mirror of
https://github.com/webmproject/libwebp.git
synced 2025-07-13 06:24:27 +02:00
a WebP encoder
converts PNG & JPEG to WebP This is an experimental early version, with lot of room of later optimizations in both speed and quality. Compile with the usual `./configure && make` Command line example is examples/cwebp Usage: cwebp [options] -q quality input.png -o output.webp where 'quality' is between 0 (poor) to 100 (very good). Typical value is around 80. More encoding options with 'cwebp -longhelp' Change-Id: I577a94f6f622a0c44bdfa9daf1086ace89d45539
This commit is contained in:
Pascal Massimino
216
src/webp/encode.h
Normal file
216
src/webp/encode.h
Normal file
@ -0,0 +1,216 @@
|
||||
// Copyright 2011 Google Inc.
|
||||
//
|
||||
// This code is licensed under the same terms as WebM:
|
||||
// Software License Agreement: http://www.webmproject.org/license/software/
|
||||
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
|
||||
// -----------------------------------------------------------------------------
|
||||
//
|
||||
// WebP encoder: main interface
|
||||
//
|
||||
// Author: Skal (pascal.massimino@gmail.com)
|
||||
|
||||
#ifndef WEBP_WEBP_ENCODE_H_
|
||||
#define WEBP_WEBP_ENCODE_H_
|
||||
|
||||
#include <stdlib.h>
|
||||
|
||||
#include "webp/types.h"
|
||||
|
||||
#if defined(__cplusplus) || defined(c_plusplus)
|
||||
extern "C" {
|
||||
#endif
|
||||
|
||||
#define WEBP_ENCODER_ABI_VERSION 0x0001
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
// One-stop-shop call! No questions asked:
|
||||
|
||||
// Returns the size of the compressed data (pointed to by *output), or 0 if
|
||||
// an error occurred. The compressed data must be released by the caller
|
||||
// using the call 'free(*output)'.
|
||||
// Currently, alpha values are discarded.
|
||||
size_t WebPEncodeRGB(const uint8_t* rgb, int width, int height, int stride,
|
||||
float quality_factor, uint8_t** output);
|
||||
size_t WebPEncodeBGR(const uint8_t* bgr, int width, int height, int stride,
|
||||
float quality_factor, uint8_t** output);
|
||||
size_t WebPEncodeRGBA(const uint8_t* rgba, int width, int height, int stride,
|
||||
float quality_factor, uint8_t** output);
|
||||
size_t WebPEncodeBGRA(const uint8_t* bgra, int width, int height, int stride,
|
||||
float quality_factor, uint8_t** output);
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
// Coding parameters
|
||||
|
||||
typedef struct {
|
||||
float quality; // between 0 (smallest file) and 100 (biggest)
|
||||
int target_size; // if non-zero, set the desired target size in bytes.
|
||||
// Takes precedence over the 'compression' parameter.
|
||||
float target_PSNR; // if non-zero, specifies the minimal distortion to
|
||||
// try to achieve. Takes precedence over target_size.
|
||||
int method; // quality/speed trade-off (0=fast, 6=slower-better)
|
||||
int segments; // maximum number of segments to use, in [1..4]
|
||||
int sns_strength; // Spatial Noise Shaping. 0=off, 100=maximum.
|
||||
int filter_strength; // range: [0 = off .. 100 = strongest]
|
||||
int filter_sharpness; // range: [0 = off .. 7 = least sharp]
|
||||
int filter_type; // filtering type: 0 = simple, 1 = strong
|
||||
// (only used if filter_strength > 0 or autofilter > 0)
|
||||
int autofilter; // Auto adjust filter's strength [0 = off, 1 = on]
|
||||
int pass; // number of entropy-analysis passes (in [1..10]).
|
||||
|
||||
int show_compressed; // if true, export the compressed picture back.
|
||||
// In-loop filtering is not applied.
