FFmpeg
vsrc_sierpinski.c
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1 /*
2  * Copyright (c) 2019 Paul B Mahol
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  * Sierpinski carpet fractal renderer
24  */
25 
26 #include "avfilter.h"
27 #include "video.h"
28 #include "internal.h"
29 #include "libavutil/imgutils.h"
30 #include "libavutil/intreadwrite.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/lfg.h"
33 #include "libavutil/random_seed.h"
34 #include <float.h>
35 #include <math.h>
36 
37 typedef struct SierpinskiContext {
38  const AVClass *class;
39  int w, h;
40  int type;
42  uint64_t pts;
43 
44  int64_t seed;
45  int jump;
46 
47  int pos_x, pos_y;
48  int dest_x, dest_y;
49 
51  int (*draw_slice)(AVFilterContext *ctx, void *arg, int job, int nb_jobs);
53 
54 #define OFFSET(x) offsetof(SierpinskiContext, x)
55 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
56 
57 static const AVOption sierpinski_options[] = {
58  {"size", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
59  {"s", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
60  {"rate", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
61  {"r", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
62  {"seed", "set the seed", OFFSET(seed), AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT32_MAX, FLAGS },
63  {"jump", "set the jump", OFFSET(jump), AV_OPT_TYPE_INT, {.i64=100}, 1, 10000, FLAGS },
64  {"type","set fractal type",OFFSET(type), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "type" },
65  {"carpet", "sierpinski carpet", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "type" },
66  {"triangle", "sierpinski triangle", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "type" },
67  {NULL},
68 };
69 
70 AVFILTER_DEFINE_CLASS(sierpinski);
71 
72 static int fill_sierpinski(SierpinskiContext *s, int x, int y)
73 {
74  int pos_x = x + s->pos_x;
75  int pos_y = y + s->pos_y;
76 
77  while (pos_x != 0 && pos_y != 0) {
78  if (FFABS(pos_x % 3) == 1 && FFABS(pos_y % 3) == 1)
79  return 1;
80 
81  pos_x /= 3;
82  pos_y /= 3;
83  }
84 
85  return 0;
86 }
87 
88 static int draw_triangle_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
89 {
90  SierpinskiContext *s = ctx->priv;
91  AVFrame *frame = arg;
92  const int width = frame->width;
93  const int height = frame->height;
94  const int start = (height * job ) / nb_jobs;
95  const int end = (height * (job+1)) / nb_jobs;
96  uint8_t *dst = frame->data[0] + start * frame->linesize[0];
97 
98  for (int y = start; y < end; y++) {
99  for (int x = 0; x < width; x++) {
100  if ((s->pos_x + x) & (s->pos_y + y)) {
101  AV_WL32(&dst[x*4], 0x00000000);
102  } else {
103  AV_WL32(&dst[x*4], 0xFFFFFFFF);
104  }
105  }
106 
107  dst += frame->linesize[0];
108  }
109 
110  return 0;
111 }
112 
113 static int draw_carpet_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
114 {
115  SierpinskiContext *s = ctx->priv;
116  AVFrame *frame = arg;
117  const int width = frame->width;
118  const int height = frame->height;
119  const int start = (height * job ) / nb_jobs;
120  const int end = (height * (job+1)) / nb_jobs;
121  uint8_t *dst = frame->data[0] + start * frame->linesize[0];
122 
123  for (int y = start; y < end; y++) {
124  for (int x = 0; x < width; x++) {
125  if (fill_sierpinski(s, x, y)) {
126  AV_WL32(&dst[x*4], 0x00000000);
127  } else {
128  AV_WL32(&dst[x*4], 0xFFFFFFFF);
