355 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			355 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (c) Stefano Sabatini 2011
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * cellular automaton video source, based on Stephen Wolfram "experimentus crucis"
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 */
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/* #define DEBUG */
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#include "libavutil/file.h"
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#include "libavutil/lfg.h"
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#include "libavutil/opt.h"
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#include "libavutil/parseutils.h"
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#include "libavutil/random_seed.h"
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#include "avfilter.h"
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#include "internal.h"
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#include "formats.h"
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#include "video.h"
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typedef struct {
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    const AVClass *class;
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    int w, h;
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    char *filename;
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    char *rule_str;
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    uint8_t *file_buf;
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    size_t file_bufsize;
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    uint8_t *buf;
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    int buf_prev_row_idx, buf_row_idx;
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    uint8_t rule;
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    uint64_t pts;
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    AVRational time_base;
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    char *rate;                 ///< video frame rate
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    double   random_fill_ratio;
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    uint32_t random_seed;
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    int stitch, scroll, start_full;
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    int64_t generation;         ///< the generation number, starting from 0
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    AVLFG lfg;
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    char *pattern;
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} CellAutoContext;
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#define OFFSET(x) offsetof(CellAutoContext, x)
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#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
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static const AVOption cellauto_options[] = {
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    { "filename", "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
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    { "f",        "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
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    { "pattern",  "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
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    { "p",        "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
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    { "rate",     "set video rate", OFFSET(rate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, FLAGS },
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    { "r",        "set video rate", OFFSET(rate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, FLAGS },
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    { "size",     "set video size", OFFSET(w),    AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
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    { "s",        "set video size", OFFSET(w),    AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
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    { "rule",     "set rule",       OFFSET(rule), AV_OPT_TYPE_INT,    {.i64 = 110},  0, 255, FLAGS },
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    { "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 },
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    { "ratio",             "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl = 1/M_PHI}, 0, 1, FLAGS },
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    { "random_seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
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    { "seed",        "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
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    { "scroll",      "scroll pattern downward", OFFSET(scroll), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, FLAGS },
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    { "start_full",  "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, FLAGS },
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    { "full",        "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, FLAGS },
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    { "stitch",      "stitch boundaries", OFFSET(stitch), AV_OPT_TYPE_INT,    {.i64 = 1},   0, 1, FLAGS },
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    { NULL },
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};
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AVFILTER_DEFINE_CLASS(cellauto);
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#ifdef DEBUG
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static void show_cellauto_row(AVFilterContext *ctx)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    int i;
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    uint8_t *row = cellauto->buf + cellauto->w * cellauto->buf_row_idx;
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    char *line = av_malloc(cellauto->w + 1);
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    if (!line)
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        return;
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    for (i = 0; i < cellauto->w; i++)
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        line[i] = row[i] ? '@' : ' ';
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    line[i] = 0;
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    av_log(ctx, AV_LOG_DEBUG, "generation:%"PRId64" row:%s|\n", cellauto->generation, line);
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    av_free(line);
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}
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#endif
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static int init_pattern_from_string(AVFilterContext *ctx)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    char *p;
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    int i, w = 0;
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    w = strlen(cellauto->pattern);
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    av_log(ctx, AV_LOG_DEBUG, "w:%d\n", w);
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    if (cellauto->w) {
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        if (w > cellauto->w) {
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            av_log(ctx, AV_LOG_ERROR,
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                   "The specified width is %d which cannot contain the provided string width of %d\n",
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                   cellauto->w, w);
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            return AVERROR(EINVAL);
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        }
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    } else {
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        /* width was not specified, set it to width of the provided row */
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        cellauto->w = w;
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        cellauto->h = (double)cellauto->w * M_PHI;
