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vsrc_cellauto.c
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1 /*
2  * Copyright (c) Stefano Sabatini 2011
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * cellular automaton video source, based on Stephen Wolfram "experimentus crucis"
24  */
25 
26 /* #define DEBUG */
27 
28 #include "libavutil/file.h"
29 #include "libavutil/lfg.h"
30 #include "libavutil/opt.h"
31 #include "libavutil/parseutils.h"
32 #include "libavutil/random_seed.h"
33 #include "libavutil/avstring.h"
34 #include "avfilter.h"
35 #include "internal.h"
36 #include "formats.h"
37 #include "video.h"
38 
39 typedef struct {
40  const AVClass *class;
41  int w, h;
42  char *filename;
43  char *rule_str;
45  size_t file_bufsize;
47  int buf_prev_row_idx, buf_row_idx;
49  uint64_t pts;
52  uint32_t random_seed;
53  int stitch, scroll, start_full;
54  int64_t generation; ///< the generation number, starting from 0
56  char *pattern;
58 
59 #define OFFSET(x) offsetof(CellAutoContext, x)
60 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
61 
62 static const AVOption cellauto_options[] = {
63  { "filename", "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
64  { "f", "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
65  { "pattern", "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
66  { "p", "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
67  { "rate", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
68  { "r", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
69  { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
70  { "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
71  { "rule", "set rule", OFFSET(rule), AV_OPT_TYPE_INT, {.i64 = 110}, 0, 255, FLAGS },
72  { "random_fill_ratio", "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl = 1/M_PHI}, 0, 1, FLAGS },
73  { "ratio", "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl = 1/M_PHI}, 0, 1, FLAGS },
74  { "random_seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
75  { "seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
76  { "scroll", "scroll pattern downward", OFFSET(scroll), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, FLAGS },
77  { "start_full", "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, FLAGS },
78  { "full", "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, FLAGS },
79  { "stitch", "stitch boundaries", OFFSET(stitch), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, FLAGS },
80  { NULL }
81 };
82 
83 AVFILTER_DEFINE_CLASS(cellauto);
84 
85 #ifdef DEBUG
86 static void show_cellauto_row(AVFilterContext *ctx)
87 {
88  CellAutoContext *cellauto = ctx->priv;
89  int i;
90  uint8_t *row = cellauto->buf + cellauto->w * cellauto->buf_row_idx;
91  char *line = av_malloc(cellauto->w + 1);
92  if (!line)
93  return;
94 
95  for (i = 0; i < cellauto->w; i++)
96  line[i] = row[i] ? '@' : ' ';
97  line[i] = 0;
98  av_log(ctx, AV_LOG_DEBUG, "generation:%"PRId64" row:%s|\n", cellauto->generation, line);
99  av_free(line);
100 }
101 #endif
102 
104 {
105  CellAutoContext *cellauto = ctx->priv;
106  char *p;
107  int i, w = 0;
108 
109  w = strlen(cellauto->pattern);
110  av_log(ctx, AV_LOG_DEBUG, "w:%d\n", w);
111 
112  if (cellauto->w) {
113  if (w > cellauto->w) {