129  }
130  }
131 
132  dst += frame->linesize[0];
133  }
134 
135  return 0;
136 }
137 
138 static int config_output(AVFilterLink *outlink)
139 {
140  AVFilterContext *ctx = outlink->src;
141  SierpinskiContext *s = ctx->priv;
142 
143  if (av_image_check_size(s->w, s->h, 0, ctx) < 0)
144  return AVERROR(EINVAL);
145 
146  outlink->w = s->w;
147  outlink->h = s->h;
148  outlink->time_base = av_inv_q(s->frame_rate);
149  outlink->sample_aspect_ratio = (AVRational) {1, 1};
150  outlink->frame_rate = s->frame_rate;
151  if (s->seed == -1)
152  s->seed = av_get_random_seed();
153  av_lfg_init(&s->lfg, s->seed);
154 
155  s->draw_slice = s->type ? draw_triangle_slice : draw_carpet_slice;
156 
157  return 0;
158 }
159 
161 {
162  SierpinskiContext *s = ctx->priv;
163  AVFilterLink *outlink = ctx->outputs[0];
164 
165  if (s->pos_x == s->dest_x && s->pos_y == s->dest_y) {
166  unsigned int rnd = av_lfg_get(&s->lfg);
167  int mod = 2 * s->jump + 1;
168 
169  s->dest_x += (int)((rnd & 0xffff) % mod) - s->jump;
170  s->dest_y += (int)((rnd >> 16) % mod) - s->jump;
171  } else {
172  if (s->pos_x < s->dest_x)
173  s->pos_x++;
174  else if (s->pos_x > s->dest_x)
175  s->pos_x--;
176 
177  if (s->pos_y < s->dest_y)
178  s->pos_y++;
179  else if (s->pos_y > s->dest_y)
180  s->pos_y--;
181  }
182 
183  ff_filter_execute(ctx, s->draw_slice, frame, NULL,
184  FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
185 }
186 
188 {
189  SierpinskiContext *s = link->src->priv;
190  AVFrame *frame = ff_get_video_buffer(link, s->w, s->h);
191 
192  if (!frame)
193  return AVERROR(ENOMEM);
194 
195  frame->sample_aspect_ratio = (AVRational) {1, 1};
196  frame->pts = s->pts++;
197  frame->duration = 1;
198 
199  draw_sierpinski(link->src, frame);
200 
201  return ff_filter_frame(link, frame);
202 }
203 
204 static const AVFilterPad sierpinski_outputs[] = {
205  {
206  .name = "default",
207  .type = AVMEDIA_TYPE_VIDEO,
208  .request_frame = sierpinski_request_frame,
209  .config_props = config_output,
210  },
211 };
212 
214  .name = "sierpinski",
215  .description = NULL_IF_CONFIG_SMALL("Render a Sierpinski fractal."),
216  .priv_size = sizeof(SierpinskiContext),
217  .priv_class = &sierpinski_class,
218  .inputs = NULL,
222 };
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(sierpinski)
ff_get_video_buffer
AVFrame * ff_get_video_buffer(AVFilterLink *link, int w, int h)
Request a picture buffer with a specific set of permissions.
Definition: video.c:108
SierpinskiContext::jump
int jump
Definition: vsrc_sierpinski.c:45
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
AV_WL32
#define AV_WL32(p, v)
Definition: intreadwrite.h:424
SierpinskiContext::pts
uint64_t pts
Definition: vsrc_sierpinski.c:42
av_lfg_init
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:32
sierpinski_options
static const AVOption sierpinski_options[]
Definition: vsrc_sierpinski.c:57
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:978
AV_OPT_TYPE_VIDEO_RATE
@ AV_OPT_TYPE_VIDEO_RATE
offset must point to AVRational
Definition: opt.h:238
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:340
w
uint8_t w
Definition: llviddspenc.c:38
AVOption
AVOption.
Definition: opt.h:251
float.h
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:170
video.h
av_get_random_seed
uint32_t av_get_random_seed(void)
Get a seed to use in conjunction with random functions.
