FFmpeg
vsrc_gradients.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2020 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 #include "avfilter.h"
22 #include "filters.h"
23 #include "formats.h"
24 #include "video.h"
25 #include "internal.h"
26 #include "libavutil/imgutils.h"
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/opt.h"
29 #include "libavutil/parseutils.h"
30 #include "libavutil/lfg.h"
31 #include "libavutil/random_seed.h"
32 #include <float.h>
33 #include <math.h>
34 
35 typedef struct GradientsContext {
36  const AVClass *class;
37  int w, h;
38  int type;
40  int64_t pts;
41  int64_t duration; ///< duration expressed in microseconds
42  float speed;
43 
44  uint8_t color_rgba[8][4];
45  int nb_colors;
46  int x0, y0, x1, y1;
47  float fx0, fy0, fx1, fy1;
48 
49  int64_t seed;
50 
52  int (*draw_slice)(AVFilterContext *ctx, void *arg, int job, int nb_jobs);
54 
55 #define OFFSET(x) offsetof(GradientsContext, x)
56 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
57 
58 static const AVOption gradients_options[] = {
59  {"size", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
60  {"s", "set frame size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="640x480"}, 0, 0, FLAGS },
61  {"rate", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
62  {"r", "set frame rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
63  {"c0", "set 1st color", OFFSET(color_rgba[0]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
64  {"c1", "set 2nd color", OFFSET(color_rgba[1]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
65  {"c2", "set 3rd color", OFFSET(color_rgba[2]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
66  {"c3", "set 4th color", OFFSET(color_rgba[3]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
67  {"c4", "set 5th color", OFFSET(color_rgba[4]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
68  {"c5", "set 6th color", OFFSET(color_rgba[5]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
69  {"c6", "set 7th color", OFFSET(color_rgba[6]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
70  {"c7", "set 8th color", OFFSET(color_rgba[7]), AV_OPT_TYPE_COLOR, {.str = "random"}, 0, 0, FLAGS },
71  {"x0", "set gradient line source x0", OFFSET(x0), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
72  {"y0", "set gradient line source y0", OFFSET(y0), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
73  {"x1", "set gradient line destination x1", OFFSET(x1), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
74  {"y1", "set gradient line destination y1", OFFSET(y1), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
75  {"nb_colors", "set the number of colors", OFFSET(nb_colors), AV_OPT_TYPE_INT, {.i64=2}, 2, 8, FLAGS },
76  {"n", "set the number of colors", OFFSET(nb_colors), AV_OPT_TYPE_INT, {.i64=2}, 2, 8, FLAGS },
77  {"seed", "set the seed", OFFSET(seed), AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT32_MAX, FLAGS },
78  {"duration", "set video duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64=-1}, -1, INT64_MAX, FLAGS },\
79  {"d", "set video duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64=-1}, -1, INT64_MAX, FLAGS },\
80  {"speed", "set gradients rotation speed", OFFSET(speed), AV_OPT_TYPE_FLOAT,{.dbl=0.01}, 0.00001, 1, FLAGS },\
81  {NULL},
82 };
83 
84 AVFILTER_DEFINE_CLASS(gradients);
85 
87 {
88  static const enum AVPixelFormat pix_fmts[] = {
92  };
93 
95  if (!fmts_list)
96  return AVERROR(ENOMEM);
97  return ff_set_common_formats(ctx, fmts_list);
98 }
99 
100 static uint32_t lerp_color(uint8_t c0[4], uint8_t c1[4], float x)
101 {
102  const float y = 1.f - x;
103 
104  return (lrintf(c0[0] * y + c1[0] * x)) << 0 |
