lavfi: add Perlin noise generator

Stefano Sabatini committed 2 years ago

Commit 3764b8e1 parent c9151ea7 files · +597 −0Browse files

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7 files

Changelog +1 −0
doc/filters.texi +100 −0
libavfilter/Makefile +1 −0
libavfilter/allfilters.c +1 −0
libavfilter/perlin.c +224 −0
libavfilter/perlin.h +101 −0
libavfilter/vsrc_perlin.c +169 −0

@@ -14,6 +14,7 @@ version <next>: · 13 unmodified lines
14	14	- xHE-AAC decoder
15	15	- removed DEC Alpha DSP and support code
16	16	- VVC encoding support via libvvenc
	17	+- perlin video source
17	18
18	19
19	20	version 7.0:

doc/filters.texi+100−0

@@ -17290,6 +17290,9 @@ The command accepts the same syntax of the corresponding option. · 17289 unmodified lines
17290	17290	If the specified expression is not valid, it is kept at its current
17291	17291	value.
17292	17292
	17293	+@anchor{lutrgb}
	17294	+@anchor{lutyuv}
	17295	+@anchor{lut}
17293	17296	@section lut, lutrgb, lutyuv
17294	17297
17295	17298	Compute a look-up table for binding each pixel component input value
@@ -29281,6 +29284,103 @@ ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_c · 11985 unmodified lines
29281	29284	@end example
29282	29285	@end itemize
29283	29286
	29287	+@section perlin
	29288	+Generate Perlin noise.
	29289	+
	29290	+Perlin noise is a kind of noise with local continuity in space. This
	29291	+can be used to generate patterns with continuity in space and time,
	29292	+e.g. to simulate smoke, fluids, or terrain.
	29293	+
	29294	+In case more than one octave is specified through the @option{octaves}
	29295	+option, Perlin noise is generated as a sum of components, each one
	29296	+with doubled frequency. In this case the @option{persistence} option
	29297	+specify the ratio of the amplitude with respect to the previous
	29298	+component. More octave components enable to specify more high
	29299	+frequency details in the generated noise (e.g. small size variations
	29300	+due to boulders in a generated terrain).
	29301	+
	29302	+@subsection Options
	29303	+@table @option
	29304	+
	29305	+@item size, s
	29306	+Specify the size (width and height) of the buffered video frames. For the
	29307	+syntax of this option, check the
	29308	+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
	29309	+
	29310	+@item rate, r
	29311	+Specify the frame rate expected for the video stream, expressed as a
	29312	+number of frames per second.
	29313	+
	29314	+@item octaves
	29315	+Specify the total number of components making up the noise, each one
	29316	+with doubled frequency.
	29317	+
	29318	+@item persistence
	29319	+Set the ratio used to compute the amplitude of the next octave
	29320	+component with respect to the previous component amplitude.
	29321	+
	29322	+@item xscale
	29323	+@item yscale
	29324	+Define a scale factor used to multiple the x, y coordinates. This can
	29325	+be useful to define an effect with a pattern stretched along the x or
	29326	+y axis.
	29327	+
	29328	+@item tscale
	29329	+Define a scale factor used to multiple the time coordinate. This can
	29330	+be useful to change the time variation speed.
	29331	+
	29332	+@item random_mode
	29333	+Set random mode used to compute initial pattern.
	29334	+
	29335	+Supported values are:
	29336	+@table @option
	29337	+@item random
	29338	+Compute and use random seed.
	29339	+
	29340	+@item ken
	29341	+Use the predefined initial pattern defined by Ken Perlin in the
	29342	+original article, can be useful to compare the output with other
	29343	+sources.
	29344	+
	29345	+@item seed
	29346	+Use the value specified by @option{random_seed} option.
	29347	+@end table
	29348	+
	29349	+@item random_seed, seed
	29350	+When @option{random_mode} is set to @var{random_seed}, use this value
	29351	+to compute the initial pattern.
	29352	+@end table
	29353	+
	29354	+@subsection Examples
	29355	+@itemize
	29356	+@item
	29357	+Generate single component:
	29358	+@example
	29359	+perlin
	29360	+@end example
	29361	+
	29362	+@item
	29363	+Use Perlin noise with 7 components, each one with a halved contribution
	29364	+to total amplitude:
	29365	+@example
	29366	+perlin=octaves=7:persistence=0.5
	29367	+@end example
	29368	+
	29369	+@item
	29370	+Chain Perlin noise with the @ref{lutyuv} to generate a black&white
	29371	+effect:
	29372	+@example
	29373	+perlin=octaves=3:tscale=0.3,lutyuv=y='if(lt(val\,128)\,255\,0)'
	29374	+@end example
	29375	+
	29376	+@item
	29377	+Stretch noise along the y axis, and convert gray level to red-only
	29378	+signal:
	29379	+@example
	29380	+perlin=octaves=7:tscale=0.4:yscale=0.3,lutrgb=r=val:b=0:g=0
	29381	+@end example
	29382	+@end itemize
	29383	+
29284	29384	@section qrencodesrc
29285	29385
29286	29386	Generate a QR code using the libqrencode library (see