|
||||
int preprocessing; // preprocessing filter (0=none, 1=segment-smooth)
|
||||
int partitions; // log2(number of token partitions) in [0..3]
|
||||
// Default is set to 0 for easier progressive decoding.
|
||||
} WebPConfig;
|
||||
|
||||
// Enumerate some predefined settings for WebPConfig, depending on the type
|
||||
// of source picture. These presets are used when calling WebPConfigPreset().
|
||||
typedef enum {
|
||||
WEBP_PRESET_DEFAULT = 0, // default preset.
|
||||
WEBP_PRESET_PICTURE, // digital picture, like portrait, inner shot
|
||||
WEBP_PRESET_PHOTO, // outdoor photograph, with natural lighting
|
||||
WEBP_PRESET_DRAWING, // hand or line drawing, with high-contrast details
|
||||
WEBP_PRESET_ICON, // small-sized colorful images
|
||||
WEBP_PRESET_TEXT // text-like
|
||||
} WebPPreset;
|
||||
|
||||
// Internal, version-checked, entry point
|
||||
int WebPConfigInitInternal(WebPConfig* const, WebPPreset, float, int);
|
||||
|
||||
// Should always be called, to initialize a fresh WebPConfig structure before
|
||||
// modification. Returns 0 in case of version mismatch. WebPConfigInit() must
|
||||
// have succeeded before using the 'config' object.
|
||||
static inline int WebPConfigInit(WebPConfig* const config) {
|
||||
return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f,
|
||||
WEBP_ENCODER_ABI_VERSION);
|
||||
}
|
||||
|
||||
// This function will initialize the configuration according to a predefined
|
||||
// set of parameters (referred to by 'preset') and a given quality factor.
|
||||
// This function can be called as a replacement to WebPConfigInit(). Will
|
||||
// return 0 in case of error.
|
||||
static inline int WebPConfigPreset(WebPConfig* const config,
|
||||
WebPPreset preset, float quality) {
|
||||
return WebPConfigInitInternal(config, preset, quality,
|
||||
WEBP_ENCODER_ABI_VERSION);
|
||||
}
|
||||
|
||||
// Returns 1 if all parameters are in valid range and the configuration is OK.
|
||||
int WebPValidateConfig(const WebPConfig* const config);
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
// Input / Output
|
||||
|
||||
typedef struct WebPPicture WebPPicture; // main structure for I/O
|
||||
|
||||
// non-essential structure for storing auxilliary statistics
|
||||
typedef struct {
|
||||
float PSNR[4]; // peak-signal-to-noise ratio for Y/U/V/All
|
||||
int coded_size; // final size
|
||||
int block_count[3]; // number of intra4/intra16/skipped macroblocks
|
||||
int header_bytes[2]; // approximative number of bytes spent for header
|
||||
// and mode-partition #0
|
||||
int residual_bytes[3][4]; // approximative number of bytes spent for
|
||||
// DC/AC/uv coefficients for each (0..3) segments.
|
||||
int segment_size[4]; // number of macroblocks in each segments
|
||||
int segment_quant[4]; // quantizer values for each segments
|
||||
int segment_level[4]; // filtering strength for each segments [0..63]
|
||||
} WebPAuxStats;
|
||||
|
||||
// Signature for output function. Should return 1 if writing was successful.
|
||||
// data/data_size is the segment of data to write, and 'picture' is for
|
||||
// reference (and so one can make use of picture->custom_ptr).
|
||||
typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size,
|
||||
const WebPPicture* const picture);
|
||||
|
||||
struct WebPPicture {
|
||||
// input
|
||||
int colorspace; // colorspace: should be 0 for now (=Y'CbCr).
|
||||
int width, height; // dimensions.
|
||||
uint8_t *y, *u, *v; // pointers to luma/chroma planes.
|
||||
int y_stride, uv_stride; // luma/chroma strides.
|
||||
uint8_t *a; // pointer to the alpha plane (unused for now).
|
||||
|
||||
// output
|
||||
WebPWriterFunction writer; // can be NULL
|
||||
void* custom_ptr; // can be used by the writer.