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    }
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    cellauto->buf = av_mallocz(sizeof(uint8_t) * cellauto->w * cellauto->h);
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    if (!cellauto->buf)
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        return AVERROR(ENOMEM);
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    /* fill buf */
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    p = cellauto->pattern;
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    for (i = (cellauto->w - w)/2;; i++) {
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        av_log(ctx, AV_LOG_DEBUG, "%d %c\n", i, *p == '\n' ? 'N' : *p);
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        if (*p == '\n' || !*p)
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            break;
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        else
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            cellauto->buf[i] = !!isgraph(*(p++));
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    }
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    return 0;
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}
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static int init_pattern_from_file(AVFilterContext *ctx)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    int ret;
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    ret = av_file_map(cellauto->filename,
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                      &cellauto->file_buf, &cellauto->file_bufsize, 0, ctx);
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    if (ret < 0)
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        return ret;
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    /* create a string based on the read file */
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    cellauto->pattern = av_malloc(cellauto->file_bufsize + 1);
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    if (!cellauto->pattern)
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        return AVERROR(ENOMEM);
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    memcpy(cellauto->pattern, cellauto->file_buf, cellauto->file_bufsize);
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    cellauto->pattern[cellauto->file_bufsize] = 0;
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    return init_pattern_from_string(ctx);
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}
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static int init(AVFilterContext *ctx, const char *args)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    AVRational frame_rate;
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    int ret;
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    cellauto->class = &cellauto_class;
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    av_opt_set_defaults(cellauto);
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    if ((ret = av_set_options_string(cellauto, args, "=", ":")) < 0)
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        return ret;
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    if ((ret = av_parse_video_rate(&frame_rate, cellauto->rate)) < 0) {
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        av_log(ctx, AV_LOG_ERROR, "Invalid frame rate: %s\n", cellauto->rate);
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        return AVERROR(EINVAL);
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    }
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    if (!cellauto->w && !cellauto->filename && !cellauto->pattern)
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        av_opt_set(cellauto, "size", "320x518", 0);
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    cellauto->time_base.num = frame_rate.den;
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    cellauto->time_base.den = frame_rate.num;
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    if (cellauto->filename && cellauto->pattern) {
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        av_log(ctx, AV_LOG_ERROR, "Only one of the filename or pattern options can be used\n");
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        return AVERROR(EINVAL);
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    }
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    if (cellauto->filename) {
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        if ((ret = init_pattern_from_file(ctx)) < 0)
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            return ret;
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    } else if (cellauto->pattern) {
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        if ((ret = init_pattern_from_string(ctx)) < 0)
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            return ret;
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    } else {
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        /* fill the first row randomly */
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        int i;
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        cellauto->buf = av_mallocz(sizeof(uint8_t) * cellauto->w * cellauto->h);
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        if (!cellauto->buf)
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            return AVERROR(ENOMEM);
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        if (cellauto->random_seed == -1)
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            cellauto->random_seed = av_get_random_seed();
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        av_lfg_init(&cellauto->lfg, cellauto->random_seed);
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        for (i = 0; i < cellauto->w; i++) {
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            double r = (double)av_lfg_get(&cellauto->lfg) / UINT32_MAX;
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            if (r <= cellauto->random_fill_ratio)
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                cellauto->buf[i] = 1;
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        }
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    }
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    av_log(ctx, AV_LOG_VERBOSE,
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           "s:%dx%d r:%d/%d rule:%d stitch:%d scroll:%d full:%d seed:%u\n",
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           cellauto->w, cellauto->h, frame_rate.num, frame_rate.den,
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           cellauto->rule, cellauto->stitch, cellauto->scroll, cellauto->start_full,
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           cellauto->random_seed);
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    return 0;
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    av_file_unmap(cellauto->file_buf, cellauto->file_bufsize);
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    av_freep(&cellauto->buf);
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    av_freep(&cellauto->pattern);
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}
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static int config_props(AVFilterLink *outlink)
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{
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    CellAutoContext *cellauto = outlink->src->priv;
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    outlink->w = cellauto->w;
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    outlink->h = cellauto->h;
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    outlink->time_base = cellauto->time_base;
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    return 0;
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}
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static void evolve(AVFilterContext *ctx)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    int i, v, pos[3];
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    uint8_t *row, *prev_row = cellauto->buf + cellauto->buf_row_idx * cellauto->w;
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    enum { NW, N, NE };