libavfilter/Makefile+1−0

@@ -603,6 +603,7 @@ OBJS-$(CONFIG_NULLSRC_FILTER) += vsrc_testsrc.o · 602 unmodified lines
603	603	OBJS-$(CONFIG_OPENCLSRC_FILTER) += vf_program_opencl.o opencl.o
604	604	OBJS-$(CONFIG_PAL75BARS_FILTER) += vsrc_testsrc.o
605	605	OBJS-$(CONFIG_PAL100BARS_FILTER) += vsrc_testsrc.o
	606	+OBJS-$(CONFIG_PERLIN_FILTER) += vsrc_perlin.o perlin.o
606	607	OBJS-$(CONFIG_QRENCODE_FILTER) += qrencode.o textutils.o
607	608	OBJS-$(CONFIG_QRENCODESRC_FILTER) += qrencode.o textutils.o
608	609	OBJS-$(CONFIG_RGBTESTSRC_FILTER) += vsrc_testsrc.o

libavfilter/allfilters.c+1−0

@@ -569,6 +569,7 @@ extern const AVFilter ff_vsrc_openclsrc; · 568 unmodified lines
569	569	extern const AVFilter ff_vsrc_qrencodesrc;
570	570	extern const AVFilter ff_vsrc_pal75bars;
571	571	extern const AVFilter ff_vsrc_pal100bars;
	572	+extern const AVFilter ff_vsrc_perlin;
572	573	extern const AVFilter ff_vsrc_rgbtestsrc;
573	574	extern const AVFilter ff_vsrc_sierpinski;
574	575	extern const AVFilter ff_vsrc_smptebars;