105  (lrintf(c0[1] * y + c1[1] * x)) << 8 |
106  (lrintf(c0[2] * y + c1[2] * x)) << 16 |
107  (lrintf(c0[3] * y + c1[3] * x)) << 24;
108 }
109 
110 static uint64_t lerp_color16(uint8_t c0[4], uint8_t c1[4], float x)
111 {
112  const float y = 1.f - x;
113 
114  return (llrintf((c0[0] * y + c1[0] * x) * 256)) << 0 |
115  (llrintf((c0[1] * y + c1[1] * x) * 256)) << 16 |
116  (llrintf((c0[2] * y + c1[2] * x) * 256)) << 32 |
117  (llrintf((c0[3] * y + c1[3] * x) * 256)) << 48;
118 }
119 
120 static uint32_t lerp_colors(uint8_t arr[3][4], int nb_colors, float step)
121 {
122  float scl;
123  int i;
124 
125  if (nb_colors == 1 || step <= 0.0) {
126  return arr[0][0] | (arr[0][1] << 8) | (arr[0][2] << 16) | (arr[0][3] << 24);
127  } else if (step >= 1.0) {
128  i = nb_colors - 1;
129  return arr[i][0] | (arr[i][1] << 8) | (arr[i][2] << 16) | (arr[i][3] << 24);
130  }
131 
132  scl = step * (nb_colors - 1);
133  i = floorf(scl);
134 
135  return lerp_color(arr[i], arr[i + 1], scl - i);
136 }
137 
138 static uint64_t lerp_colors16(uint8_t arr[3][4], int nb_colors, float step)
139 {
140  float scl;
141  int i;
142 
143  if (nb_colors == 1 || step <= 0.0) {
144  return ((uint64_t)arr[0][0] << 8) | ((uint64_t)arr[0][1] << 24) | ((uint64_t)arr[0][2] << 40) | ((uint64_t)arr[0][3] << 56);
145  } else if (step >= 1.0) {
146  i = nb_colors - 1;
147  return ((uint64_t)arr[i][0] << 8) | ((uint64_t)arr[i][1] << 24) | ((uint64_t)arr[i][2] << 40) | ((uint64_t)arr[i][3] << 56);
148  }
149 
150  scl = step * (nb_colors - 1);
151  i = floorf(scl);
152 
153  return lerp_color16(arr[i], arr[i + 1], scl - i);
154 }
155 
156 static float project(float origin_x, float origin_y,
157  float dest_x, float dest_y,
158  int point_x, int point_y)
159 {
160  // Rise and run of line.
161  float od_x = dest_x - origin_x;
162  float od_y = dest_y - origin_y;
163 
164  // Distance-squared of line.
165  float od_s_q = od_x * od_x + od_y * od_y;
166 
167  // Rise and run of projection.
168  float op_x = point_x - origin_x;
169  float op_y = point_y - origin_y;
170  float op_x_od = op_x * od_x + op_y * od_y;
171 
172  // Normalize and clamp range.
173  return av_clipf(op_x_od / od_s_q, 0.f, 1.f);
174 }
175 
176 static int draw_gradients_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
177 {
178  GradientsContext *s = ctx->priv;
179  AVFrame *frame = arg;
180  const int width = frame->width;
181  const int height = frame->height;
182  const int start = (height * job ) / nb_jobs;
183  const int end = (height * (job+1)) / nb_jobs;
184  const int linesize = frame->linesize[0] / 4;
185  uint32_t *dst = (uint32_t *)frame->data[0] + start * linesize;
186 
187  for (int y = start; y < end; y++) {
188  for (int x = 0; x < width; x++) {
189  float factor = project(s->fx0, s->fy0, s->fx1, s->fy1, x, y);
190  dst[x] = lerp_colors(s->color_rgba, s->nb_colors, factor);
191  }
192 
193  dst += linesize;
194  }
195 
196  return 0;
197 }
198 
199 static int draw_gradients_slice16(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
200 {
201  GradientsContext *s = ctx->priv;
202  AVFrame *frame = arg;
203  const int width = frame->width;
204  const int height = frame->height;
205  const int start = (height * job ) / nb_jobs;
206  const int end = (height * (job+1)) / nb_jobs;
207  const int linesize = frame->linesize[0] / 8;
208  uint64_t *dst = (uint64_t *)frame->data[0] + start * linesize;
209 
210  for (int y = start; y < end; y++) {
211  for (int x = 0; x < width; x++) {
212  float factor = project(s->fx0, s->fy0, s->fx1, s->fy1, x, y);
213  dst[x] = lerp_colors16(s->color_rgba, s->nb_colors, factor);
214  }
215 
216  dst += linesize;
217  }
218 
219  return 0;
221 {
222  AVFilterContext *ctx = inlink->src;