114  av_log(ctx, AV_LOG_ERROR,
115  "The specified width is %d which cannot contain the provided string width of %d\n",
116  cellauto->w, w);
117  return AVERROR(EINVAL);
118  }
119  } else {
120  /* width was not specified, set it to width of the provided row */
121  cellauto->w = w;
122  cellauto->h = (double)cellauto->w * M_PHI;
123  }
124 
125  cellauto->buf = av_mallocz_array(sizeof(uint8_t) * cellauto->w, cellauto->h);
126  if (!cellauto->buf)
127  return AVERROR(ENOMEM);
128 
129  /* fill buf */
130  p = cellauto->pattern;
131  for (i = (cellauto->w - w)/2;; i++) {
132  av_log(ctx, AV_LOG_DEBUG, "%d %c\n", i, *p == '\n' ? 'N' : *p);
133  if (*p == '\n' || !*p)
134  break;
135  else
136  cellauto->buf[i] = !!av_isgraph(*(p++));
137  }
138 
139  return 0;
140 }
141 
143 {
144  CellAutoContext *cellauto = ctx->priv;
145  int ret;
146 
147  ret = av_file_map(cellauto->filename,
148  &cellauto->file_buf, &cellauto->file_bufsize, 0, ctx);
149  if (ret < 0)
150  return ret;
151 
152  /* create a string based on the read file */
153  cellauto->pattern = av_malloc(cellauto->file_bufsize + 1);
154  if (!cellauto->pattern)
155  return AVERROR(ENOMEM);
156  memcpy(cellauto->pattern, cellauto->file_buf, cellauto->file_bufsize);
157  cellauto->pattern[cellauto->file_bufsize] = 0;
158 
159  return init_pattern_from_string(ctx);
160 }
161 
162 static av_cold int init(AVFilterContext *ctx)
163 {
164  CellAutoContext *cellauto = ctx->priv;
165  int ret;
166 
167  if (!cellauto->w && !cellauto->filename && !cellauto->pattern)
168  av_opt_set(cellauto, "size", "320x518", 0);
169 
170  if (cellauto->filename && cellauto->pattern) {
171  av_log(ctx, AV_LOG_ERROR, "Only one of the filename or pattern options can be used\n");
172  return AVERROR(EINVAL);
173  }
174 
175  if (cellauto->filename) {
176  if ((ret = init_pattern_from_file(ctx)) < 0)
177  return ret;
178  } else if (cellauto->pattern) {
179  if ((ret = init_pattern_from_string(ctx)) < 0)
180  return ret;
181  } else {
182  /* fill the first row randomly */
183  int i;
184 
185  cellauto->buf = av_mallocz_array(sizeof(uint8_t) * cellauto->w, cellauto->h);
186  if (!cellauto->buf)
187  return AVERROR(ENOMEM);
188  if (cellauto->random_seed == -1)
189  cellauto->random_seed = av_get_random_seed();
190 
191  av_lfg_init(&cellauto->lfg, cellauto->random_seed);
192 
193  for (i = 0; i < cellauto->w; i++) {
194  double r = (double)av_lfg_get(&cellauto->lfg) / UINT32_MAX;
195  if (r <= cellauto->random_fill_ratio)
196  cellauto->buf[i] = 1;
197  }
198  }
199 
200  av_log(ctx, AV_LOG_VERBOSE,
201  "s:%dx%d r:%d/%d rule:%d stitch:%d scroll:%d full:%d seed:%u\n",
202  cellauto->w, cellauto->h, cellauto->frame_rate.num, cellauto->frame_rate.den,
203  cellauto->rule, cellauto->stitch, cellauto->scroll, cellauto->start_full,
204  cellauto->random_seed);
205  return 0;
206 }
207 
208 static av_cold void uninit(AVFilterContext *ctx)
209 {
210  CellAutoContext *cellauto = ctx->priv;
211 
212  av_file_unmap(cellauto->file_buf, cellauto->file_bufsize);
213  av_freep(&cellauto->buf);
214  av_freep(&cellauto->pattern);
215 }
216 
217 static int config_props(AVFilterLink *outlink)
218 {
219  CellAutoContext *cellauto = outlink->src->priv;
220 
221  outlink->w = cellauto->w;
222  outlink->h = cellauto->h;