libavfilter/perlin.c+224−0

@@ -0,0 +1,224 @@
	1	+/*
	2	+ * This file is part of FFmpeg.
	3	+ *
	4	+ * FFmpeg is free software; you can redistribute it and/or modify
	5	+ * it under the terms of the GNU General Public License as published by
	6	+ * the Free Software Foundation; either version 2 of the License, or
	7	+ * (at your option) any later version.
	8	+ *
	9	+ * FFmpeg is distributed in the hope that it will be useful,
	10	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	+ * GNU General Public License for more details.
	13	+ *
	14	+ * You should have received a copy of the GNU General Public License along
	15	+ * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
	16	+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	17	+ */
	18	+
	19	+/**
	20	+ * @file
	21	+ * Perlin Noise generator, based on code from:
	22	+ * https://adrianb.io/2014/08/09/perlinnoise.html
	23	+ *
	24	+ * Original article from Ken Perlin:
	25	+ * http://mrl.nyu.edu/~perlin/paper445.pdf
	26	+ */
	27	+
	28	+#include <math.h>
	29	+
	30	+#include "libavutil/lfg.h"
	31	+#include "libavutil/random_seed.h"
	32	+#include "perlin.h"
	33	+
	34	+static inline int inc(int num, int period)
	35	+{
	36	+ num++;
	37	+ if (period > 0)
	38	+ num %= period;
	39	+ return num;
	40	+}
	41	+
	42	+static inline double grad(int hash, double x, double y, double z)
	43	+{
	44	+ // Take the hashed value and take the first 4 bits of it (15 == 0b1111)
	45	+ int h = hash & 15;
	46	+ // If the most significant bit (MSB) of the hash is 0 then set u = x. Otherwise y.
	47	+ double u = h < 8 /* 0b1000 */ ? x : y;
	48	+ double v;
	49	+
	50	+ // In Ken Perlin's original implementation this was another
	51	+ // conditional operator (?:), then expanded for readability.
	52	+ if (h < 4 /* 0b0100 */)
	53	+ // If the first and second significant bits are 0 set v = y
	54	+ v = y;
	55	+ // If the first and second significant bits are 1 set v = x
	56	+ else if (h == 12 /* 0b1100 / \|\| h == 14 / 0b1110 */)
	57	+ v = x;
	58	+ else
	59	+ // If the first and second significant bits are not equal (0/1, 1/0) set v = z
	60	+ v = z;
	61	+
	62	+ // Use the last 2 bits to decide if u and v are positive or negative. Then return their addition.
	63	+ return ((h&1) == 0 ? u : -u)+((h&2) == 0 ? v : -v);
	64	+}
	65	+
	66	+static inline double fade(double t)
	67	+{
	68	+ // Fade function as defined by Ken Perlin. This eases coordinate values
	69	+ // so that they will "ease" towards integral values. This ends up smoothing
	70	+ // the final output.
	71	+ // use Horner method to compute: 6t^5 - 15t^4 + 10t^3
	72	+ return t * t * t * (t * (t * 6 - 15) + 10);
	73	+}
	74	+
	75	+static double lerp(double a, double b, double x)
	76	+{
	77	+ return a + x * (b - a);
	78	+}
	79	+
	80	+// Hash lookup table as defined by Ken Perlin. This is a randomly
	81	+// arranged array of all numbers from 0-255 inclusive.
	82	+static uint8_t ken_permutations[] = {
	83	+ 151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225,
	84	+ 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148,
	85	+ 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32,
	86	+ 57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175,
	87	+ 74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122,
	88	+ 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54,
	89	+ 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169,
	90	+ 200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64,
	91	+ 52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212,
	92	+ 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213,
	93	+ 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
	94	+ 129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104,
	95	+ 218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241,
	96	+ 81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,
	97	+ 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93,
	98	+ 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180
	99	+};
	100	+
	101	+int ff_perlin_init(FFPerlin *perlin, double period, int octaves, double persistence,
	102	+ enum FFPerlinRandomMode random_mode, unsigned int random_seed)
	103	+{