223  GradientsContext *s = ctx->priv;
225 
226  if (av_image_check_size(s->w, s->h, 0, ctx) < 0)
227  return AVERROR(EINVAL);
228 
229  inlink->w = s->w;
230  inlink->h = s->h;
231  inlink->time_base = av_inv_q(s->frame_rate);
232  inlink->sample_aspect_ratio = (AVRational) {1, 1};
233  if (s->seed == -1)
234  s->seed = av_get_random_seed();
235  av_lfg_init(&s->lfg, s->seed);
236 
237  s->draw_slice = desc->comp[0].depth == 16 ? draw_gradients_slice16 : draw_gradients_slice;
238 
239  if (s->x0 < 0 || s->x0 >= s->w)
240  s->x0 = av_lfg_get(&s->lfg) % s->w;
241  if (s->y0 < 0 || s->y0 >= s->h)
242  s->y0 = av_lfg_get(&s->lfg) % s->h;
243  if (s->x1 < 0 || s->x1 >= s->w)
244  s->x1 = av_lfg_get(&s->lfg) % s->w;
245  if (s->y1 < 0 || s->y1 >= s->h)
246  s->y1 = av_lfg_get(&s->lfg) % s->h;
247 
248  return 0;
249 }
250 
252 {
253  GradientsContext *s = ctx->priv;
254  AVFilterLink *outlink = ctx->outputs[0];
255 
256  if (s->duration >= 0 &&
257  av_rescale_q(s->pts, outlink->time_base, AV_TIME_BASE_Q) >= s->duration) {
258  ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
259  return 0;
260  }
261 
262  if (ff_outlink_frame_wanted(outlink)) {
263  AVFrame *frame = ff_get_video_buffer(outlink, s->w, s->h);
264  float angle = fmodf(s->pts * s->speed, 2.f * M_PI);
265  const float w2 = s->w / 2.f;
266  const float h2 = s->h / 2.f;
267 
268  s->fx0 = (s->x0 - w2) * cosf(angle) - (s->y0 - h2) * sinf(angle) + w2;
269  s->fy0 = (s->x0 - w2) * sinf(angle) + (s->y0 - h2) * cosf(angle) + h2;
270 
271  s->fx1 = (s->x1 - w2) * cosf(angle) - (s->y1 - h2) * sinf(angle) + w2;
272  s->fy1 = (s->x1 - w2) * sinf(angle) + (s->y1 - h2) * cosf(angle) + h2;
273 
274  if (!frame)
275  return AVERROR(ENOMEM);
276 
277  frame->key_frame = 1;
278  frame->interlaced_frame = 0;
279  frame->pict_type = AV_PICTURE_TYPE_I;
280  frame->sample_aspect_ratio = (AVRational) {1, 1};
281  frame->pts = s->pts++;
282 
283  ctx->internal->execute(ctx, s->draw_slice, frame, NULL,
284  FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
285 
286  return ff_filter_frame(outlink, frame);
287  }
288 
289  return FFERROR_NOT_READY;
290 }
291 
292 static const AVFilterPad gradients_outputs[] = {
293  {
294  .name = "default",
295  .type = AVMEDIA_TYPE_VIDEO,
296  .config_props = config_output,
297  },
298  { NULL }
299 };
300 
302  .name = "gradients",
303  .description = NULL_IF_CONFIG_SMALL("Draw a gradients."),
304  .priv_size = sizeof(GradientsContext),
305  .priv_class = &gradients_class,
307  .inputs = NULL,
309  .activate = activate,
311 };
GradientsContext::nb_colors
int nb_colors
Definition: vsrc_gradients.c:45
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:97
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
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
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: vsrc_gradients.c:86
ff_make_format_list
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:286
GradientsContext::pts
int64_t pts
Definition: vsrc_gradients.c:40
av_lfg_init
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:32
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:978
ff_vsrc_gradients
const AVFilter ff_vsrc_gradients
Definition: vsrc_gradients.c:301
av_pix_fmt_desc_get
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2540
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
FFERROR_NOT_READY
return FFERROR_NOT_READY
Definition: filter_design.txt:204
AV_OPT_TYPE_VIDEO_RATE
@ AV_OPT_TYPE_VIDEO_RATE
offset must point to AVRational
Definition: opt.h:237
floorf
static __device__ float floorf(float a)
Definition: cuda_runtime.h:172
AV_TIME_BASE_Q
#define AV_TIME_BASE_Q
Internal time base represented as fractional value.