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    cellauto->buf_prev_row_idx = cellauto->buf_row_idx;
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    cellauto->buf_row_idx      = cellauto->buf_row_idx == cellauto->h-1 ? 0 : cellauto->buf_row_idx+1;
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    row = cellauto->buf + cellauto->w * cellauto->buf_row_idx;
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    for (i = 0; i < cellauto->w; i++) {
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        if (cellauto->stitch) {
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            pos[NW] = i-1 < 0 ? cellauto->w-1 : i-1;
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            pos[N]  = i;
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            pos[NE] = i+1 == cellauto->w ? 0  : i+1;
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            v = prev_row[pos[NW]]<<2 | prev_row[pos[N]]<<1 | prev_row[pos[NE]];
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        } else {
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            v = 0;
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            v|= i-1 >= 0          ? prev_row[i-1]<<2 : 0;
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            v|=                     prev_row[i  ]<<1    ;
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            v|= i+1 < cellauto->w ? prev_row[i+1]    : 0;
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        }
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        row[i] = !!(cellauto->rule & (1<<v));
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        av_dlog(ctx, "i:%d context:%c%c%c -> cell:%d\n", i,
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                v&4?'@':' ', v&2?'@':' ', v&1?'@':' ', row[i]);
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    }
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    cellauto->generation++;
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}
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static void fill_picture(AVFilterContext *ctx, AVFilterBufferRef *picref)
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{
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    CellAutoContext *cellauto = ctx->priv;
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    int i, j, k, row_idx = 0;
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    uint8_t *p0 = picref->data[0];
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    if (cellauto->scroll && cellauto->generation >= cellauto->h)
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        /* show on top the oldest row */
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        row_idx = (cellauto->buf_row_idx + 1) % cellauto->h;
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    /* fill the output picture with the whole buffer */
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    for (i = 0; i < cellauto->h; i++) {
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        uint8_t byte = 0;
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        uint8_t *row = cellauto->buf + row_idx*cellauto->w;
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        uint8_t *p = p0;
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        for (k = 0, j = 0; j < cellauto->w; j++) {
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            byte |= row[j]<<(7-k++);
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            if (k==8 || j == cellauto->w-1) {
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                k = 0;
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                *p++ = byte;
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                byte = 0;
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            }
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        }
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        row_idx = (row_idx + 1) % cellauto->h;
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        p0 += picref->linesize[0];
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    }
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}
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static int request_frame(AVFilterLink *outlink)
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{
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    CellAutoContext *cellauto = outlink->src->priv;
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    AVFilterBufferRef *picref =
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        ff_get_video_buffer(outlink, AV_PERM_WRITE, cellauto->w, cellauto->h);
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    picref->video->sample_aspect_ratio = (AVRational) {1, 1};
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    if (cellauto->generation == 0 && cellauto->start_full) {
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        int i;
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        for (i = 0; i < cellauto->h-1; i++)
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            evolve(outlink->src);
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    }
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    fill_picture(outlink->src, picref);
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    evolve(outlink->src);
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    picref->pts = cellauto->pts++;
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    picref->pos = -1;
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#ifdef DEBUG
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    show_cellauto_row(outlink->src);
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#endif
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    ff_filter_frame(outlink, picref);
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    return 0;
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}
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static int query_formats(AVFilterContext *ctx)
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{
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    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE };
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    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
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    return 0;
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}
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static const AVFilterPad cellauto_outputs[] = {
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    {
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        .name            = "default",
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        .type            = AVMEDIA_TYPE_VIDEO,
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        .request_frame   = request_frame,
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        .config_props    = config_props,
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    },
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    { NULL }
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};
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AVFilter avfilter_vsrc_cellauto = {
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    .name        = "cellauto",
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    .description = NULL_IF_CONFIG_SMALL("Create pattern generated by an elementary cellular automaton."),
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    .priv_size = sizeof(CellAutoContext),
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    .init      = init,
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    .uninit    = uninit,
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    .query_formats = query_formats,
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    .inputs        = NULL,
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    .outputs       = cellauto_outputs,
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    .priv_class    = &cellauto_class,
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};
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