1 /*
2 * Copyright (c) 2017 Vittorio Giovara <vittorio.giovara@gmail.com>
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 * tonemap algorithms
24 */
25
26 #include <float.h>
27 #include <stdio.h>
28 #include <string.h>
29
30 #include "libavutil/csp.h"
31 #include "libavutil/imgutils.h"
32 #include "libavutil/internal.h"
33 #include "libavutil/intreadwrite.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/pixdesc.h"
36
37 #include "avfilter.h"
38 #include "colorspace.h"
39 #include "formats.h"
40 #include "internal.h"
41 #include "video.h"
42
43 enum TonemapAlgorithm {
44 TONEMAP_NONE,
45 TONEMAP_LINEAR,
46 TONEMAP_GAMMA,
47 TONEMAP_CLIP,
48 TONEMAP_REINHARD,
49 TONEMAP_HABLE,
50 TONEMAP_MOBIUS,
51 TONEMAP_MAX,
52 };
53
54 typedef struct TonemapContext {
55 const AVClass *class;
56
57 enum TonemapAlgorithm tonemap;
58 double param;
59 double desat;
60 double peak;
61
62 const AVLumaCoefficients *coeffs;
63 } TonemapContext;
64
init(AVFilterContext * ctx)65 static av_cold int init(AVFilterContext *ctx)
66 {
67 TonemapContext *s = ctx->priv;
68
69 switch(s->tonemap) {
70 case TONEMAP_GAMMA:
71 if (isnan(s->param))
72 s->param = 1.8f;
73 break;
74 case TONEMAP_REINHARD:
75 if (!isnan(s->param))
76 s->param = (1.0f - s->param) / s->param;
77 break;
78 case TONEMAP_MOBIUS:
79 if (isnan(s->param))
80 s->param = 0.3f;
81 break;
82 }
83
84 if (isnan(s->param))
85 s->param = 1.0f;
86
87 return 0;
88 }
89
hable(float in)90 static float hable(float in)
91 {
92 float a = 0.15f, b = 0.50f, c = 0.10f, d = 0.20f, e = 0.02f, f = 0.30f;
93 return (in * (in * a + b * c) + d * e) / (in * (in * a + b) + d * f) - e / f;
94 }
95
mobius(float in,float j,double peak)96 static float mobius(float in, float j, double peak)
97 {
98 float a, b;
99
100 if (in <= j)
101 return in;
102
103 a = -j * j * (peak - 1.0f) / (j * j - 2.0f * j + peak);
104 b = (j * j - 2.0f * j * peak + peak) / FFMAX(peak - 1.0f, 1e-6);
105
106 return (b * b + 2.0f * b * j + j * j) / (b - a) * (in + a) / (in + b);
107 }
108
109 #define MIX(x,y,a) (x) * (1 - (a)) + (y) * (a)
tonemap(TonemapContext * s,AVFrame * out,const AVFrame * in,const AVPixFmtDescriptor * desc,int x,int y,double peak)110 static void tonemap(TonemapContext *s, AVFrame *out, const AVFrame *in,
111 const AVPixFmtDescriptor *desc, int x, int y, double peak)
112 {
113 int map[3] = { desc->comp[0].plane, desc->comp[1].plane, desc->comp[2].plane };
114 const float *r_in = (const float *)(in->data[map[0]] + x * desc->comp[map[0]].step + y * in->linesize[map[0]]);
115 const float *g_in = (const float *)(in->data[map[1]] + x * desc->comp[map[1]].step + y * in->linesize[map[1]]);
116 const float *b_in = (const float *)(in->data[map[2]] + x * desc->comp[map[2]].step + y * in->linesize[map[2]]);
117 float *r_out = (float *)(out->data[map[0]] + x * desc->comp[map[0]].step + y * out->linesize[map[0]]);
118 float *g_out = (float *)(out->data[map[1]] + x * desc->comp[map[1]].step + y * out->linesize[map[1]]);
119 float *b_out = (float *)(out->data[map[2]] + x * desc->comp[map[2]].step + y * out->linesize[map[2]]);
120 float sig, sig_orig;
121
