1 // Copyright 2012 Google Inc. All Rights Reserved.
2 //
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the COPYING file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8 // -----------------------------------------------------------------------------
9 //
10 // Lossless encoder: internal header.
11 //
12 // Author: Vikas Arora (vikaas.arora@gmail.com)
13 
14 #ifndef WEBP_ENC_VP8LI_ENC_H_
15 #define WEBP_ENC_VP8LI_ENC_H_
16 
17 #ifdef HAVE_CONFIG_H
18 #include "src/webp/config.h"
19 #endif
20 // Either WEBP_NEAR_LOSSLESS is defined as 0 in config.h when compiling to
21 // disable near-lossless, or it is enabled by default.
22 #ifndef WEBP_NEAR_LOSSLESS
23 #define WEBP_NEAR_LOSSLESS 1
24 #endif
25 
26 #include "src/enc/backward_references_enc.h"
27 #include "src/enc/histogram_enc.h"
28 #include "src/utils/bit_writer_utils.h"
29 #include "src/webp/encode.h"
30 #include "src/webp/format_constants.h"
31 
32 #ifdef __cplusplus
33 extern "C" {
34 #endif
35 
36 // maximum value of transform_bits_ in VP8LEncoder.
37 #define MAX_TRANSFORM_BITS 6
38 
39 typedef enum {
40   kEncoderNone = 0,
41   kEncoderARGB,
42   kEncoderNearLossless,
43   kEncoderPalette
44 } VP8LEncoderARGBContent;
45 
46 typedef struct {
47   const WebPConfig* config_;      // user configuration and parameters
48   const WebPPicture* pic_;        // input picture.
49 
50   uint32_t* argb_;                       // Transformed argb image data.
51   VP8LEncoderARGBContent argb_content_;  // Content type of the argb buffer.
52   uint32_t* argb_scratch_;               // Scratch memory for argb rows
53                                          // (used for prediction).
54   uint32_t* transform_data_;             // Scratch memory for transform data.
55   uint32_t* transform_mem_;              // Currently allocated memory.
56   size_t    transform_mem_size_;         // Currently allocated memory size.
57 
58   int       current_width_;       // Corresponds to packed image width.
59 
60   // Encoding parameters derived from quality parameter.
61   int histo_bits_;
62   int transform_bits_;    // <= MAX_TRANSFORM_BITS.
63   int cache_bits_;        // If equal to 0, don't use color cache.
64 
65   // Encoding parameters derived from image characteristics.
66   int use_cross_color_;
67   int use_subtract_green_;
68   int use_predict_;
69   int use_palette_;
70   int palette_size_;
71   uint32_t palette_[MAX_PALETTE_SIZE];
72 
73   // Some 'scratch' (potentially large) objects.
74   struct VP8LBackwardRefs refs_[4];  // Backward Refs array for temporaries.
75   VP8LHashChain hash_chain_;         // HashChain data for constructing
76                                      // backward references.
77 } VP8LEncoder;
78 
79 //------------------------------------------------------------------------------
80 // internal functions. Not public.
81 
82 // Encodes the picture.
83 // Returns 0 if config or picture is NULL or picture doesn't have valid argb
84 // input.
85 int VP8LEncodeImage(const WebPConfig* const config,
86                     const WebPPicture* const picture);
87 
88 // Encodes the main image stream using the supplied bit writer.
89 // If 'use_cache' is false, disables the use of color cache.
90 WebPEncodingError VP8LEncodeStream(const WebPConfig* const config,
91                                    const WebPPicture* const picture,
92                                    VP8LBitWriter* const bw, int use_cache);
93 
94 #if (WEBP_NEAR_LOSSLESS == 1)
95 // in near_lossless.c
96 // Near lossless preprocessing in RGB color-space.
97 int VP8ApplyNearLossless(const WebPPicture* const picture, int quality,
98                          uint32_t* const argb_dst);
99 #endif
100 
101 //------------------------------------------------------------------------------
102 // Image transforms in predictor.c.
103 
104 void VP8LResidualImage(int width, int height, int bits, int low_effort,
105                        uint32_t* const argb, uint32_t* const argb_scratch,
106                        uint32_t* const image, int near_lossless, int exact,
107                        int used_subtract_green);
108 
109 void VP8LColorSpaceTransform(int width, int height, int bits, int quality,
110                              uint32_t* const argb, uint32_t* image);
111 
112 //------------------------------------------------------------------------------
113 
114 #ifdef __cplusplus
115 }    // extern "C"
116 #endif
117 
118 #endif  // WEBP_ENC_VP8LI_ENC_H_
119