|
||||
|
||||
// map for extra information
|
||||
int extra_info_type; // 1: intra type, 2: segment, 3: quant
|
||||
// 4: intra-16 prediction mode,
|
||||
// 5: chroma prediction mode,
|
||||
// 6: bit cost, 7: distortion
|
||||
uint8_t* extra_info; // if not NULL, points to an array of size
|
||||
// ((width + 15) / 16) * ((height + 15) / 16) that
|
||||
// will be filled with a macroblock map, depending
|
||||
// on extra_info_type.
|
||||
|
||||
// where to store statistics, if not NULL:
|
||||
WebPAuxStats* stats;
|
||||
};
|
||||
|
||||
// Internal, version-checked, entry point
|
||||
int WebPPictureInitInternal(WebPPicture* const, int);
|
||||
|
||||
// Should always be called, to initialize the structure. Returns 0 in case of
|
||||
// version mismatch. WebPPictureInit() must have succeeded before using the
|
||||
// 'picture' object.
|
||||
static inline int WebPPictureInit(WebPPicture* const picture) {
|
||||
return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION);
|
||||
}
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
// WebPPicture utils
|
||||
|
||||
// Convenience allocation / deallocation based on picture->width/height:
|
||||
// Allocate y/u/v buffers as per width/height specification.
|
||||
// Note! This function will free the previous buffer if needed.
|
||||
// Returns 0 in case of memory error.
|
||||
int WebPPictureAlloc(WebPPicture* const picture);
|
||||
|
||||
// Release memory allocated by WebPPictureAlloc() or WebPPictureImport*()
|
||||
// Note that this function does _not_ free the memory pointed to by 'picture'.
|
||||
void WebPPictureFree(WebPPicture* const picture);
|
||||
|
||||
// Copy the pixels of *src into *dst, using WebPPictureAlloc.
|
||||
// Returns 0 in case of memory allocation error.
|
||||
int WebPPictureCopy(const WebPPicture* const src, WebPPicture* const dst);
|
||||
|
||||
// self-crops a picture to the rectangle defined by top/left/width/height.
|
||||
// Returns 0 in case of memory allocation error, or if the rectangle is
|
||||
// outside of the source picture.
|
||||
int WebPPictureCrop(WebPPicture* const picture,
|
||||
int left, int top, int width, int height);
|
||||
|
||||
// Colorspace conversion function. Previous buffer will be free'd, if any.
|
||||
// *rgb buffer should have a size of at least height * rgb_stride.
|
||||
// Returns 0 in case of memory error.
|
||||
int WebPPictureImportRGB(WebPPicture* const picture,
|
||||
const uint8_t* const rgb, int rgb_stride);
|
||||
// Same, but for RGBA buffer. Alpha information is ignored.
|
||||
int WebPPictureImportRGBA(WebPPicture* const picture,
|
||||
const uint8_t* const rgba, int rgba_stride);
|
||||
|
||||
// Variant of the above, but taking BGR input:
|
||||
int WebPPictureImportBGR(WebPPicture* const picture,
|
||||
const uint8_t* const bgr, int bgr_stride);
|
||||
int WebPPictureImportBGRA(WebPPicture* const picture,
|
||||
const uint8_t* const bgra, int bgra_stride);
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
// Main call
|
||||
|
||||
// Main encoding call, after config and picture have been initialiazed.
|
||||
// 'picture' must be less than 16384x16384 in dimension, and the 'config' object
|
||||
// must be a valid one.
|
||||
// Returns false in case of error, true otherwise.
|
||||
int WebPEncode(const WebPConfig* const config, WebPPicture* const picture);
|
||||
|
||||
//-----------------------------------------------------------------------------
|
||||
|
||||
#if defined(__cplusplus) || defined(c_plusplus)
|
||||
} // extern "C"
|
||||
#endif
|
||||
|
||||
#endif /* WEBP_WEBP_ENCODE_H_ */
|
||||
Reference in New Issue
Block a user