * g + coeffs[2] * b +
(coeffs[3] << SFIX) + SROUNDER;
return clip_8b((luma >> (YUV_FIX + SFIX)));
}
static int ConvertWRGBToYUV(const fixed_y_t* best_y, const fixed_t* best_uv,
uint8_t* dst_y, int dst_stride_y, uint8_t* dst_u,
int dst_stride_u, uint8_t* dst_v, int dst_stride_v,
int width, int height) {
int width, int height,
const SharpYuvConversionMatrix* yuv_matrix) {
int i, j;
const fixed_t* const best_uv_base = best_uv;
const int w = (width + 1) & ~1;
@ -284,7 +277,7 @@ static int ConvertWRGBToYUV(const fixed_y_t* best_y, const fixed_t* best_uv,
const int r = best_uv[off + 0 * uv_w] + W;
const int g = best_uv[off + 1 * uv_w] + W;
const int b = best_uv[off + 2 * uv_w] + W;
dst_y[i] = ConvertRGBToY(r, g, b);
dst_y[i] = RGBToYUVComponent(r, g, b, yuv_matrix->rgb_to_y);
}
best_y += w;
best_uv += (j & 1) * 3 * uv_w;
@ -296,8 +289,8 @@ static int ConvertWRGBToYUV(const fixed_y_t* best_y, const fixed_t* best_uv,
const int r = best_uv[off + 0 * uv_w];
const int g = best_uv[off + 1 * uv_w];
const int b = best_uv[off + 2 * uv_w];
dst_u[i] = ConvertRGBToU(r, g, b);
dst_v[i] = ConvertRGBToV(r, g, b);
dst_u[i] = RGBToYUVComponent(r, g, b, yuv_matrix->rgb_to_u);
dst_v[i] = RGBToYUVComponent(r, g, b, yuv_matrix->rgb_to_v);
}
best_uv += 3 * uv_w;
dst_u += dst_stride_u;
@ -321,7 +314,8 @@ static int DoSharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
const uint8_t* b_ptr, int step, int rgb_stride,
uint8_t* dst_y, int dst_stride_y, uint8_t* dst_u,
int dst_stride_u, uint8_t* dst_v, int dst_stride_v,
int width, int height) {
int width, int height,
const SharpYuvConversionMatrix* yuv_matrix) {
// we expand the right/bottom border if needed
const int w = (width + 1) & ~1;
const int h = (height + 1) & ~1;
@ -429,7 +423,8 @@ static int DoSharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
}
// final reconstruction
ok = ConvertWRGBToYUV(best_y_base, best_uv_base, dst_y, dst_stride_y, dst_u,
dst_stride_u, dst_v, dst_stride_v, width, height);
dst_stride_u, dst_v, dst_stride_v, width, height,
yuv_matrix);
End:
free(best_y_base);
@ -443,18 +438,30 @@ static int DoSharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
}
#undef SAFE_ALLOC
int SharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
// In YUV_FIX fixed point precision.
static const SharpYuvConversionMatrix kWebpYuvMatrix = {
{16839, 33059, 6420, 16 << 16},
{-9719, -19081, 28800, 128 << 16},
{28800, -24116, -4684, 128 << 16},
};
const SharpYuvConversionMatrix* SharpYuvGetWebpMatrix(void) {
return &kWebpYuvMatrix;
}
int SharpYuvConvert(const uint8_t* r_ptr, const uint8_t* g_ptr,
const uint8_t* b_ptr, int step, int rgb_stride,
uint8_t* dst_y, int dst_stride_y, uint8_t* dst_u,
int dst_stride_u, uint8_t* dst_v, int dst_stride_v,
int width, int height) {
int width, int height,
const SharpYuvConversionMatrix* yuv_matrix) {
if (width < kMinDimensionIterativeConversion ||
height < kMinDimensionIterativeConversion) {
return 0;
}
return DoSharpArgbToYuv(
r_ptr, g_ptr, b_ptr, step, rgb_stride, dst_y, dst_stride_y, dst_u,
dst_stride_u, dst_v, dst_stride_v, width, height);
return DoSharpArgbToYuv(r_ptr, g_ptr, b_ptr, step, rgb_stride, dst_y,
dst_stride_y, dst_u, dst_stride_u, dst_v,
dst_stride_v, width, height, yuv_matrix);
}
//------------------------------------------------------------------------------

19
sharpyuv/sharpyuv.h
View File

@ -18,6 +18,20 @@
extern "C" {
#endif
// RGB to YUV conversion matrix, in 16 bit fixed point.
// y = rgb_to_y[0] * r + rgb_to_y[1] * g + rgb_to_y[2] * b + rgb_to_y[3]
// u = rgb_to_u[0] * r + rgb_to_u[1] * g + rgb_to_u[2] * b + rgb_to_u[3]
// v = rgb_to_v[0] * r + rgb_to_v[1] * g + rgb_to_v[2] * b + rgb_to_v[3]
// Then y, u and v values are divided by 1<<16 and rounded.
typedef struct {
int rgb_to_y[4];
int rgb_to_u[4];
int rgb_to_v[4];
} SharpYuvConversionMatrix;
// Returns the RGB to YUV matrix used by WebP.
const SharpYuvConversionMatrix* SharpYuvGetWebpMatrix(void);
// Converts RGB to YUV420 using a downsampling algorithm that minimizes
// artefacts caused by chroma subsampling.
// This is slower than standard downsampling (averaging of 4 UV values).
@ -27,11 +41,12 @@ extern "C" {
// TODO(maryla): add 10 bits and handling of various colorspaces. Add YUV444 to
// YUV420 conversion. Maybe also add 422 support (it's rarely used in practice,
// especially for images).
int SharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
int SharpYuvConvert(const uint8_t* r_ptr, const uint8_t* g_ptr,
const uint8_t* b_ptr, int step, int rgb_stride,
uint8_t* dst_y, int dst_stride_y, uint8_t* dst_u,
int dst_stride_u, uint8_t* dst_v, int dst_stride_v,
int width, int height);
int width, int height,
const SharpYuvConversionMatrix* yuv_matrix);
#ifdef __cplusplus
} // extern "C"

10
src/enc/picture_csp_enc.c
View File

@ -179,12 +179,12 @@ static int PreprocessARGB(const uint8_t* r_ptr,
const uint8_t* b_ptr,
int step, int rgb_stride,
WebPPicture* const picture) {
int ok = SharpArgbToYuv(r_ptr, g_ptr, b_ptr, step, rgb_stride, picture->y,
picture->y_stride, picture->u, picture->uv_stride,
picture->v, picture->uv_stride, picture->width,
picture->height);
const int ok = SharpYuvConvert(
r_ptr, g_ptr, b_ptr, step, rgb_stride, picture->y, picture->y_stride,
picture->u, picture->uv_stride, picture->v, picture->uv_stride,
picture->width, picture->height, SharpYuvGetWebpMatrix());
if (!ok) {
ok = WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY);
return WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY);
}
return ok;
}