Home | History | Annotate | Download | only in enc 
      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 (at) 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_[3];  // 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