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/internal.h"
30 #include "libavutil/lfg.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/parseutils.h"
33 #include "libavutil/random_seed.h"
34 #include "libavutil/avstring.h"
35 #include "avfilter.h"
36 #include "internal.h"
37 #include "formats.h"
38 #include "video.h"
39
40 typedef struct CellAutoContext {
41 const AVClass *class;
42 int w, h;
43 char *filename;
44 char *rule_str;
45 uint8_t *file_buf;
46 size_t file_bufsize;
47 uint8_t *buf;
48 int buf_prev_row_idx, buf_row_idx;
49 uint8_t rule;
50 uint64_t pts;
51 AVRational frame_rate;
52 double random_fill_ratio;
53 int64_t random_seed;
54 int stitch, scroll, start_full;
55 int64_t generation; ///< the generation number, starting from 0
56 AVLFG lfg;
57 char *pattern;
58 } CellAutoContext;
59
60 #define OFFSET(x) offsetof(CellAutoContext, x)
61 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
62
63 static const AVOption cellauto_options[] = {
64 { "filename", "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
65 { "f", "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
66 { "pattern", "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
67 { "p", "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
68 { "rate", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, FLAGS },
69 { "r", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, FLAGS },
70 { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
71 { "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
72 { "rule", "set rule", OFFSET(rule), AV_OPT_TYPE_INT, {.i64 = 110}, 0, 255, FLAGS },
73 { "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 },
74 { "ratio", "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl = 1/M_PHI}, 0, 1, FLAGS },
75 { "random_seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT64, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
76 { "seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT64, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
77 { "scroll", "scroll pattern downward", OFFSET(scroll), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
78 { "start_full", "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS },
79 { "full", "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
80 { "stitch", "stitch boundaries", OFFSET(stitch), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
81 { NULL }
82 };
83
84 AVFILTER_DEFINE_CLASS(cellauto);
85
86 #ifdef DEBUG
show_cellauto_row(AVFilterContext * ctx)87 static void show_cellauto_row(AVFilterContext *ctx)
88 {
89 CellAutoContext *s = ctx->priv;
90 int i;
91 uint8_t *row = s->buf + s->w * s->buf_row_idx;
92 char *line = av_malloc(s->w + 1);
93 if (!line)
94 return;
95
96 for (i = 0; i < s->w; i++)
97 line[i] = row[i] ? '@' : ' ';
98 line[i] = 0;
99 av_log(ctx, AV_LOG_DEBUG, "generation:%"PRId64" row:%s|\n", s->generation, line);
100 av_free(line);
101 }
102 #endif
103
init_pattern_from_string(AVFilterContext * ctx)104 static int init_pattern_from_string(AVFilterContext *ctx)
105 {
106 CellAutoContext *s = ctx->priv;
107 char *p;
108 int i, w = 0;
109
110 w = strlen(s->pattern);
111 av_log(ctx, AV_LOG_DEBUG, "w:%d\n", w);
112
113 if (s->w) {
114 if (w > s->w) {
115 av_log(ctx, AV_LOG_ERROR,
116 "The specified width is %d which cannot contain the provided string width of %d\n",
117 s->w, w);
118 return AVERROR(EINVAL);
119 }
120 } else {
121 /* width was not specified, set it to width of the provided row */
122 s->w = w;
123 s->h = (double)s->w * M_PHI;
124 }
125
126 s->buf = av_calloc(s->w, s->h * sizeof(*s->buf));
127 if (!s->buf)
128 return AVERROR(ENOMEM);
129
130 /* fill buf */
131 p = s->pattern;
132 for (i = (s->w - w)/2;; i++) {
133 av_log(ctx, AV_LOG_DEBUG, "%d %c\n", i, *p == '\n' ? 'N' : *p);
134 if (*p == '\n' || !*p)
135 break;
136 else
137 s->buf[i] = !!av_isgraph(*(p++));
138 }
139
140 return 0;
141 }
142
init_pattern_from_file(AVFilterContext * ctx)143 static int init_pattern_from_file(AVFilterContext *ctx)
144 {
145 CellAutoContext *s = ctx->priv;
146 int ret;
147
148 ret = av_file_map(s->filename,
149 &s->file_buf, &s->file_bufsize, 0, ctx);
150 if (ret < 0)
151 return ret;
152
153 /* create a string based on the read file */
154 s->pattern = av_malloc(s->file_bufsize + 1);
155 if (!s->pattern)
156 return AVERROR(ENOMEM);
157 memcpy(s->pattern, s->file_buf, s->file_bufsize);
158 s->pattern[s->file_bufsize] = 0;
159
160 return init_pattern_from_string(ctx);
161 }
162
init(AVFilterContext * ctx)163 static av_cold int init(AVFilterContext *ctx)
164 {
165 CellAutoContext *s = ctx->priv;
166 int ret;
167
168 if (!s->w && !s->filename && !s->pattern)