	104	+ int i;
	105	+
	106	+ perlin->period = period;
	107	+ perlin->octaves = octaves;
	108	+ perlin->persistence = persistence;
	109	+ perlin->random_mode = random_mode;
	110	+ perlin->random_seed = random_seed;
	111	+
	112	+ if (perlin->random_mode == FF_PERLIN_RANDOM_MODE_KEN) {
	113	+ for (i = 0; i < 512; i++) {
	114	+ perlin->permutations[i] = ken_permutations[i % 256];
	115	+ }
	116	+ } else {
	117	+ AVLFG lfg;
	118	+ uint8_t random_permutations[256];
	119	+
	120	+ if (perlin->random_mode == FF_PERLIN_RANDOM_MODE_RANDOM)
	121	+ perlin->random_seed = av_get_random_seed();
	122	+
	123	+ av_lfg_init(&lfg, perlin->random_seed);
	124	+
	125	+ for (i = 0; i < 256; i++) {
	126	+ random_permutations[i] = i;
	127	+ }
	128	+
	129	+ for (i = 0; i < 256; i++) {
	130	+ unsigned int random_idx = av_lfg_get(&lfg) % (256-i);
	131	+ uint8_t random_val = random_permutations[random_idx];
	132	+ random_permutations[random_idx] = random_permutations[256-i];
	133	+
	134	+ perlin->permutations[i] = perlin->permutations[i+256] = random_val;
	135	+ }
	136	+ }
	137	+
	138	+ return 0;
	139	+}
	140	+
	141	+static double perlin_get(FFPerlin *perlin, double x, double y, double z)
	142	+{
	143	+ int xi, yi, zi;
	144	+ double xf, yf, zf;
	145	+ double u, v, w;
	146	+ const uint8_t *p = perlin->permutations;
	147	+ double period = perlin->period;
	148	+ int aaa, aba, aab, abb, baa, bba, bab, bbb;
	149	+ double x1, x2, y1, y2;
	150	+
	151	+ if (perlin->period > 0) {
	152	+ // If we have any period on, change the coordinates to their "local" repetitions
	153	+ x = fmod(x, perlin->period);
	154	+ y = fmod(y, perlin->period);
	155	+ z = fmod(z, perlin->period);
	156	+ }
	157	+
	158	+ // Calculate the "unit cube" that the point asked will be located in
	159	+ // The left bound is ( \|_x_\|,\|_y_\|,\|_z_\| ) and the right bound is that
	160	+ // plus 1. Next we calculate the location (from 0.0 to 1.0) in that cube.
	161	+ xi = (int)x & 255;
	162	+ yi = (int)y & 255;
	163	+ zi = (int)z & 255;
	164	+
	165	+ xf = x - (int)x;
	166	+ yf = y - (int)y;
	167	+ zf = z - (int)z;
	168	+
	169	+ // We also fade the location to smooth the result.
	170	+ u = fade(xf);
	171	+ v = fade(yf);
	172	+ w = fade(zf);
	173	+
	174	+ aaa = p[p[p[ xi ] + yi ] + zi ];
	175	+ aba = p[p[p[ xi ] + inc(yi, period)] + zi ];
	176	+ aab = p[p[p[ xi ] + yi ] + inc(zi, period)];
	177	+ abb = p[p[p[ xi ] + inc(yi, period)] + inc(zi, period)];
	178	+ baa = p[p[p[inc(xi, period)] + yi ] + zi ];
	179	+ bba = p[p[p[inc(xi, period)] + inc(yi, period)] + zi ];
	180	+ bab = p[p[p[inc(xi, period)] + yi ] + inc(zi, period)];
	181	+ bbb = p[p[p[inc(xi, period)] + inc(yi, period)] + inc(zi, period)];
	182	+
	183	+ // The gradient function calculates the dot product between a pseudorandom
	184	+ // gradient vector and the vector from the input coordinate to the 8
	185	+ // surrounding points in its unit cube.
	186	+ // This is all then lerped together as a sort of weighted average based on the faded (u,v,w)
	187	+ // values we made earlier.
	188	+ x1 = lerp(grad(aaa, xf , yf , zf),
	189	+ grad(baa, xf-1, yf , zf),
	190	+ u);
	191	+ x2 = lerp(grad(aba, xf , yf-1, zf),
	192	+ grad(bba, xf-1, yf-1, zf),
	193	+ u);
	194	+ y1 = lerp(x1, x2, v);
	195	+
	196	+ x1 = lerp(grad(aab, xf , yf , zf-1),
	197	+ grad(bab, xf-1, yf , zf-1),
	198	+ u);
	199	+ x2 = lerp(grad(abb, xf , yf-1, zf-1),
	200	+ grad(bbb, xf-1, yf-1, zf-1),
	201	+ u);
	202	+ y2 = lerp(x1, x2, v);
	203	+
	204	+ // For convenience we bound it to 0 - 1 (theoretical min/max before is -1 - 1)
	205	+ return (lerp(y1, y2, w) + 1) / 2;
	206	+}
	207	+
	208	+double ff_perlin_get(FFPerlin *perlin, double x, double y, double z)
	209	+{
	210	+ double total = 0;
	211	+ double frequency = 1;
	212	+ double amplitude = 1;
	213	+ double max_value = 0; // Used for normalizing result to 0.0 - 1.0
	214	+
	215	+ for (int i = 0; i < perlin->octaves; i++) {
	216	+ total += perlin_get(perlin, x * frequency, y * frequency, z * frequency) * amplitude;
	217	+ max_value += amplitude;
	218	+ amplitude *= perlin->persistence;
	219	+ frequency *= 2;
	220	+ }
	221	+
	222	+ return total / max_value;
	223	+}
	224	+

