avfilter: add sierpinski video source

1 files changed, 203 insertions, 0 deletions

diff --git a/libavfilter/vsrc_sierpinski.c b/libavfilter/vsrc_sierpinski.c
new file mode 100644
index 0000000000..49867d7470
--- /dev/null
+++ b/libavfilter/vsrc_sierpinski.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2019 Paul B Mahol
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Sierpinski carpet fractal renderer
+ */
+
+#include "avfilter.h"
+#include "formats.h"
+#include "video.h"
+#include "internal.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "libavutil/lfg.h"
+#include "libavutil/random_seed.h"
+#include <float.h>
+#include <math.h>
+
+typedef struct SierpinskiContext {
+    const AVClass *class;
+    int w, h;
+    AVRational frame_rate;
+    uint64_t pts;
+
+    unsigned int seed;
+    int jump;
+
+    int pos_x, pos_y;
+    int dest_x, dest_y;
+
+    AVLFG lfg;
+} SierpinskiContext;
+
+#define OFFSET(x) offsetof(SierpinskiContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption sierpinski_options[] = {
+    {"size", "set frame size", OFFSET(w),          AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0,          0, FLAGS },
+    {"s",    "set frame size", OFFSET(w),          AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0,          0, FLAGS },
+    {"rate", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"},      0,          0, FLAGS },
+    {"r",    "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"},      0,          0, FLAGS },
+    {"seed", "set the seed",   OFFSET(seed),       AV_OPT_TYPE_INT,        {.i64=-1},       -1, UINT32_MAX, FLAGS },
+    {"jump", "set the jump",   OFFSET(jump),       AV_OPT_TYPE_INT,        {.i64=100},       1,      10000, FLAGS },
+    {NULL},
+};
+
+AVFILTER_DEFINE_CLASS(sierpinski);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_0BGR32,
+        AV_PIX_FMT_NONE
+    };
+
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+static int config_output(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->src;
+    SierpinskiContext *s = ctx->priv;
+
+    if (av_image_check_size(s->w, s->h, 0, ctx) < 0)
+        return AVERROR(EINVAL);
+
+    inlink->w = s->w;
+    inlink->h = s->h;
+    inlink->time_base = av_inv_q(s->frame_rate);
+    inlink->sample_aspect_ratio = (AVRational) {1, 1};
+    if (s->seed == -1)
+        s->seed = av_get_random_seed();
+    av_lfg_init(&s->lfg, s->seed);
+
+    return 0;
+}
+
+static int fill_sierpinski(SierpinskiContext *s, int x, int y)
+{
+    int pos_x = x + s->pos_x;
+    int pos_y = y + s->pos_y;
+
+    while (pos_x != 0 && pos_y != 0) {
+        if (FFABS(pos_x % 3) == 1 && FFABS(pos_y % 3) == 1)
+            return 1;
+
+        pos_x /= 3;
+        pos_y /= 3;
+    }
+
+    return 0;
+}
+
+static int draw_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
+{
+    SierpinskiContext *s = ctx->priv;
+    AVFrame *frame = arg;
+    const int width  = frame->width;
+    const int height = frame->height;
+    const int start = (height *  job   ) / nb_jobs;
+    const int end   = (height * (job+1)) / nb_jobs;
+    uint8_t *dst = frame->data[0] + start * frame->linesize[0];
+
+    for (int y = start; y < end; y++) {
+        for (int x = 0; x < width; x++) {
+            if (fill_sierpinski(s, x, y)) {
+                AV_WL32(&dst[x*4], 0x00000000);
+            } else {
+                AV_WL32(&dst[x*4], 0xFFFFFFFF);
+            }
+        }
+
+        dst += frame->linesize[0];
+    }
+
+    return 0;
+}
+
+static void draw_sierpinski(AVFilterContext *ctx, AVFrame *frame)
+{
+    SierpinskiContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+
+    if (s->pos_x == s->dest_x && s->pos_y == s->dest_y) {
+        unsigned int rnd = av_lfg_get(&s->lfg);
+        int mod = 2 * s->jump + 1;
+
+        s->dest_x += (int)((rnd & 0xffff) % mod) - s->jump;
+        s->dest_y += (int)((rnd >>    16) % mod) - s->jump;
+    } else {
+        if (s->pos_x < s->dest_x)
+            s->pos_x++;
+        else if (s->pos_x > s->dest_x)
+            s->pos_x--;
+
+        if (s->pos_y < s->dest_y)
+            s->pos_y++;
+        else if (s->pos_y > s->dest_y)
+            s->pos_y--;
+    }
+
+    ctx->internal->execute(ctx, draw_slice, frame, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
+}
+
+static int sierpinski_request_frame(AVFilterLink *link)
+{
+    SierpinskiContext *s = link->src->priv;
+    AVFrame *frame = ff_get_video_buffer(link, s->w, s->h);
+
+    if (!frame)
+        return AVERROR(ENOMEM);
+
+    frame->sample_aspect_ratio = (AVRational) {1, 1};
+    frame->pts = s->pts++;
+
+    draw_sierpinski(link->src, frame);
+
+    return ff_filter_frame(link, frame);
+}
+
+static const AVFilterPad sierpinski_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = sierpinski_request_frame,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vsrc_sierpinski = {
+    .name          = "sierpinski",
+    .description   = NULL_IF_CONFIG_SMALL("Render a Sierpinski carpet fractal."),
+    .priv_size     = sizeof(SierpinskiContext),
+    .priv_class    = &sierpinski_class,
+    .query_formats = query_formats,
+    .inputs        = NULL,
+    .outputs       = sierpinski_outputs,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
+};