Libav
ffv1.h
Go to the documentation of this file.
1 /*
2  * FFV1 codec for libavcodec
3  *
4  * Copyright (c) 2003-2012 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of Libav.
7  *
8  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #ifndef AVCODEC_FFV1_H
24 #define AVCODEC_FFV1_H
25 
26 #include <stdint.h>
27 
28 #include "avcodec.h"
29 #include "dsputil.h"
30 #include "get_bits.h"
31 #include "put_bits.h"
32 #include "rangecoder.h"
33 
34 #define MAX_PLANES 4
35 #define CONTEXT_SIZE 32
36 
37 #define MAX_QUANT_TABLES 8
38 #define MAX_CONTEXT_INPUTS 5
39 
40 extern const uint8_t ff_log2_run[41];
41 
42 extern const int8_t ffv1_quant5_10bit[256];
43 extern const int8_t ffv1_quant5[256];
44 extern const int8_t ffv1_quant9_10bit[256];
45 extern const int8_t ffv1_quant11[256];
46 extern const uint8_t ffv1_ver2_state[256];
47 
48 typedef struct VlcState {
49  int16_t drift;
50  uint16_t error_sum;
51  int8_t bias;
53 } VlcState;
54 
55 typedef struct PlaneContext {
62 } PlaneContext;
63 
64 #define MAX_SLICES 256
65 
66 typedef struct FFV1Context {
67  AVClass *class;
72  uint64_t rc_stat[256][2];
73  uint64_t (*rc_stat2[MAX_QUANT_TABLES])[32][2];
74  int version;
76  int width, height;
80  int flags;
84 
87  int ac; // 1 = range coder <-> 0 = golomb rice
88  int ac_byte_count; // number of bytes used for AC coding
95  int run_index;
97  int16_t *sample_buffer;
98 
99  int ec;
102 
105 
108 
110 
117  int slice_x;
118  int slice_y;
119 } FFV1Context;
120 
121 static av_always_inline int fold(int diff, int bits)
122 {
123  if (bits == 8)
124  diff = (int8_t)diff;
125  else {
126  diff += 1 << (bits - 1);
127  diff &= (1 << bits) - 1;
128  diff -= 1 << (bits - 1);
129  }
130 
131  return diff;
132 }
133 
134 static inline int predict(int16_t *src, int16_t *last)
135 {
136  const int LT = last[-1];
137  const int T = last[0];
138  const int L = src[-1];
139 
140  return mid_pred(L, L + T - LT, T);
141 }
142 
143 static inline int get_context(PlaneContext *p, int16_t *src,
144  int16_t *last, int16_t *last2)
145 {
146  const int LT = last[-1];
147  const int T = last[0];
148  const int RT = last[1];
149  const int L = src[-1];
150 
151  if (p->quant_table[3][127]) {
152  const int TT = last2[0];
153  const int LL = src[-2];
154  return p->quant_table[0][(L - LT) & 0xFF] +
155  p->quant_table[1][(LT - T) & 0xFF] +
156  p->quant_table[2][(T - RT) & 0xFF] +
157  p->quant_table[3][(LL - L) & 0xFF] +
158  p->quant_table[4][(TT - T) & 0xFF];
159  } else
160  return p->quant_table[0][(L - LT) & 0xFF] +
161  p->quant_table[1][(LT - T) & 0xFF] +
162  p->quant_table[2][(T - RT) & 0xFF];
163 }
164 
165 static inline void update_vlc_state(VlcState *const state, const int v)
166 {
167  int drift = state->drift;
168  int count = state->count;
169  state->error_sum += FFABS(v);
170  drift += v;
171 
172  if (count == 128) { // FIXME: variable
173  count >>= 1;
174  drift >>= 1;
175  state->error_sum >>= 1;
176  }
177  count++;
178 
179  if (drift <= -count) {
180  if (state->bias > -128)
181  state->bias--;
182 
183  drift += count;
184  if (drift <= -count)
185  drift = -count + 1;
186  } else if (drift > 0) {
187  if (state->bias < 127)
188  state->bias++;
189 
190  drift -= count;
191  if (drift > 0)
192  drift = 0;
193  }
194 
195  state->drift = drift;
196  state->count = count;
197 }
198 
205 
206 #endif /* AVCODEC_FFV1_H */