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 * Module Title : boolhuff.h 14 * 15 * Description : Bool Coder header file. 16 * 17 ****************************************************************************/ 18 #ifndef VP8_ENCODER_BOOLHUFF_H_ 19 #define VP8_ENCODER_BOOLHUFF_H_ 20 21 #include "vpx_ports/mem.h" 22 #include "vpx/internal/vpx_codec_internal.h" 23 24 #ifdef __cplusplus 25 extern "C" { 26 #endif 27 28 typedef struct { 29 unsigned int lowvalue; 30 unsigned int range; 31 int count; 32 unsigned int pos; 33 unsigned char *buffer; 34 unsigned char *buffer_end; 35 struct vpx_internal_error_info *error; 36 } BOOL_CODER; 37 38 extern void vp8_start_encode(BOOL_CODER *bc, unsigned char *buffer, 39 unsigned char *buffer_end); 40 41 extern void vp8_encode_value(BOOL_CODER *br, int data, int bits); 42 extern void vp8_stop_encode(BOOL_CODER *bc); 43 extern const unsigned int vp8_prob_cost[256]; 44 45 DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]); 46 47 static int validate_buffer(const unsigned char *start, size_t len, 48 const unsigned char *end, 49 struct vpx_internal_error_info *error) { 50 if (start + len > start && start + len < end) { 51 return 1; 52 } else { 53 vpx_internal_error(error, VPX_CODEC_CORRUPT_FRAME, 54 "Truncated packet or corrupt partition "); 55 } 56 57 return 0; 58 } 59 static void vp8_encode_bool(BOOL_CODER *br, int bit, int probability) { 60 unsigned int split; 61 int count = br->count; 62 unsigned int range = br->range; 63 unsigned int lowvalue = br->lowvalue; 64 register int shift; 65 66 #ifdef VP8_ENTROPY_STATS 67 #if defined(SECTIONBITS_OUTPUT) 68 69 if (bit) 70 Sectionbits[active_section] += vp8_prob_cost[255 - probability]; 71 else 72 Sectionbits[active_section] += vp8_prob_cost[probability]; 73 74 #endif 75 #endif 76 77 split = 1 + (((range - 1) * probability) >> 8); 78 79 range = split; 80 81 if (bit) { 82 lowvalue += split; 83 range = br->range - split; 84 } 85 86 shift = vp8_norm[range]; 87 88 range <<= shift; 89 count += shift; 90 91 if (count >= 0) { 92 int offset = shift - count; 93 94 if ((lowvalue << (offset - 1)) & 0x80000000) { 95 int x = br->pos - 1; 96 97 while (x >= 0 && br->buffer[x] == 0xff) { 98 br->buffer[x] = (unsigned char)0; 99 x--; 100 } 101 102 br->buffer[x] += 1; 103 } 104 105 validate_buffer(br->buffer + br->pos, 1, br->buffer_end, br->error); 106 br->buffer[br->pos++] = (lowvalue >> (24 - offset)); 107 108 lowvalue <<= offset; 109 shift = count; 110 lowvalue &= 0xffffff; 111 count -= 8; 112 } 113 114 lowvalue <<= shift; 115 br->count = count; 116 br->lowvalue = lowvalue; 117 br->range = range; 118 } 119 120 #ifdef __cplusplus 121 } // extern "C" 122 #endif 123 124 #endif // VP8_ENCODER_BOOLHUFF_H_ 125