223  outlink->time_base = av_inv_q(cellauto->frame_rate);
224 
225  return 0;
226 }
227 
228 static void evolve(AVFilterContext *ctx)
229 {
230  CellAutoContext *cellauto = ctx->priv;
231  int i, v, pos[3];
232  uint8_t *row, *prev_row = cellauto->buf + cellauto->buf_row_idx * cellauto->w;
233  enum { NW, N, NE };
234 
235  cellauto->buf_prev_row_idx = cellauto->buf_row_idx;
236  cellauto->buf_row_idx = cellauto->buf_row_idx == cellauto->h-1 ? 0 : cellauto->buf_row_idx+1;
237  row = cellauto->buf + cellauto->w * cellauto->buf_row_idx;
238 
239  for (i = 0; i < cellauto->w; i++) {
240  if (cellauto->stitch) {
241  pos[NW] = i-1 < 0 ? cellauto->w-1 : i-1;
242  pos[N] = i;
243  pos[NE] = i+1 == cellauto->w ? 0 : i+1;
244  v = prev_row[pos[NW]]<<2 | prev_row[pos[N]]<<1 | prev_row[pos[NE]];
245  } else {
246  v = 0;
247  v|= i-1 >= 0 ? prev_row[i-1]<<2 : 0;
248  v|= prev_row[i ]<<1 ;
249  v|= i+1 < cellauto->w ? prev_row[i+1] : 0;
250  }
251  row[i] = !!(cellauto->rule & (1<<v));
252  av_dlog(ctx, "i:%d context:%c%c%c -> cell:%d\n", i,
253  v&4?'@':' ', v&2?'@':' ', v&1?'@':' ', row[i]);
254  }
255 
256  cellauto->generation++;
257 }
258 
259 static void fill_picture(AVFilterContext *ctx, AVFrame *picref)
260 {
261  CellAutoContext *cellauto = ctx->priv;
262  int i, j, k, row_idx = 0;
263  uint8_t *p0 = picref->data[0];
264 
265  if (cellauto->scroll && cellauto->generation >= cellauto->h)
266  /* show on top the oldest row */
267  row_idx = (cellauto->buf_row_idx + 1) % cellauto->h;
268 
269  /* fill the output picture with the whole buffer */
270  for (i = 0; i < cellauto->h; i++) {
271  uint8_t byte = 0;
272  uint8_t *row = cellauto->buf + row_idx*cellauto->w;
273  uint8_t *p = p0;
274  for (k = 0, j = 0; j < cellauto->w; j++) {
275  byte |= row[j]<<(7-k++);
276  if (k==8 || j == cellauto->w-1) {
277  k = 0;
278  *p++ = byte;
279  byte = 0;
280  }
281  }
282  row_idx = (row_idx + 1) % cellauto->h;
283  p0 += picref->linesize[0];
284  }
285 }
286 
287 static int request_frame(AVFilterLink *outlink)
288 {
289  CellAutoContext *cellauto = outlink->src->priv;
290  AVFrame *picref = ff_get_video_buffer(outlink, cellauto->w, cellauto->h);
291  if (!picref)
292  return AVERROR(ENOMEM);
293  picref->sample_aspect_ratio = (AVRational) {1, 1};
294  if (cellauto->generation == 0 && cellauto->start_full) {
295  int i;
296  for (i = 0; i < cellauto->h-1; i++)
297  evolve(outlink->src);
298  }
299  fill_picture(outlink->src, picref);
300  evolve(outlink->src);
301 
302  picref->pts = cellauto->pts++;
303 
304 #ifdef DEBUG
305  show_cellauto_row(outlink->src);
306 #endif
307  return ff_filter_frame(outlink, picref);
308 }
309 
311 {
312  static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE };
314  return 0;
315 }
316 
317 static const AVFilterPad cellauto_outputs[] = {
318  {
319  .name = "default",
320  .type = AVMEDIA_TYPE_VIDEO,
321  .request_frame = request_frame,
322  .config_props = config_props,
323  },
324  { NULL }
325 };
326 
328  .name = "cellauto",
329  .description = NULL_IF_CONFIG_SMALL("Create pattern generated by an elementary cellular automaton."),
330  .priv_size = sizeof(CellAutoContext),
331  .priv_class = &cellauto_class,
332  .init = init,
333  .uninit = uninit,
335  .inputs = NULL,
336  .outputs = cellauto_outputs,
337 };