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vsrc_life.c
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1 /*
2  * Copyright (c) Stefano Sabatini 2010
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  * life video source, based on John Conways' Life Game
24  */
25 
26 /* #define DEBUG */
27 
28 #include "libavutil/file.h"
29 #include "libavutil/intreadwrite.h"
30 #include "libavutil/lfg.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/parseutils.h"
33 #include "libavutil/random_seed.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;
44  uint8_t *file_buf;
45  size_t file_bufsize;
46 
47  /**
48  * The two grid state buffers.
49  *
50  * A 0xFF (ALIVE_CELL) value means the cell is alive (or new born), while
51  * the decreasing values from 0xFE to 0 means the cell is dead; the range
52  * of values is used for the slow death effect, or mold (0xFE means dead,
53  * 0xFD means very dead, 0xFC means very very dead... and 0x00 means
54  * definitely dead/mold).
55  */
56  uint8_t *buf[2];
57 
58  uint8_t buf_idx;
59  uint16_t stay_rule; ///< encode the behavior for filled cells
60  uint16_t born_rule; ///< encode the behavior for empty cells
61  uint64_t pts;
62  AVRational time_base;
63  char *rate; ///< video frame rate
64  double random_fill_ratio;
65  uint32_t random_seed;
66  int stitch;
67  int mold;
68  char *life_color_str;
69  char *death_color_str;
70  char *mold_color_str;
71  uint8_t life_color[4];
72  uint8_t death_color[4];
73  uint8_t mold_color[4];
74  AVLFG lfg;
75  void (*draw)(AVFilterContext*, AVFilterBufferRef*);
76 } LifeContext;
77 
78 #define ALIVE_CELL 0xFF
79 #define OFFSET(x) offsetof(LifeContext, x)
80 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
81 
82 static const AVOption life_options[] = {
83  { "filename", "set source file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
84  { "f", "set source file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
85  { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
86  { "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
87  { "rate", "set video rate", OFFSET(rate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, FLAGS },
88  { "r", "set video rate", OFFSET(rate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, FLAGS },
89  { "rule", "set rule", OFFSET(rule_str), AV_OPT_TYPE_STRING, {.str = "B3/S23"}, CHAR_MIN, CHAR_MAX, FLAGS },
90  { "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 },
91  { "ratio", "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl=1/M_PHI}, 0, 1, FLAGS },
92  { "random_seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64=-1}, -1, UINT32_MAX, FLAGS },
93  { "seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64=-1}, -1, UINT32_MAX, FLAGS },
94  { "stitch", "stitch boundaries", OFFSET(stitch), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
95  { "mold", "set mold speed for dead cells", OFFSET(mold), AV_OPT_TYPE_INT, {.i64=0}, 0, 0xFF, FLAGS },
96  { "life_color", "set life color", OFFSET( life_color_str), AV_OPT_TYPE_STRING, {.str="white"}, CHAR_MIN, CHAR_MAX, FLAGS },
97  { "death_color", "set death color", OFFSET(death_color_str), AV_OPT_TYPE_STRING, {.str="black"}, CHAR_MIN, CHAR_MAX, FLAGS },