libavfilter/perlin.h+101−0

@@ -0,0 +1,101 @@
	1	+/*
	2	+ * Perlin noise generator
	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	+ * Perlin Noise generator
	24	+ */
	25	+
	26	+#ifndef AVFILTER_PERLIN_H
	27	+#define AVFILTER_PERLIN_H
	28	+
	29	+#include <stdint.h>
	30	+
	31	+enum FFPerlinRandomMode {
	32	+ FF_PERLIN_RANDOM_MODE_RANDOM,
	33	+ FF_PERLIN_RANDOM_MODE_KEN,
	34	+ FF_PERLIN_RANDOM_MODE_SEED,
	35	+ FF_PERLIN_RANDOM_MODE_NB
	36	+};
	37	+
	38	+/**
	39	+ * Perlin generator context. This needs to be initialized with the
	40	+ * parameters used to generate the Perlin noise.
	41	+ */
	42	+typedef struct FFPerlin {
	43	+ /**
	44	+ * spatial repeat period, if negative it is ignored
	45	+ */
	46	+ double period;
	47	+
	48	+ /**
	49	+ * total number of components making up the noise, each one with
	50	+ * doubled frequency
	51	+ */
	52	+ int octaves;
	53	+
	54	+ /**
	55	+ * ratio used to compute the amplitude of the next octave
	56	+ * component with respect to the previous component
	57	+ */
	58	+ double persistence;
	59	+
	60	+ /**
	61	+ * permutations array used to compute the Perlin noise hash
	62	+ */
	63	+ uint8_t permutations[512];
	64	+
	65	+ /**
	66	+ * define how to compute the permutations array
	67	+ */
	68	+ enum FFPerlinRandomMode random_mode;
	69	+
	70	+ /**
	71	+ * when random_mode is set FF_PERLIN_RANDOM_MODE_RANDOM, set random
	72	+ * seed used to compute the permutations array
	73	+ */
	74	+ unsigned int random_seed;
	75	+} FFPerlin;
	76	+
	77	+/**
	78	+ * Initialize the Perlin noise generator with parameters.
	79	+ *
	80	+ * @param perlin Perlin noise generator context
	81	+ * @param period spatial repeat period, if negative it is ignored
	82	+ * @param octaves total number of components making up the noise, each one with doubled frequency
	83	+ * @param persistence define ratio used to compute the amplitude of the next octave
	84	+ * component with respect to the previous component
	85	+ * @param random_mode define how to compute the permutations array
	86	+ * @param random_seed when random_mode is set to FF_PERLIN_RANDOM_MODE_RANDOM, set random
	87	+ * seed used to compute the permutations array
	88	+ * @return a negative AVERROR code in case of error, a non negative value otherwise
	89	+ */
	90	+int ff_perlin_init(FFPerlin *perlin, double period, int octaves, double persistence,
	91	+ enum FFPerlinRandomMode random_mode, unsigned int random_seed);
	92	+
	93	+/**
	94	+ * Compute Perlin noise given the x, y, z coordinates.
	95	+ *
	96	+ * @param perlin Perlin noise generator context
	97	+ * @return normalized value for the perlin noise, in the range [0, 1]
	98	+ */
	99	+double ff_perlin_get(FFPerlin *perlin, double x, double y, double z);
	100	+
	101	+#endif /* AVFILTER_PERLIN_H */

