libavcodec/put_golomb.h

   1 /*
   2  * exp golomb vlc writing stuff
   3  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
   4  * Copyright (c) 2004 Alex Beregszaszi
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file
  25  * @brief
  26  *     exp golomb vlc writing stuff
  27  * @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
  28  */
  29
  30 #ifndef AVCODEC_PUT_GOLOMB_H
  31 #define AVCODEC_PUT_GOLOMB_H
  32
  33 #include <stdint.h>
  34 #include "put_bits.h"
  35
  36 extern const uint8_t ff_ue_golomb_len[256];
  37
  38 /**
  39  * write unsigned exp golomb code. 2^16 - 2 at most
  40  */
  41 static inline void set_ue_golomb(PutBitContext *pb, int i)
  42 {
  43     av_assert2(i >= 0);
  44     av_assert2(i <= 0xFFFE);
  45
  46     if (i < 256)
  47         put_bits(pb, ff_ue_golomb_len[i], i + 1);
  48     else {
  49         int e = av_log2(i + 1);
  50         put_bits(pb, 2 * e + 1, i + 1);
  51     }
  52 }
  53
  54 /**
  55  * write unsigned exp golomb code. 2^32-2 at most.
  56  */
  57 static inline void set_ue_golomb_long(PutBitContext *pb, uint32_t i)
  58 {
  59     av_assert2(i <= (UINT32_MAX - 1));
  60
  61     if (i < 256)
  62         put_bits(pb, ff_ue_golomb_len[i], i + 1);
  63     else {
  64         int e = av_log2(i + 1);
  65         put_bits64(pb, 2 * e + 1, i + 1);
  66     }
  67 }
  68
  69 /**
  70  * write truncated unsigned exp golomb code.
  71  */
  72 static inline void set_te_golomb(PutBitContext *pb, int i, int range)
  73 {
  74     av_assert2(range >= 1);
  75     av_assert2(i <= range);
  76
  77     if (range == 2)
  78         put_bits(pb, 1, i ^ 1);
  79     else
  80         set_ue_golomb(pb, i);
  81 }
  82
  83 /**
  84  * write signed exp golomb code. 16 bits at most.
  85  */
  86 static inline void set_se_golomb(PutBitContext *pb, int i)
  87 {
  88     i = 2 * i - 1;
  89     if (i < 0)
  90         i ^= -1;    //FIXME check if gcc does the right thing
  91     set_ue_golomb(pb, i);
  92 }
  93
  94 /**
  95  * write unsigned golomb rice code (ffv1).
  96  */
  97 static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit,
  98                                  int esc_len)
  99 {
 100     int e;
 101
 102     av_assert2(i >= 0);
 103
 104     e = i >> k;
 105     if (e < limit)
 106         put_bits(pb, e + k + 1, (1 << k) + av_zero_extend(i, k));
 107     else
 108         put_bits(pb, limit + esc_len, i - limit + 1);
 109 }
 110
 111 /**
 112  * write unsigned golomb rice code (jpegls).
 113  */
 114 static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k,
 115                                         int limit, int esc_len)
 116 {
 117     int e;
 118
 119     av_assert2(i >= 0);
 120
 121     e = (i >> k) + 1;
 122     if (e < limit) {
 123         while (e > 31) {
 124             put_bits(pb, 31, 0);
 125             e -= 31;
 126         }
 127         put_bits(pb, e, 1);
 128         if (k)
 129             put_sbits(pb, k, i);
 130     } else {
 131         while (limit > 31) {
 132             put_bits(pb, 31, 0);
 133             limit -= 31;
 134         }
 135         put_bits(pb, limit, 1);
 136         put_bits(pb, esc_len, i - 1);
 137     }
 138 }
 139
 140 /**
 141  * write signed golomb rice code (ffv1).
 142  */
 143 static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit,
 144                                  int esc_len)
 145 {
 146     int v;
 147
 148     v  = -2 * i - 1;
 149     v ^= (v >> 31);
 150
 151     set_ur_golomb(pb, v, k, limit, esc_len);
 152 }
 153
 154 #endif /* AVCODEC_PUT_GOLOMB_H */