98  { "mold_color", "set mold color", OFFSET( mold_color_str), AV_OPT_TYPE_STRING, {.str="black"}, CHAR_MIN, CHAR_MAX, FLAGS },
99  { NULL },
100 };
101 
102 AVFILTER_DEFINE_CLASS(life);
103 
104 static int parse_rule(uint16_t *born_rule, uint16_t *stay_rule,
105  const char *rule_str, void *log_ctx)
106 {
107  char *tail;
108  const char *p = rule_str;
109  *born_rule = 0;
110  *stay_rule = 0;
111 
112  if (strchr("bBsS", *p)) {
113  /* parse rule as a Born / Stay Alive code, see
114  * http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life */
115  do {
116  uint16_t *rule = (*p == 'b' || *p == 'B') ? born_rule : stay_rule;
117  p++;
118  while (*p >= '0' && *p <= '8') {
119  *rule += 1<<(*p - '0');
120  p++;
121  }
122  if (*p != '/')
123  break;
124  p++;
125  } while (strchr("bBsS", *p));
126 
127  if (*p)
128  goto error;
129  } else {
130  /* parse rule as a number, expressed in the form STAY|(BORN<<9),
131  * where STAY and BORN encode the corresponding 9-bits rule */
132  long int rule = strtol(rule_str, &tail, 10);
133  if (*tail)
134  goto error;
135  *born_rule = ((1<<9)-1) & rule;
136  *stay_rule = rule >> 9;
137  }
138 
139  return 0;
140 
141 error:
142  av_log(log_ctx, AV_LOG_ERROR, "Invalid rule code '%s' provided\n", rule_str);
143  return AVERROR(EINVAL);
144 }
145 
146 #ifdef DEBUG
147 static void show_life_grid(AVFilterContext *ctx)
148 {
149  LifeContext *life = ctx->priv;
150  int i, j;
151 
152  char *line = av_malloc(life->w + 1);
153  if (!line)
154  return;
155  for (i = 0; i < life->h; i++) {
156  for (j = 0; j < life->w; j++)
157  line[j] = life->buf[life->buf_idx][i*life->w + j] == ALIVE_CELL ? '@' : ' ';
158  line[j] = 0;
159  av_log(ctx, AV_LOG_DEBUG, "%3d: %s\n", i, line);
160  }
161  av_free(line);
162 }
163 #endif
164 
165 static int init_pattern_from_file(AVFilterContext *ctx)
166 {
167  LifeContext *life = ctx->priv;
168  char *p;
169  int ret, i, i0, j, h = 0, w, max_w = 0;
170 
171  if ((ret = av_file_map(life->filename, &life->file_buf, &life->file_bufsize,
172  0, ctx)) < 0)
173  return ret;
174  av_freep(&life->filename);
175 
176  /* prescan file to get the number of lines and the maximum width */
177  w = 0;
178  for (i = 0; i < life->file_bufsize; i++) {
179  if (life->file_buf[i] == '\n') {
180  h++; max_w = FFMAX(w, max_w); w = 0;
181  } else {
182  w++;
183  }
184  }
185  av_log(ctx, AV_LOG_DEBUG, "h:%d max_w:%d\n", h, max_w);
186 
187  if (life->w) {
188  if (max_w > life->w || h > life->h) {
189  av_log(ctx, AV_LOG_ERROR,
190  "The specified size is %dx%d which cannot contain the provided file size of %dx%d\n",
191  life->w, life->h, max_w, h);
192  return AVERROR(EINVAL);
193  }
194  } else {
195  /* size was not specified, set it to size of the grid */
196  life->w = max_w;
197  life->h = h;
198  }
199 
200  if (!(life->buf[0] = av_mallocz(sizeof(char) * life->h * life->w)) ||
201  !(life->buf[1] = av_mallocz(sizeof(char) * life->h * life->w))) {
202  av_free(life->buf[0]);
203  av_free(life->buf[1]);
204  return AVERROR(ENOMEM);
205  }
206 
207  /* fill buf[0] */
208  p = life->file_buf;
209  for (i0 = 0, i = (life->h - h)/2; i0 < h; i0++, i++) {
210  for (j = (life->w - max_w)/2;; j++) {