libavfilter/vsrc_perlin.c+169−0

@@ -0,0 +1,169 @@
	1	+/*
	2	+ * This file is part of FFmpeg.
	3	+ *
	4	+ * FFmpeg is free software; you can redistribute it and/or
	5	+ * modify it under the terms of the GNU Lesser General Public
	6	+ * License as published by the Free Software Foundation; either
	7	+ * version 2.1 of the License, or (at your option) any later version.
	8	+ *
	9	+ * FFmpeg is distributed in the hope that it will be useful,
	10	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	12	+ * Lesser General Public License for more details.
	13	+ *
	14	+ * You should have received a copy of the GNU Lesser General Public
	15	+ * License along with FFmpeg; if not, write to the Free Software
	16	+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	17	+ */
	18	+
	19	+/**
	20	+ * @file
	21	+ * Perlin noise generator
	22	+ */
	23	+
	24	+#include <float.h>
	25	+
	26	+#include "perlin.h"
	27	+#include "libavutil/lfg.h"
	28	+#include "libavutil/opt.h"
	29	+#include "avfilter.h"
	30	+#include "internal.h"
	31	+#include "formats.h"
	32	+#include "video.h"
	33	+
	34	+typedef struct PerlinContext {
	35	+ const AVClass *class;
	36	+
	37	+ int w, h;
	38	+ AVRational frame_rate;
	39	+
	40	+ FFPerlin perlin;
	41	+ int octaves;
	42	+ double persistence;
	43	+ unsigned int random_seed;
	44	+ enum FFPerlinRandomMode random_mode;
	45	+
	46	+ double xscale, yscale, tscale;
	47	+ uint64_t pts;
	48	+} PerlinContext;
	49	+
	50	+#define OFFSET(x) offsetof(PerlinContext, x)
	51	+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM\|AV_OPT_FLAG_FILTERING_PARAM
	52	+
	53	+static const AVOption perlin_options[] = {
	54	+ { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="320x240"}, 0, 0, FLAGS },
	55	+ { "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="320x240"}, 0, 0, FLAGS },
	56	+ { "rate", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
	57	+ { "r", "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="25"}, 0, INT_MAX, FLAGS },
	58	+ { "octaves", "set the number of components to use to generate the noise", OFFSET(octaves), AV_OPT_TYPE_INT, {.i64=1}, 1, INT_MAX, FLAGS },
	59	+ { "persistence", "set the octaves persistence", OFFSET(persistence), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, DBL_MAX, FLAGS },
	60	+
	61	+ { "xscale", "set x-scale factor", OFFSET(xscale), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, DBL_MAX, FLAGS },
	62	+ { "yscale", "set y-scale factor", OFFSET(yscale), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, DBL_MAX, FLAGS },
	63	+ { "tscale", "set t-scale factor", OFFSET(tscale), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, DBL_MAX, FLAGS },
	64	+
	65	+ { "random_mode", "set random mode used to compute initial pattern", OFFSET(random_mode), AV_OPT_TYPE_INT, {.i64=FF_PERLIN_RANDOM_MODE_RANDOM}, 0, FF_PERLIN_RANDOM_MODE_NB-1, FLAGS, .unit = "random_mode" },
	66	+ { "random", "compute and use random seed", 0, AV_OPT_TYPE_CONST, {.i64=FF_PERLIN_RANDOM_MODE_RANDOM}, 0, 0, FLAGS, .unit = "random_mode" },
	67	+ { "ken", "use the predefined initial pattern defined by Ken Perlin in the original article", 0, AV_OPT_TYPE_CONST, {.i64=FF_PERLIN_RANDOM_MODE_KEN}, 0, 0, FLAGS, .unit = "random_mode" },
	68	+ { "seed", "use the value specified by random_seed", 0, AV_OPT_TYPE_CONST, {.i64=FF_PERLIN_RANDOM_MODE_SEED}, 0, 0, FLAGS, .unit="random_mode" },