Definition: avutil.h:260
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
step
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But a word about which is also called distortion Distortion can be quantified by almost any quality measurement one chooses the sum of squared differences is used but more complex methods that consider psychovisual effects can be used as well It makes no difference in this discussion First step
Definition: rate_distortion.txt:58
w
uint8_t w
Definition: llviddspenc.c:38
AVOption
AVOption.
Definition: opt.h:247
GradientsContext::lfg
AVLFG lfg
Definition: vsrc_gradients.c:51
AV_OPT_TYPE_DURATION
@ AV_OPT_TYPE_DURATION
Definition: opt.h:238
float.h
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:149
c1
static const uint64_t c1
Definition: murmur3.c:51
video.h
AVFormatContext::internal
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1565
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:120
AVFilterFormats
A list of supported formats for one end of a filter link.
Definition: formats.h:64
formats.h
cosf
#define cosf(x)
Definition: libm.h:78
lerp_colors
static uint32_t lerp_colors(uint8_t arr[3][4], int nb_colors, float step)
Definition: vsrc_gradients.c:120
config_output
static int config_output(AVFilterLink *inlink)
Definition: vsrc_gradients.c:220
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:54
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
ff_set_common_formats
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:580
GradientsContext::y0
int y0
Definition: vsrc_gradients.c:46
duration
int64_t duration
Definition: movenc.c:64
GradientsContext::fy0
float fy0
Definition: vsrc_gradients.c:47
ff_outlink_set_status
static void ff_outlink_set_status(AVFilterLink *link, int status, int64_t pts)
Set the status field of a link from the source filter.
Definition: filters.h:189
width
#define width
llrintf
#define llrintf(x)
Definition: libm.h:399
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
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
lfg.h
AV_OPT_TYPE_INT64
@ AV_OPT_TYPE_INT64
Definition: opt.h:225
outputs
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
filters.h
pix_fmts
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:290
gradients_options
static const AVOption gradients_options[]
Definition: vsrc_gradients.c:58
ctx
AVFormatContext * ctx
Definition: movenc.c:48
av_rescale_q
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:141
f
#define f(width, name)
Definition: cbs_vp9.c:255
lerp_colors16
static uint64_t lerp_colors16(uint8_t arr[3][4], int nb_colors, float step)
Definition: vsrc_gradients.c:138
AV_PIX_FMT_RGBA
@ AV_PIX_FMT_RGBA
packed RGBA 8:8:8:8, 32bpp, RGBARGBA...