211  av_log(ctx, AV_LOG_DEBUG, "%d:%d %c\n", i, j, *p == '\n' ? 'N' : *p);
212  if (*p == '\n') {
213  p++; break;
214  } else
215  life->buf[0][i*life->w + j] = isgraph(*(p++)) ? ALIVE_CELL : 0;
216  }
217  }
218  life->buf_idx = 0;
219 
220  return 0;
221 }
222 
223 static int init(AVFilterContext *ctx, const char *args)
224 {
225  LifeContext *life = ctx->priv;
226  AVRational frame_rate;
227  int ret;
228 
229  life->class = &life_class;
230  av_opt_set_defaults(life);
231 
232  if ((ret = av_set_options_string(life, args, "=", ":")) < 0)
233  return ret;
234 
235  if ((ret = av_parse_video_rate(&frame_rate, life->rate)) < 0) {
236  av_log(ctx, AV_LOG_ERROR, "Invalid frame rate: %s\n", life->rate);
237  return AVERROR(EINVAL);
238  }
239  av_freep(&life->rate);
240 
241  if (!life->w && !life->filename)
242  av_opt_set(life, "size", "320x240", 0);
243 
244  if ((ret = parse_rule(&life->born_rule, &life->stay_rule, life->rule_str, ctx)) < 0)
245  return ret;
246 
247 #define PARSE_COLOR(name) do { \
248  if ((ret = av_parse_color(life->name ## _color, life->name ## _color_str, -1, ctx))) { \
249  av_log(ctx, AV_LOG_ERROR, "Invalid " #name " color '%s'\n", \
250  life->name ## _color_str); \
251  return ret; \
252  } \
253  av_freep(&life->name ## _color_str); \
254 } while (0)
255 
256  PARSE_COLOR(life);
257  PARSE_COLOR(death);
258  PARSE_COLOR(mold);
259 
260  if (!life->mold && memcmp(life->mold_color, "\x00\x00\x00", 3))
261  av_log(ctx, AV_LOG_WARNING,
262  "Mold color is set while mold isn't, ignoring the color.\n");
263 
264  life->time_base.num = frame_rate.den;
265  life->time_base.den = frame_rate.num;
266 
267  if (!life->filename) {
268  /* fill the grid randomly */
269  int i;
270 
271  if (!(life->buf[0] = av_mallocz(sizeof(char) * life->h * life->w)) ||
272  !(life->buf[1] = av_mallocz(sizeof(char) * life->h * life->w))) {
273  av_free(life->buf[0]);
274  av_free(life->buf[1]);
275  return AVERROR(ENOMEM);
276  }
277  if (life->random_seed == -1)
278  life->random_seed = av_get_random_seed();
279 
280  av_lfg_init(&life->lfg, life->random_seed);
281 
282  for (i = 0; i < life->w * life->h; i++) {
283  double r = (double)av_lfg_get(&life->lfg) / UINT32_MAX;
284  if (r <= life->random_fill_ratio)
285  life->buf[0][i] = ALIVE_CELL;
286  }
287  life->buf_idx = 0;
288  } else {
289  if ((ret = init_pattern_from_file(ctx)) < 0)
290  return ret;
291  }
292 
293  av_log(ctx, AV_LOG_VERBOSE,
294  "s:%dx%d r:%d/%d rule:%s stay_rule:%d born_rule:%d stitch:%d seed:%u\n",
295  life->w, life->h, frame_rate.num, frame_rate.den,
296  life->rule_str, life->stay_rule, life->born_rule, life->stitch,
297  life->random_seed);
298  return 0;
299 }
300 
301 static av_cold void uninit(AVFilterContext *ctx)
302 {
303  LifeContext *life = ctx->priv;
304 
305  av_file_unmap(life->file_buf, life->file_bufsize);
306  av_freep(&life->rule_str);
307  av_freep(&life->buf[0]);
308  av_freep(&life->buf[1]);
309 }
310 
311 static int config_props(AVFilterLink *outlink)
312 {
313  LifeContext *life = outlink->src->priv;
314 
315  outlink->w = life->w;
316  outlink->h = life->h;
317  outlink->time_base = life->time_base;
318 
319  return 0;
320 }
321 
322 static void evolve(AVFilterContext *ctx)
323 {