	69	+
	70	+ { "random_seed", "set the seed for filling the initial pattern", OFFSET(random_seed), AV_OPT_TYPE_UINT, {.i64=0}, 0, UINT_MAX, FLAGS },
	71	+ { "seed", "set the seed for filling the initial pattern", OFFSET(random_seed), AV_OPT_TYPE_UINT, {.i64=0}, 0, UINT_MAX, FLAGS },
	72	+ { NULL }
	73	+};
	74	+
	75	+AVFILTER_DEFINE_CLASS(perlin);
	76	+
	77	+static av_cold int init(AVFilterContext *ctx)
	78	+{
	79	+ PerlinContext *perlin = ctx->priv;
	80	+ int ret;
	81	+
	82	+ if (ret = ff_perlin_init(&perlin->perlin, -1, perlin->octaves, perlin->persistence,
	83	+ perlin->random_mode, perlin->random_seed)) {
	84	+ return ret;
	85	+ }
	86	+
	87	+ av_log(ctx, AV_LOG_VERBOSE,
	88	+ "s:%dx%d r:%d/%d octaves:%d persistence:%f xscale:%f yscale:%f tscale:%f\n",
	89	+ perlin->w, perlin->h, perlin->frame_rate.num, perlin->frame_rate.den,
	90	+ perlin->octaves, perlin->persistence,
	91	+ perlin->xscale, perlin->yscale, perlin->tscale);
	92	+ return 0;
	93	+}
	94	+
	95	+static int config_props(AVFilterLink *outlink)
	96	+{
	97	+ PerlinContext *perlin = outlink->src->priv;
	98	+
	99	+ outlink->w = perlin->w;
	100	+ outlink->h = perlin->h;
	101	+ outlink->time_base = av_inv_q(perlin->frame_rate);
	102	+ outlink->frame_rate = perlin->frame_rate;
	103	+
	104	+ return 0;
	105	+}
	106	+
	107	+static int request_frame(AVFilterLink *outlink)
	108	+{
	109	+ AVFilterContext *ctx = outlink->src;
	110	+ PerlinContext *perlin = ctx->priv;
	111	+ AVFrame *picref = ff_get_video_buffer(outlink, perlin->w, perlin->h);
	112	+ int i, j;
	113	+ uint8_t data0, data;
	114	+ double x, y, t;
	115	+
	116	+ if (!picref)
	117	+ return AVERROR(ENOMEM);
	118	+
	119	+ picref->sample_aspect_ratio = (AVRational) {1, 1};
	120	+ picref->pts = perlin->pts++;
	121	+ picref->duration = 1;
	122	+
	123	+ t = perlin->tscale * (perlin->pts * av_q2d(outlink->time_base));
	124	+ data0 = picref->data[0];
	125	+
	126	+ for (i = 0; i < perlin->h; i++) {
	127	+ y = perlin->yscale * (double)i / perlin->h;
	128	+
	129	+ data = data0;
	130	+
	131	+ for (j = 0; j < perlin->w; j++) {
	132	+ double res;
	133	+ x = perlin->xscale * (double)j / perlin->w;
	134	+ res = ff_perlin_get(&perlin->perlin, x, y, t);
	135	+ av_log(ctx, AV_LOG_DEBUG, "x:%f y:%f t:%f => %f\n", x, y, t, res);
	136	+ data++ = res 255;
	137	+ }
	138	+ data0 += picref->linesize[0];
	139	+ }
	140	+
	141	+ return ff_filter_frame(outlink, picref);
	142	+}
	143	+
	144	+static int query_formats(AVFilterContext *ctx)
	145	+{
	146	+ enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };
	147	+
	148	+ return ff_set_common_formats_from_list(ctx, pix_fmts);
	149	+}
	150	+
	151	+static const AVFilterPad perlin_outputs[] = {
	152	+ {
	153	+ .name = "default",
	154	+ .type = AVMEDIA_TYPE_VIDEO,
	155	+ .request_frame = request_frame,
	156	+ .config_props = config_props,
	157	+ },
	158	+};
	159	+
	160	+const AVFilter ff_vsrc_perlin = {
	161	+ .name = "perlin",
	162	+ .description = NULL_IF_CONFIG_SMALL("Generate Perlin noise"),
	163	+ .priv_size = sizeof(PerlinContext),
	164	+ .priv_class = &perlin_class,
	165	+ .init = init,
	166	+ .inputs = NULL,
	167	+ FILTER_OUTPUTS(perlin_outputs),
	168	+ FILTER_QUERY_FUNC(query_formats),
	169	+};

lavfi: add Perlin noise generator

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