122 /* load values */
123 *r_out = *r_in;
124 *g_out = *g_in;
125 *b_out = *b_in;
126
127 /* desaturate to prevent unnatural colors */
128 if (s->desat > 0) {
129 float luma = av_q2d(s->coeffs->cr) * *r_in + av_q2d(s->coeffs->cg) * *g_in + av_q2d(s->coeffs->cb) * *b_in;
130 float overbright = FFMAX(luma - s->desat, 1e-6) / FFMAX(luma, 1e-6);
131 *r_out = MIX(*r_in, luma, overbright);
132 *g_out = MIX(*g_in, luma, overbright);
133 *b_out = MIX(*b_in, luma, overbright);
134 }
135
136 /* pick the brightest component, reducing the value range as necessary
137 * to keep the entire signal in range and preventing discoloration due to
138 * out-of-bounds clipping */
139 sig = FFMAX(FFMAX3(*r_out, *g_out, *b_out), 1e-6);
140 sig_orig = sig;
141
142 switch(s->tonemap) {
143 default:
144 case TONEMAP_NONE:
145 // do nothing
146 break;
147 case TONEMAP_LINEAR:
148 sig = sig * s->param / peak;
149 break;
150 case TONEMAP_GAMMA:
151 sig = sig > 0.05f ? pow(sig / peak, 1.0f / s->param)
152 : sig * pow(0.05f / peak, 1.0f / s->param) / 0.05f;
153 break;
154 case TONEMAP_CLIP:
155 sig = av_clipf(sig * s->param, 0, 1.0f);
156 break;
157 case TONEMAP_HABLE:
158 sig = hable(sig) / hable(peak);
159 break;
160 case TONEMAP_REINHARD:
161 sig = sig / (sig + s->param) * (peak + s->param) / peak;
162 break;
163 case TONEMAP_MOBIUS:
164 sig = mobius(sig, s->param, peak);
165 break;
166 }
167
168 /* apply the computed scale factor to the color,
169 * linearly to prevent discoloration */
170 *r_out *= sig / sig_orig;
171 *g_out *= sig / sig_orig;
172 *b_out *= sig / sig_orig;
173 }
174
175 typedef struct ThreadData {
176 AVFrame *in, *out;
177 const AVPixFmtDescriptor *desc;
178 double peak;
179 } ThreadData;
180
tonemap_slice(AVFilterContext * ctx,void * arg,int jobnr,int nb_jobs)181 static int tonemap_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
182 {
183 TonemapContext *s = ctx->priv;
184 ThreadData *td = arg;
185 AVFrame *in = td->in;
186 AVFrame *out = td->out;
187 const AVPixFmtDescriptor *desc = td->desc;
188 const int slice_start = (in->height * jobnr) / nb_jobs;
189 const int slice_end = (in->height * (jobnr+1)) / nb_jobs;
190 double peak = td->peak;
191
192 for (int y = slice_start; y < slice_end; y++)
193 for (int x = 0; x < out->width; x++)
194 tonemap(s, out, in, desc, x, y, peak);
195
196 return 0;
197 }
198
filter_frame(AVFilterLink * link,AVFrame * in)199 static int filter_frame(AVFilterLink *link, AVFrame *in)
200 {
201 AVFilterContext *ctx = link->dst;
202 TonemapContext *s = ctx->priv;
203 AVFilterLink *outlink = ctx->outputs[0];
204 ThreadData td;
205 AVFrame *out;
206 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
207 const AVPixFmtDescriptor *odesc = av_pix_fmt_desc_get(outlink->format);
208 int ret, x, y;
209 double peak = s->peak;
210
211 if (!desc || !odesc) {
212 av_frame_free(&in);
213 return AVERROR_BUG;
214 }
215
216 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
217 if (!out) {
218 av_frame_free(&in);
219 return AVERROR(ENOMEM);
220 }
221
222 ret = av_frame_copy_props(out, in);
223 if (ret < 0) {
224 av_frame_free(&in);
