common/cabac.h

   1 /*****************************************************************************
   2  * cabac.h: h264 encoder library
   3  *****************************************************************************
   4  * Copyright (C) 2003-2008 x264 project
   5  *
   6  * Authors: Loren Merritt <lorenm@u.washington.edu>
   7  *          Laurent Aimar <fenrir@via.ecp.fr>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 #ifndef X264_CABAC_H
  25 #define X264_CABAC_H
  26
  27 typedef struct
  28 {
  29     /* state */
  30     int i_low;
  31     int i_range;
  32
  33     /* bit stream */
  34     int i_queue;
  35     int i_bytes_outstanding;
  36
  37     uint8_t *p_start;
  38     uint8_t *p;
  39     uint8_t *p_end;
  40
  41     /* aligned for memcpy_aligned starting here */
  42     DECLARE_ALIGNED_16( int f8_bits_encoded ); // only if using x264_cabac_size_decision()
  43
  44     /* context */
  45     uint8_t state[460];
  46 } x264_cabac_t;
  47
  48 extern const uint8_t x264_cabac_transition[128][2];
  49 extern const uint16_t x264_cabac_entropy[128][2];
  50
  51 /* init the contexts given i_slice_type, the quantif and the model */
  52 void x264_cabac_context_init( x264_cabac_t *cb, int i_slice_type, int i_qp, int i_model );
  53
  54 /* encoder only: */
  55 void x264_cabac_encode_init ( x264_cabac_t *cb, uint8_t *p_data, uint8_t *p_end );
  56 void x264_cabac_encode_decision_c( x264_cabac_t *cb, int i_ctx, int b );
  57 void x264_cabac_encode_decision_asm( x264_cabac_t *cb, int i_ctx, int b );
  58 void x264_cabac_encode_bypass( x264_cabac_t *cb, int b );
  59 void x264_cabac_encode_ue_bypass( x264_cabac_t *cb, int exp_bits, int val );
  60 void x264_cabac_encode_terminal( x264_cabac_t *cb );
  61 void x264_cabac_encode_flush( x264_t *h, x264_cabac_t *cb );
  62
  63 #ifdef HAVE_MMX
  64 #define x264_cabac_encode_decision x264_cabac_encode_decision_asm
  65 #else
  66 #define x264_cabac_encode_decision x264_cabac_encode_decision_c
  67 #endif
  68 #define x264_cabac_encode_decision_noup x264_cabac_encode_decision
  69
  70 static inline int x264_cabac_pos( x264_cabac_t *cb )
  71 {
  72     return (cb->p - cb->p_start + cb->i_bytes_outstanding) * 8 + cb->i_queue;
  73 }
  74
  75 /* internal only. these don't write the bitstream, just calculate bit cost: */
  76
  77 static inline void x264_cabac_size_decision( x264_cabac_t *cb, long i_ctx, long b )
  78 {
  79     int i_state = cb->state[i_ctx];
  80     cb->state[i_ctx] = x264_cabac_transition[i_state][b];
  81     cb->f8_bits_encoded += x264_cabac_entropy[i_state][b];
  82 }
  83
  84 static inline int x264_cabac_size_decision2( uint8_t *state, long b )
  85 {
  86     int i_state = *state;
  87     *state = x264_cabac_transition[i_state][b];
  88     return x264_cabac_entropy[i_state][b];
  89 }
  90
  91 static inline void x264_cabac_size_decision_noup( x264_cabac_t *cb, long i_ctx, long b )
  92 {
  93     int i_state = cb->state[i_ctx];
  94     cb->f8_bits_encoded += x264_cabac_entropy[i_state][b];
  95 }
  96
  97 static inline int x264_cabac_size_decision_noup2( uint8_t *state, long b )
  98 {
  99     return x264_cabac_entropy[*state][b];
 100 }
 101
 102 #endif