Definition: pixfmt.h:93
arg
const char * arg
Definition: jacosubdec.c:67
AV_PIX_FMT_RGBA64
#define AV_PIX_FMT_RGBA64
Definition: pixfmt.h:379
GradientsContext::seed
int64_t seed
Definition: vsrc_gradients.c:49
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
OFFSET
#define OFFSET(x)
Definition: vsrc_gradients.c:55
NULL
#define NULL
Definition: coverity.c:32
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
gradients_outputs
static const AVFilterPad gradients_outputs[]
Definition: vsrc_gradients.c:292
AV_OPT_TYPE_COLOR
@ AV_OPT_TYPE_COLOR
Definition: opt.h:239
AV_OPT_TYPE_IMAGE_SIZE
@ AV_OPT_TYPE_IMAGE_SIZE
offset must point to two consecutive integers
Definition: opt.h:234
av_clipf
#define av_clipf
Definition: common.h:170
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
parseutils.h
GradientsContext::duration
int64_t duration
duration expressed in microseconds
Definition: vsrc_gradients.c:41
GradientsContext::y1
int y1
Definition: vsrc_gradients.c:46
sinf
#define sinf(x)
Definition: libm.h:419
seed
static unsigned int seed
Definition: videogen.c:78
for
for(j=16;j >0;--j)
Definition: h264pred_template.c:469
GradientsContext::fx0
float fx0
Definition: vsrc_gradients.c:47
GradientsContext::w
int w
Definition: vsrc_gradients.c:37
AVLFG
Context structure for the Lagged Fibonacci PRNG.
Definition: lfg.h:33
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:116
FLAGS
#define FLAGS
Definition: vsrc_gradients.c:56
GradientsContext::h
int h
Definition: vsrc_gradients.c:37
GradientsContext::x0
int x0
Definition: vsrc_gradients.c:46
GradientsContext::speed
float speed
Definition: vsrc_gradients.c:42
GradientsContext::x1
int x1
Definition: vsrc_gradients.c:46
height
#define height
FFMIN
#define FFMIN(a, b)
Definition: common.h:105
draw_gradients_slice
static int draw_gradients_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
Definition: vsrc_gradients.c:176
GradientsContext::fx1
float fx1
Definition: vsrc_gradients.c:47
M_PI
#define M_PI
Definition: mathematics.h:52
internal.h
AV_OPT_TYPE_FLOAT
@ AV_OPT_TYPE_FLOAT
Definition: opt.h:227
i
int i
Definition: input.c:406
lrintf
#define lrintf(x)
Definition: libm_mips.h:72
GradientsContext
Definition: vsrc_gradients.c:35
ff_filter_get_nb_threads
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:762
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:60
AVFilter
Filter definition.
Definition: avfilter.h:145
GradientsContext::fy1
float fy1
Definition: vsrc_gradients.c:47
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
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(gradients)
random_seed.h
GradientsContext::type
int type
Definition: vsrc_gradients.c:38
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
lerp_color16
static uint64_t lerp_color16(uint8_t c0[4], uint8_t c1[4], float x)
Definition: vsrc_gradients.c:110
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:224
avfilter.h
AVFilterContext
An instance of a filter.
Definition: avfilter.h:333
factor
static const int factor[16]
Definition: vf_pp7.c:76
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
desc
const char * desc
Definition: libsvtav1.c:79
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
GradientsContext::draw_slice
int(* draw_slice)(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
Definition: vsrc_gradients.c:52
GradientsContext::color_rgba
uint8_t color_rgba[8][4]
Definition: vsrc_gradients.c:44
AVPixFmtDescriptor
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:69
activate
static int activate(AVFilterContext *ctx)
Definition: vsrc_gradients.c:251
GradientsContext::frame_rate
AVRational frame_rate
Definition: vsrc_gradients.c:39
imgutils.h
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
ff_outlink_frame_wanted
the definition of that something depends on the semantic of the filter The callback must examine the status of the filter s links and proceed accordingly The status of output links is stored in the status_in and status_out fields and tested by the ff_outlink_frame_wanted() function. If this function returns true
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
project
static float project(float origin_x, float origin_y, float dest_x, float dest_y, int point_x, int point_y)
Definition: vsrc_gradients.c:156
int
int
Definition: ffmpeg_filter.c:156
lerp_color
static uint32_t lerp_color(uint8_t c0[4], uint8_t c1[4], float x)
Definition: vsrc_gradients.c:100
draw_gradients_slice16
static int draw_gradients_slice16(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
Definition: vsrc_gradients.c:199