Libav
vorbis.c
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1 /*
2  * This file is part of Libav.
3  *
4  * Libav is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
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10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with Libav; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
25 #include "libavutil/common.h"
26 
27 #include "avcodec.h"
28 #include "vorbis.h"
29 
30 
31 /* Helper functions */
32 
33 // x^(1/n)
34 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
35 {
36  unsigned int ret = 0, i, j;
37 
38  do {
39  ++ret;
40  for (i = 0, j = ret; i < n - 1; i++)
41  j *= ret;
42  } while (j <= x);
43 
44  return ret - 1;
45 }
46 
47 // Generate vlc codes from vorbis huffman code lengths
48 
49 // the two bits[p] > 32 checks should be redundant, all calling code should
50 // already ensure that, but since it allows overwriting the stack it seems
51 // reasonable to check redundantly.
52 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
53 {
54  uint32_t exit_at_level[33] = { 404 };
55  unsigned i, j, p, code;
56 
57  for (p = 0; (bits[p] == 0) && (p < num); ++p)
58  ;
59  if (p == num)
60  return 0;
61 
62  codes[p] = 0;
63  if (bits[p] > 32)
64  return 1;
65  for (i = 0; i < bits[p]; ++i)
66  exit_at_level[i+1] = 1 << i;
67 
68  ++p;
69 
70  for (; p < num; ++p) {
71  if (bits[p] > 32)
72  return 1;
73  if (bits[p] == 0)
74  continue;
75  // find corresponding exit(node which the tree can grow further from)
76  for (i = bits[p]; i > 0; --i)
77  if (exit_at_level[i])
78  break;
79  if (!i) // overspecified tree
80  return 1;
81  code = exit_at_level[i];
82  exit_at_level[i] = 0;
83  // construct code (append 0s to end) and introduce new exits
84  for (j = i + 1 ;j <= bits[p]; ++j)
85  exit_at_level[j] = code + (1 << (j - 1));
86  codes[p] = code;
87  }
88 
89  //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
90  for (p = 1; p < 33; p++)
91  if (exit_at_level[p])
92  return 1;
93 
94  return 0;
95 }
96 
98  vorbis_floor1_entry *list, int values)
99 {
100  int i;
101  list[0].sort = 0;
102  list[1].sort = 1;
103  for (i = 2; i < values; i++) {
104  int j;
105  list[i].low = 0;
106  list[i].high = 1;
107  list[i].sort = i;
108  for (j = 2; j < i; j++) {
109  int tmp = list[j].x;
110  if (tmp < list[i].x) {
111  if (tmp > list[list[i].low].x)
112  list[i].low = j;
113  } else {
114  if (tmp < list[list[i].high].x)
115  list[i].high = j;
116  }
117  }
118  }
119  for (i = 0; i < values - 1; i++) {
120  int j;
121  for (j = i + 1; j < values; j++) {
122  if (list[i].x == list[j].x) {
123  av_log(avctx, AV_LOG_ERROR,
124  "Duplicate value found in floor 1 X coordinates\n");
125  return AVERROR_INVALIDDATA;
126  }
127  if (list[list[i].sort].x > list[list[j].sort].x) {
128  int tmp = list[i].sort;
129  list[i].sort = list[j].sort;
130  list[j].sort = tmp;
131  }
132  }
133  }
134  return 0;
135 }
136 
137 static inline void render_line_unrolled(intptr_t x, int y, int x1,
138  intptr_t sy, int ady, int adx,
139  float *buf)
140 {
141  int err = -adx;
142  x -= x1 - 1;
143  buf += x1 - 1;
144  while (++x < 0) {
145  err += ady;
146  if (err >= 0) {
147  err += ady - adx;
148  y += sy;
149  buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
150  }
151  buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
152  }
153  if (x <= 0) {
154  if (err + ady >= 0)
155  y += sy;
156  buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
157  }
158 }
159 
160 static void render_line(int x0, int y0, int x1, int y1, float *buf)
161 {
162  int dy = y1 - y0;
163  int adx = x1 - x0;
164  int ady = FFABS(dy);
165  int sy = dy < 0 ? -1 : 1;
166  buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
167  if (ady*2 <= adx) { // optimized common case
168  render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
169  } else {
170  int base = dy / adx;
171  int x = x0;
172  int y = y0;
173  int err = -adx;
174  ady -= FFABS(base) * adx;
175  while (++x < x1) {
176  y += base;
177  err += ady;
178  if (err >= 0) {
179  err -= adx;
180  y += sy;
181  }
182  buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
183  }
184  }
185 }
186 
188  uint16_t *y_list, int *flag,
189  int multiplier, float *out, int samples)
190 {
191  int lx, ly, i;
192  lx = 0;
193  ly = y_list[0] * multiplier;
194  for (i = 1; i < values; i++) {
195  int pos = list[i].sort;
196  if (flag[pos]) {
197  int x1 = list[pos].x;
198  int y1 = y_list[pos] * multiplier;
199  if (lx < samples)
200  render_line(lx, ly, FFMIN(x1,samples), y1, out);
201  lx = x1;
202  ly = y1;
203  }
204  if (lx >= samples)
205  break;
206  }
207  if (lx < samples)
208  render_line(lx, ly, samples, ly, out);
209 }
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:54
unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
Definition: vorbis.c:34
int flag
Definition: cpu.c:35
av_log(ac->avr, AV_LOG_TRACE, "%d samples - audio_convert: %s to %s (%s)\, len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt), use_generic ? ac->func_descr_generic :ac->func_descr)
const float ff_vorbis_floor1_inverse_db_table[256]
Definition: vorbis_data.c:2123
uint16_t sort
Definition: vorbis.h:34
uint8_t bits
Definition: crc.c:252
uint8_t
static void render_line(int x0, int y0, int x1, int y1, float *buf)
Definition: vorbis.c:160
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:124
uint16_t x
Definition: vorbis.h:33
#define FFMIN(a, b)
Definition: common.h:66
int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
Definition: vorbis.c:52
#define FFABS(a)
Definition: common.h:61
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1409
uint16_t low
Definition: vorbis.h:35
uint16_t high
Definition: vorbis.h:36
common internal and external API header
static uint8_t tmp[8]
Definition: des.c:38
static void render_line_unrolled(intptr_t x, int y, int x1, intptr_t sy, int ady, int adx, float *buf)
Definition: vorbis.c:137
void ff_vorbis_floor1_render_list(vorbis_floor1_entry *list, int values, uint16_t *y_list, int *flag, int multiplier, float *out, int samples)
Definition: vorbis.c:187
FILE * out
Definition: movenc.c:54
Definition: vorbis.h:32
int ff_vorbis_ready_floor1_list(AVCodecContext *avctx, vorbis_floor1_entry *list, int values)
Definition: vorbis.c:97