1 /* 2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 12 /**************************************************************************** 13 * 14 * Module Title : boolhuff.h 15 * 16 * Description : Bool Coder header file. 17 * 18 ****************************************************************************/ 19 #ifndef __INC_BOOLHUFF_H 20 #define __INC_BOOLHUFF_H 21 22 #include "vpx_ports/mem.h" 23 #include "vpx/internal/vpx_codec_internal.h" 24 25 typedef struct 26 { 27 unsigned int lowvalue; 28 unsigned int range; 29 int count; 30 unsigned int pos; 31 unsigned char *buffer; 32 unsigned char *buffer_end; 33 struct vpx_internal_error_info *error; 34 35 /* Variables used to track bit costs without outputing to the bitstream */ 36 unsigned int measure_cost; 37 unsigned long bit_counter; 38 } BOOL_CODER; 39 40 extern void vp8_start_encode(BOOL_CODER *bc, unsigned char *buffer, unsigned char *buffer_end); 41 42 extern void vp8_encode_value(BOOL_CODER *br, int data, int bits); 43 extern void vp8_stop_encode(BOOL_CODER *bc); 44 extern const unsigned int vp8_prob_cost[256]; 45 46 47 DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]); 48 49 static int validate_buffer(const unsigned char *start, 50 size_t len, 51 const unsigned char *end, 52 struct vpx_internal_error_info *error) 53 { 54 if (start + len > start && start + len < end) 55 return 1; 56 else 57 vpx_internal_error(error, VPX_CODEC_CORRUPT_FRAME, 58 "Truncated packet or corrupt partition "); 59 60 return 0; 61 } 62 static void vp8_encode_bool(BOOL_CODER *br, int bit, int probability) 63 { 64 unsigned int split; 65 int count = br->count; 66 unsigned int range = br->range; 67 unsigned int lowvalue = br->lowvalue; 68 register unsigned int shift; 69 70 #ifdef VP8_ENTROPY_STATS 71 #if defined(SECTIONBITS_OUTPUT) 72 73 if (bit) 74 Sectionbits[active_section] += vp8_prob_cost[255-probability]; 75 else 76 Sectionbits[active_section] += vp8_prob_cost[probability]; 77 78 #endif 79 #endif 80 81 split = 1 + (((range - 1) * probability) >> 8); 82 83 range = split; 84 85 if (bit) 86 { 87 lowvalue += split; 88 range = br->range - split; 89 } 90 91 shift = vp8_norm[range]; 92 93 range <<= shift; 94 count += shift; 95 96 if (count >= 0) 97 { 98 int offset = shift - count; 99 100 if ((lowvalue << (offset - 1)) & 0x80000000) 101 { 102 int x = br->pos - 1; 103 104 while (x >= 0 && br->buffer[x] == 0xff) 105 { 106 br->buffer[x] = (unsigned char)0; 107 x--; 108 } 109 110 br->buffer[x] += 1; 111 } 112 113 validate_buffer(br->buffer + br->pos, 1, br->buffer_end, br->error); 114 br->buffer[br->pos++] = (lowvalue >> (24 - offset)); 115 116 lowvalue <<= offset; 117 shift = count; 118 lowvalue &= 0xffffff; 119 count -= 8 ; 120 } 121 122 lowvalue <<= shift; 123 br->count = count; 124 br->lowvalue = lowvalue; 125 br->range = range; 126 } 127 128 #endif 129
