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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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25
sharpyuv/sharpyuv.h
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@@ -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,
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 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,
const SharpYuvConversionMatrix* yuv_matrix);
#ifdef __cplusplus
} // extern "C"