324  LifeContext *life = ctx->priv;
325  int i, j;
326  uint8_t *oldbuf = life->buf[ life->buf_idx];
327  uint8_t *newbuf = life->buf[!life->buf_idx];
328 
329  enum { NW, N, NE, W, E, SW, S, SE };
330 
331  /* evolve the grid */
332  for (i = 0; i < life->h; i++) {
333  for (j = 0; j < life->w; j++) {
334  int pos[8][2], n, alive, cell;
335  if (life->stitch) {
336  pos[NW][0] = (i-1) < 0 ? life->h-1 : i-1; pos[NW][1] = (j-1) < 0 ? life->w-1 : j-1;
337  pos[N ][0] = (i-1) < 0 ? life->h-1 : i-1; pos[N ][1] = j ;
338  pos[NE][0] = (i-1) < 0 ? life->h-1 : i-1; pos[NE][1] = (j+1) == life->w ? 0 : j+1;
339  pos[W ][0] = i ; pos[W ][1] = (j-1) < 0 ? life->w-1 : j-1;
340  pos[E ][0] = i ; pos[E ][1] = (j+1) == life->w ? 0 : j+1;
341  pos[SW][0] = (i+1) == life->h ? 0 : i+1; pos[SW][1] = (j-1) < 0 ? life->w-1 : j-1;
342  pos[S ][0] = (i+1) == life->h ? 0 : i+1; pos[S ][1] = j ;
343  pos[SE][0] = (i+1) == life->h ? 0 : i+1; pos[SE][1] = (j+1) == life->w ? 0 : j+1;
344  } else {
345  pos[NW][0] = (i-1) < 0 ? -1 : i-1; pos[NW][1] = (j-1) < 0 ? -1 : j-1;
346  pos[N ][0] = (i-1) < 0 ? -1 : i-1; pos[N ][1] = j ;
347  pos[NE][0] = (i-1) < 0 ? -1 : i-1; pos[NE][1] = (j+1) == life->w ? -1 : j+1;
348  pos[W ][0] = i ; pos[W ][1] = (j-1) < 0 ? -1 : j-1;
349  pos[E ][0] = i ; pos[E ][1] = (j+1) == life->w ? -1 : j+1;
350  pos[SW][0] = (i+1) == life->h ? -1 : i+1; pos[SW][1] = (j-1) < 0 ? -1 : j-1;
351  pos[S ][0] = (i+1) == life->h ? -1 : i+1; pos[S ][1] = j ;
352  pos[SE][0] = (i+1) == life->h ? -1 : i+1; pos[SE][1] = (j+1) == life->w ? -1 : j+1;
353  }
354 
355  /* compute the number of live neighbor cells */
356  n = (pos[NW][0] == -1 || pos[NW][1] == -1 ? 0 : oldbuf[pos[NW][0]*life->w + pos[NW][1]] == ALIVE_CELL) +
357  (pos[N ][0] == -1 || pos[N ][1] == -1 ? 0 : oldbuf[pos[N ][0]*life->w + pos[N ][1]] == ALIVE_CELL) +
358  (pos[NE][0] == -1 || pos[NE][1] == -1 ? 0 : oldbuf[pos[NE][0]*life->w + pos[NE][1]] == ALIVE_CELL) +
359  (pos[W ][0] == -1 || pos[W ][1] == -1 ? 0 : oldbuf[pos[W ][0]*life->w + pos[W ][1]] == ALIVE_CELL) +
360  (pos[E ][0] == -1 || pos[E ][1] == -1 ? 0 : oldbuf[pos[E ][0]*life->w + pos[E ][1]] == ALIVE_CELL) +
361  (pos[SW][0] == -1 || pos[SW][1] == -1 ? 0 : oldbuf[pos[SW][0]*life->w + pos[SW][1]] == ALIVE_CELL) +
362  (pos[S ][0] == -1 || pos[S ][1] == -1 ? 0 : oldbuf[pos[S ][0]*life->w + pos[S ][1]] == ALIVE_CELL) +
363  (pos[SE][0] == -1 || pos[SE][1] == -1 ? 0 : oldbuf[pos[SE][0]*life->w + pos[SE][1]] == ALIVE_CELL);
364  cell = oldbuf[i*life->w + j];
365  alive = 1<<n & (cell == ALIVE_CELL ? life->stay_rule : life->born_rule);
366  if (alive) *newbuf = ALIVE_CELL; // new cell is alive
367  else if (cell) *newbuf = cell - 1; // new cell is dead and in the process of mold
368  else *newbuf = 0; // new cell is definitely dead
369  av_dlog(ctx, "i:%d j:%d live_neighbors:%d cell:%d -> cell:%d\n", i, j, n, cell, *newbuf);
370  newbuf++;
371  }
372  }
373 
374  life->buf_idx = !life->buf_idx;
375 }
376 
377 static void fill_picture_monoblack(AVFilterContext *ctx, AVFilterBufferRef *picref)
378 {
379  LifeContext *life = ctx->priv;
380  uint8_t *buf = life->buf[life->buf_idx];
381  int i, j, k;
382 
383  /* fill the output picture with the old grid buffer */
