michael@0: /*
michael@0:  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0:  *
michael@0:  *  Use of this source code is governed by a BSD-style license
michael@0:  *  that can be found in the LICENSE file in the root of the source
michael@0:  *  tree. An additional intellectual property rights grant can be found
michael@0:  *  in the file PATENTS.  All contributing project authors may
michael@0:  *  be found in the AUTHORS file in the root of the source tree.
michael@0:  */
michael@0: 
michael@0: 
michael@0: /****************************************************************************
michael@0: *
michael@0: *   Module Title :     vp9_boolhuff.h
michael@0: *
michael@0: *   Description  :     Bool Coder header file.
michael@0: *
michael@0: ****************************************************************************/
michael@0: #ifndef VP9_ENCODER_VP9_BOOLHUFF_H_
michael@0: #define VP9_ENCODER_VP9_BOOLHUFF_H_
michael@0: 
michael@0: #include "vpx_ports/mem.h"
michael@0: 
michael@0: typedef struct {
michael@0:   unsigned int lowvalue;
michael@0:   unsigned int range;
michael@0:   unsigned int value;
michael@0:   int count;
michael@0:   unsigned int pos;
michael@0:   uint8_t *buffer;
michael@0: 
michael@0:   // Variables used to track bit costs without outputing to the bitstream
michael@0:   unsigned int  measure_cost;
michael@0:   unsigned long bit_counter;
michael@0: } vp9_writer;
michael@0: 
michael@0: extern const unsigned int vp9_prob_cost[256];
michael@0: 
michael@0: void vp9_start_encode(vp9_writer *bc, uint8_t *buffer);
michael@0: void vp9_stop_encode(vp9_writer *bc);
michael@0: 
michael@0: DECLARE_ALIGNED(16, extern const unsigned char, vp9_norm[256]);
michael@0: 
michael@0: static void vp9_write(vp9_writer *br, int bit, int probability) {
michael@0:   unsigned int split;
michael@0:   int count = br->count;
michael@0:   unsigned int range = br->range;
michael@0:   unsigned int lowvalue = br->lowvalue;
michael@0:   register unsigned int shift;
michael@0: 
michael@0: #ifdef ENTROPY_STATS
michael@0: #if defined(SECTIONBITS_OUTPUT)
michael@0: 
michael@0:   if (bit)
michael@0:     Sectionbits[active_section] += vp9_prob_cost[255 - probability];
michael@0:   else
michael@0:     Sectionbits[active_section] += vp9_prob_cost[probability];
michael@0: 
michael@0: #endif
michael@0: #endif
michael@0: 
michael@0:   split = 1 + (((range - 1) * probability) >> 8);
michael@0: 
michael@0:   range = split;
michael@0: 
michael@0:   if (bit) {
michael@0:     lowvalue += split;
michael@0:     range = br->range - split;
michael@0:   }
michael@0: 
michael@0:   shift = vp9_norm[range];
michael@0: 
michael@0:   range <<= shift;
michael@0:   count += shift;
michael@0: 
michael@0:   if (count >= 0) {
michael@0:     int offset = shift - count;
michael@0: 
michael@0:     if ((lowvalue << (offset - 1)) & 0x80000000) {
michael@0:       int x = br->pos - 1;
michael@0: 
michael@0:       while (x >= 0 && br->buffer[x] == 0xff) {
michael@0:         br->buffer[x] = 0;
michael@0:         x--;
michael@0:       }
michael@0: 
michael@0:       br->buffer[x] += 1;
michael@0:     }
michael@0: 
michael@0:     br->buffer[br->pos++] = (lowvalue >> (24 - offset));
michael@0:     lowvalue <<= offset;
michael@0:     shift = count;
michael@0:     lowvalue &= 0xffffff;
michael@0:     count -= 8;
michael@0:   }
michael@0: 
michael@0:   lowvalue <<= shift;
michael@0:   br->count = count;
michael@0:   br->lowvalue = lowvalue;
michael@0:   br->range = range;
michael@0: }
michael@0: 
michael@0: static void vp9_write_bit(vp9_writer *w, int bit) {
michael@0:   vp9_write(w, bit, 128);  // vp9_prob_half
michael@0: }
michael@0: 
michael@0: static void vp9_write_literal(vp9_writer *w, int data, int bits) {
michael@0:   int bit;
michael@0: 
michael@0:   for (bit = bits - 1; bit >= 0; bit--)
michael@0:     vp9_write_bit(w, 1 & (data >> bit));
michael@0: }
michael@0: 
michael@0: 
michael@0: #endif  // VP9_ENCODER_VP9_BOOLHUFF_H_