f3cc601e6c
https://chromium.googlesource.com/webm/libwebp/+/1.3.1/NEWS
(cherry picked from commit 2529ad6a64)
103 lines
4.5 KiB
C++
103 lines
4.5 KiB
C++
// Copyright 2022 Google Inc. All Rights Reserved.
|
|
//
|
|
// Use of this source code is governed by a BSD-style license
|
|
// that can be found in the COPYING file in the root of the source
|
|
// tree. An additional intellectual property rights grant can be found
|
|
// in the file PATENTS. All contributing project authors may
|
|
// be found in the AUTHORS file in the root of the source tree.
|
|
// -----------------------------------------------------------------------------
|
|
//
|
|
// Sharp RGB to YUV conversion.
|
|
|
|
#ifndef WEBP_SHARPYUV_SHARPYUV_H_
|
|
#define WEBP_SHARPYUV_SHARPYUV_H_
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
#ifndef SHARPYUV_EXTERN
|
|
#ifdef WEBP_EXTERN
|
|
#define SHARPYUV_EXTERN WEBP_EXTERN
|
|
#else
|
|
// This explicitly marks library functions and allows for changing the
|
|
// signature for e.g., Windows DLL builds.
|
|
#if defined(__GNUC__) && __GNUC__ >= 4
|
|
#define SHARPYUV_EXTERN extern __attribute__((visibility("default")))
|
|
#else
|
|
#if defined(_MSC_VER) && defined(WEBP_DLL)
|
|
#define SHARPYUV_EXTERN __declspec(dllexport)
|
|
#else
|
|
#define SHARPYUV_EXTERN extern
|
|
#endif /* _MSC_VER && WEBP_DLL */
|
|
#endif /* __GNUC__ >= 4 */
|
|
#endif /* WEBP_EXTERN */
|
|
#endif /* SHARPYUV_EXTERN */
|
|
|
|
// SharpYUV API version following the convention from semver.org
|
|
#define SHARPYUV_VERSION_MAJOR 0
|
|
#define SHARPYUV_VERSION_MINOR 2
|
|
#define SHARPYUV_VERSION_PATCH 1
|
|
// Version as a uint32_t. The major number is the high 8 bits.
|
|
// The minor number is the middle 8 bits. The patch number is the low 16 bits.
|
|
#define SHARPYUV_MAKE_VERSION(MAJOR, MINOR, PATCH) \
|
|
(((MAJOR) << 24) | ((MINOR) << 16) | (PATCH))
|
|
#define SHARPYUV_VERSION \
|
|
SHARPYUV_MAKE_VERSION(SHARPYUV_VERSION_MAJOR, SHARPYUV_VERSION_MINOR, \
|
|
SHARPYUV_VERSION_PATCH)
|
|
|
|
// Returns the library's version number, packed in hexadecimal. See
|
|
// SHARPYUV_VERSION.
|
|
SHARPYUV_EXTERN int SharpYuvGetVersion(void);
|
|
|
|
// 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;
|
|
|
|
// 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).
|
|
// Assumes that the image will be upsampled using a bilinear filter. If nearest
|
|
// neighbor is used instead, the upsampled image might look worse than with
|
|
// standard downsampling.
|
|
// r_ptr, g_ptr, b_ptr: pointers to the source r, g and b channels. Should point
|
|
// to uint8_t buffers if rgb_bit_depth is 8, or uint16_t buffers otherwise.
|
|
// rgb_step: distance in bytes between two horizontally adjacent pixels on the
|
|
// r, g and b channels. If rgb_bit_depth is > 8, it should be a
|
|
// multiple of 2.
|
|
// rgb_stride: distance in bytes between two vertically adjacent pixels on the
|
|
// r, g, and b channels. If rgb_bit_depth is > 8, it should be a
|
|
// multiple of 2.
|
|
// rgb_bit_depth: number of bits for each r/g/b value. One of: 8, 10, 12, 16.
|
|
// Note: 16 bit input is truncated to 14 bits before conversion to yuv.
|
|
// yuv_bit_depth: number of bits for each y/u/v value. One of: 8, 10, 12.
|
|
// y_ptr, u_ptr, v_ptr: pointers to the destination y, u and v channels. Should
|
|
// point to uint8_t buffers if yuv_bit_depth is 8, or uint16_t buffers
|
|
// otherwise.
|
|
// y_stride, u_stride, v_stride: distance in bytes between two vertically
|
|
// adjacent pixels on the y, u and v channels. If yuv_bit_depth > 8, they
|
|
// should be multiples of 2.
|
|
// width, height: width and height of the image in pixels
|
|
SHARPYUV_EXTERN int SharpYuvConvert(const void* r_ptr, const void* g_ptr,
|
|
const void* b_ptr, int rgb_step,
|
|
int rgb_stride, int rgb_bit_depth,
|
|
void* y_ptr, int y_stride, void* u_ptr,
|
|
int u_stride, void* v_ptr, int v_stride,
|
|
int yuv_bit_depth, int width, int height,
|
|
const SharpYuvConversionMatrix* yuv_matrix);
|
|
|
|
// TODO(b/194336375): Add YUV444 to YUV420 conversion. Maybe also add 422
|
|
// support (it's rarely used in practice, especially for images).
|
|
|
|
#ifdef __cplusplus
|
|
} // extern "C"
|
|
#endif
|
|
|
|
#endif // WEBP_SHARPYUV_SHARPYUV_H_
|