384  for (i = 0; i < life->h; i++) {
385  uint8_t byte = 0;
386  uint8_t *p = picref->data[0] + i * picref->linesize[0];
387  for (k = 0, j = 0; j < life->w; j++) {
388  byte |= (buf[i*life->w+j] == ALIVE_CELL)<<(7-k++);
389  if (k==8 || j == life->w-1) {
390  k = 0;
391  *p++ = byte;
392  byte = 0;
393  }
394  }
395  }
396 }
397 
398 // divide by 255 and round to nearest
399 // apply a fast variant: (X+127)/255 = ((X+127)*257+257)>>16 = ((X+128)*257)>>16
400 #define FAST_DIV255(x) ((((x) + 128) * 257) >> 16)
401 
402 static void fill_picture_rgb(AVFilterContext *ctx, AVFilterBufferRef *picref)
403 {
404  LifeContext *life = ctx->priv;
405  uint8_t *buf = life->buf[life->buf_idx];
406  int i, j;
407 
408  /* fill the output picture with the old grid buffer */
409  for (i = 0; i < life->h; i++) {
410  uint8_t *p = picref->data[0] + i * picref->linesize[0];
411  for (j = 0; j < life->w; j++) {
412  uint8_t v = buf[i*life->w + j];
413  if (life->mold && v != ALIVE_CELL) {
414  const uint8_t *c1 = life-> mold_color;
415  const uint8_t *c2 = life->death_color;
416  int death_age = FFMIN((0xff - v) * life->mold, 0xff);
417  *p++ = FAST_DIV255((c2[0] << 8) + ((int)c1[0] - (int)c2[0]) * death_age);
418  *p++ = FAST_DIV255((c2[1] << 8) + ((int)c1[1] - (int)c2[1]) * death_age);
419  *p++ = FAST_DIV255((c2[2] << 8) + ((int)c1[2] - (int)c2[2]) * death_age);
420  } else {
421  const uint8_t *c = v == ALIVE_CELL ? life->life_color : life->death_color;
422  AV_WB24(p, c[0]<<16 | c[1]<<8 | c[2]);
423  p += 3;
424  }
425  }
426  }
427 }
428 
429 static int request_frame(AVFilterLink *outlink)
430 {
431  LifeContext *life = outlink->src->priv;
432  AVFilterBufferRef *picref = ff_get_video_buffer(outlink, AV_PERM_WRITE, life->w, life->h);
433  picref->video->sample_aspect_ratio = (AVRational) {1, 1};
434  picref->pts = life->pts++;
435  picref->pos = -1;
436 
437  life->draw(outlink->src, picref);
438  evolve(outlink->src);
439 #ifdef DEBUG
440  show_life_grid(outlink->src);
441 #endif
442  ff_filter_frame(outlink, picref);
443 
444  return 0;
445 }
446 
447 static int query_formats(AVFilterContext *ctx)
448 {
449  LifeContext *life = ctx->priv;
450  enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_NONE, AV_PIX_FMT_NONE };
451  if (life->mold || memcmp(life-> life_color, "\xff\xff\xff", 3)
452  || memcmp(life->death_color, "\x00\x00\x00", 3)) {
453  pix_fmts[0] = AV_PIX_FMT_RGB24;
454  life->draw = fill_picture_rgb;
455  } else {
456  pix_fmts[0] = AV_PIX_FMT_MONOBLACK;
457  life->draw = fill_picture_monoblack;
458  }
459  ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
460  return 0;
461 }
462 
463 static const AVFilterPad life_outputs[] = {
464  {
465  .name = "default",
466  .type = AVMEDIA_TYPE_VIDEO,
467  .request_frame = request_frame,
468  .config_props = config_props,
469  },
470  { NULL}
471 };
472 
473 AVFilter avfilter_vsrc_life = {
474  .name = "life",
475  .description = NULL_IF_CONFIG_SMALL("Create life."),
476  .priv_size = sizeof(LifeContext),
477  .init = init,
478  .uninit = uninit,
479  .query_formats = query_formats,
480  .inputs = NULL,
481  .outputs = life_outputs,
482  .priv_class = &life_class,
483 };
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