169 av_opt_set(s, "size", "320x518", 0);
170
171 if (s->filename && s->pattern) {
172 av_log(ctx, AV_LOG_ERROR, "Only one of the filename or pattern options can be used\n");
173 return AVERROR(EINVAL);
174 }
175
176 if (s->filename) {
177 if ((ret = init_pattern_from_file(ctx)) < 0)
178 return ret;
179 } else if (s->pattern) {
180 if ((ret = init_pattern_from_string(ctx)) < 0)
181 return ret;
182 } else {
183 /* fill the first row randomly */
184 int i;
185
186 s->buf = av_calloc(s->w, s->h * sizeof(*s->buf));
187 if (!s->buf)
188 return AVERROR(ENOMEM);
189 if (s->random_seed == -1)
190 s->random_seed = av_get_random_seed();
191
192 av_lfg_init(&s->lfg, s->random_seed);
193
194 for (i = 0; i < s->w; i++) {
195 double r = (double)av_lfg_get(&s->lfg) / UINT32_MAX;
196 if (r <= s->random_fill_ratio)
197 s->buf[i] = 1;
198 }
199 }
200
201 av_log(ctx, AV_LOG_VERBOSE,
202 "s:%dx%d r:%d/%d rule:%d stitch:%d scroll:%d full:%d seed:%"PRId64"\n",
203 s->w, s->h, s->frame_rate.num, s->frame_rate.den,
204 s->rule, s->stitch, s->scroll, s->start_full,
205 s->random_seed);
206 return 0;
207 }
208
uninit(AVFilterContext * ctx)209 static av_cold void uninit(AVFilterContext *ctx)
210 {
211 CellAutoContext *s = ctx->priv;
212
213 av_file_unmap(s->file_buf, s->file_bufsize);
214 av_freep(&s->buf);
215 av_freep(&s->pattern);
216 }
217
config_props(AVFilterLink * outlink)218 static int config_props(AVFilterLink *outlink)
219 {
220 CellAutoContext *s = outlink->src->priv;
221
222 outlink->w = s->w;
223 outlink->h = s->h;
224 outlink->time_base = av_inv_q(s->frame_rate);
225 outlink->frame_rate = s->frame_rate;
226
227 return 0;
228 }
229
evolve(AVFilterContext * ctx)230 static void evolve(AVFilterContext *ctx)
231 {
232 CellAutoContext *s = ctx->priv;
233 int i, v, pos[3];
234 uint8_t *row, *prev_row = s->buf + s->buf_row_idx * s->w;
235 enum { NW, N, NE };
236
237 s->buf_prev_row_idx = s->buf_row_idx;
238 s->buf_row_idx = s->buf_row_idx == s->h-1 ? 0 : s->buf_row_idx+1;
239 row = s->buf + s->w * s->buf_row_idx;
240
241 for (i = 0; i < s->w; i++) {
242 if (s->stitch) {
243 pos[NW] = i-1 < 0 ? s->w-1 : i-1;
244 pos[N] = i;
245 pos[NE] = i+1 == s->w ? 0 : i+1;
246 v = prev_row[pos[NW]]<<2 | prev_row[pos[N]]<<1 | prev_row[pos[NE]];
247 } else {
248 v = 0;
249 v|= i-1 >= 0 ? prev_row[i-1]<<2 : 0;
250 v|= prev_row[i ]<<1 ;
251 v|= i+1 < s->w ? prev_row[i+1] : 0;
252 }
253 row[i] = !!(s->rule & (1<<v));
254 ff_dlog(ctx, "i:%d context:%c%c%c -> cell:%d\n", i,
255 v&4?'@':' ', v&2?'@':' ', v&1?'@':' ', row[i]);
256 }
257
258 s->generation++;
259 }
260
fill_picture(AVFilterContext * ctx,AVFrame * picref)261 static void fill_picture(AVFilterContext *ctx, AVFrame *picref)
262 {
263 CellAutoContext *s = ctx->priv;
264 int i, j, k, row_idx = 0;
265 uint8_t *p0 = picref->data[0];
266
267 if (s->scroll && s->generation >= s->h)
268 /* show on top the oldest row */
269 row_idx = (s->buf_row_idx + 1) % s->h;
270
271 /* fill the output picture with the whole buffer */
272 for (i = 0; i < s->h; i++) {
273 uint8_t byte = 0;
274 uint8_t *row = s->buf + row_idx*s->w;
275 uint8_t *p = p0;
276 for (k = 0, j = 0; j < s->w; j++) {
277 byte |= row[j]<<(7-k++);
278 if (k==8 || j == s->w-1) {
279 k = 0;
280 *p++ = byte;
281 byte = 0;
282 }
283 }
284 row_idx = (row_idx + 1) % s->h;
285 p0 += picref->linesize[0];
286 }
287 }
288
request_frame(AVFilterLink * outlink)289 static int request_frame(AVFilterLink *outlink)
290 {
291 CellAutoContext *s = outlink->src->priv;
292 AVFrame *picref = ff_get_video_buffer(outlink, s->w, s->h);
293 if (!picref)
294 return AVERROR(ENOMEM);
295 picref->sample_aspect_ratio = (AVRational) {1, 1};
296 if (s->generation == 0 && s->start_full) {
297 int i;
298 for (i = 0; i < s->h-1; i++)
299 evolve(outlink->src);
300 }
301 fill_picture(outlink->src, picref);
302 evolve(outlink->src);
303
304 picref->pts = s->pts++;
305
306 #ifdef DEBUG
307 show_cellauto_row(outlink->src);
308 #endif
309 return ff_filter_frame(outlink, picref);
310 }
311
312 static const AVFilterPad cellauto_outputs[] = {
313 {
314 .name = "default",
315 .type = AVMEDIA_TYPE_VIDEO,
316 .request_frame = request_frame,
317 .config_props = config_props,
318 },
319 };
320
321 const AVFilter ff_vsrc_cellauto = {
322 .name = "cellauto",
323 .description = NULL_IF_CONFIG_SMALL("Create pattern generated by an elementary cellular automaton."),
324 .priv_size = sizeof(CellAutoContext),
325 .priv_class = &cellauto_class,
326 .init = init,
327 .uninit = uninit,
328 .inputs = NULL,
329 FILTER_OUTPUTS(cellauto_outputs),
330 FILTER_SINGLE_PIXFMT(AV_PIX_FMT_MONOBLACK),
331 };
332