Definition: random_seed.c:167
config_output
static int config_output(AVFilterLink *outlink)
Definition: vsrc_sierpinski.c:138
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:47
rnd
#define rnd()
Definition: checkasm.h:122
draw_carpet_slice
static int draw_carpet_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
Definition: vsrc_sierpinski.c:113
width
#define width
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
av_lfg_get
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:53
AV_PIX_FMT_0BGR32
#define AV_PIX_FMT_0BGR32
Definition: pixfmt.h:446
lfg.h
AV_OPT_TYPE_INT64
@ AV_OPT_TYPE_INT64
Definition: opt.h:226
ctx
AVFormatContext * ctx
Definition: movenc.c:48
FLAGS
#define FLAGS
Definition: vsrc_sierpinski.c:55
link
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a link
Definition: filter_design.txt:23
arg
const char * arg
Definition: jacosubdec.c:67
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:65
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AV_OPT_TYPE_IMAGE_SIZE
@ AV_OPT_TYPE_IMAGE_SIZE
offset must point to two consecutive integers
Definition: opt.h:235
SierpinskiContext::pos_y
int pos_y
Definition: vsrc_sierpinski.c:47
ff_vsrc_sierpinski
const AVFilter ff_vsrc_sierpinski
Definition: vsrc_sierpinski.c:213
draw_sierpinski
static void draw_sierpinski(AVFilterContext *ctx, AVFrame *frame)
Definition: vsrc_sierpinski.c:160
inputs
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
Definition: filter_design.txt:243
seed
static unsigned int seed
Definition: videogen.c:78
SierpinskiContext::dest_y
int dest_y
Definition: vsrc_sierpinski.c:48
SierpinskiContext::dest_x
int dest_x
Definition: vsrc_sierpinski.c:48
SierpinskiContext::type
int type
Definition: vsrc_sierpinski.c:40
AVLFG
Context structure for the Lagged Fibonacci PRNG.
Definition: lfg.h:33
SierpinskiContext::h
int h
Definition: vsrc_sierpinski.c:39
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:106
sierpinski_outputs
static const AVFilterPad sierpinski_outputs[]
Definition: vsrc_sierpinski.c:204
height
#define height
SierpinskiContext::draw_slice
int(* draw_slice)(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
Definition: vsrc_sierpinski.c:51
internal.h
FILTER_SINGLE_PIXFMT
#define FILTER_SINGLE_PIXFMT(pix_fmt_)
Definition: internal.h:182
SierpinskiContext::pos_x
int pos_x
Definition: vsrc_sierpinski.c:47
SierpinskiContext::w
int w
Definition: vsrc_sierpinski.c:39
SierpinskiContext::seed
int64_t seed
Definition: vsrc_sierpinski.c:44
ff_filter_get_nb_threads
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:786
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
av_inv_q
static av_always_inline AVRational av_inv_q(AVRational q)
Invert a rational.
Definition: rational.h:159
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:53
mod
static int mod(int a, int b)
Modulo operation with only positive remainders.
Definition: vf_v360.c:750
SierpinskiContext::frame_rate
AVRational frame_rate
Definition: vsrc_sierpinski.c:41
AVFilter
Filter definition.
Definition: avfilter.h:166
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
random_seed.h
draw_triangle_slice
static int draw_triangle_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
Definition: vsrc_sierpinski.c:88
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:225
avfilter.h
fill_sierpinski
static int fill_sierpinski(SierpinskiContext *s, int x, int y)
Definition: vsrc_sierpinski.c:72
AVFilterContext
An instance of a filter.
Definition: avfilter.h:397
AVFILTER_FLAG_SLICE_THREADS
#define AVFILTER_FLAG_SLICE_THREADS
The filter supports multithreading by splitting frames into multiple parts and processing them concur...
Definition: avfilter.h:117
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:193
SierpinskiContext::lfg
AVLFG lfg
Definition: vsrc_sierpinski.c:50
imgutils.h
av_image_check_size
int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of the image can be address...
Definition: imgutils.c:318
ff_filter_execute
static av_always_inline int ff_filter_execute(AVFilterContext *ctx, avfilter_action_func *func, void *arg, int *ret, int nb_jobs)
Definition: internal.h:144
int
int
Definition: ffmpeg_filter.c:331
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:234
sierpinski_request_frame
static int sierpinski_request_frame(AVFilterLink *link)
Definition: vsrc_sierpinski.c:187
SierpinskiContext
Definition: vsrc_sierpinski.c:37
OFFSET
#define OFFSET(x)
Definition: vsrc_sierpinski.c:54