225 av_frame_free(&out);
226 return ret;
227 }
228
229 /* input and output transfer will be linear */
230 if (in->color_trc == AVCOL_TRC_UNSPECIFIED) {
231 av_log(s, AV_LOG_WARNING, "Untagged transfer, assuming linear light\n");
232 out->color_trc = AVCOL_TRC_LINEAR;
233 } else if (in->color_trc != AVCOL_TRC_LINEAR)
234 av_log(s, AV_LOG_WARNING, "Tonemapping works on linear light only\n");
235
236 /* read peak from side data if not passed in */
237 if (!peak) {
238 peak = ff_determine_signal_peak(in);
239 av_log(s, AV_LOG_DEBUG, "Computed signal peak: %f\n", peak);
240 }
241
242 /* load original color space even if pixel format is RGB to compute overbrights */
243 s->coeffs = av_csp_luma_coeffs_from_avcsp(in->colorspace);
244 if (s->desat > 0 && (in->colorspace == AVCOL_SPC_UNSPECIFIED || !s->coeffs)) {
245 if (in->colorspace == AVCOL_SPC_UNSPECIFIED)
246 av_log(s, AV_LOG_WARNING, "Missing color space information, ");
247 else if (!s->coeffs)
248 av_log(s, AV_LOG_WARNING, "Unsupported color space '%s', ",
249 av_color_space_name(in->colorspace));
250 av_log(s, AV_LOG_WARNING, "desaturation is disabled\n");
251 s->desat = 0;
252 }
253
254 /* do the tone map */
255 td.out = out;
256 td.in = in;
257 td.desc = desc;
258 td.peak = peak;
259 ff_filter_execute(ctx, tonemap_slice, &td, NULL,
260 FFMIN(in->height, ff_filter_get_nb_threads(ctx)));
261
262 /* copy/generate alpha if needed */
263 if (desc->flags & AV_PIX_FMT_FLAG_ALPHA && odesc->flags & AV_PIX_FMT_FLAG_ALPHA) {
264 av_image_copy_plane(out->data[3], out->linesize[3],
265 in->data[3], in->linesize[3],
266 out->linesize[3], outlink->h);
267 } else if (odesc->flags & AV_PIX_FMT_FLAG_ALPHA) {
268 for (y = 0; y < out->height; y++) {
269 for (x = 0; x < out->width; x++) {
270 AV_WN32(out->data[3] + x * odesc->comp[3].step + y * out->linesize[3],
271 av_float2int(1.0f));
272 }
273 }
274 }
275
276 av_frame_free(&in);
277
278 ff_update_hdr_metadata(out, peak);
279
280 return ff_filter_frame(outlink, out);
281 }
282
283 #define OFFSET(x) offsetof(TonemapContext, x)
284 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
285 static const AVOption tonemap_options[] = {
286 { "tonemap", "tonemap algorithm selection", OFFSET(tonemap), AV_OPT_TYPE_INT, {.i64 = TONEMAP_NONE}, TONEMAP_NONE, TONEMAP_MAX - 1, FLAGS, "tonemap" },
287 { "none", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_NONE}, 0, 0, FLAGS, "tonemap" },
288 { "linear", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_LINEAR}, 0, 0, FLAGS, "tonemap" },
289 { "gamma", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_GAMMA}, 0, 0, FLAGS, "tonemap" },
290 { "clip", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_CLIP}, 0, 0, FLAGS, "tonemap" },
291 { "reinhard", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_REINHARD}, 0, 0, FLAGS, "tonemap" },
292 { "hable", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_HABLE}, 0, 0, FLAGS, "tonemap" },
293 { "mobius", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_MOBIUS}, 0, 0, FLAGS, "tonemap" },
294 { "param", "tonemap parameter", OFFSET(param), AV_OPT_TYPE_DOUBLE, {.dbl = NAN}, DBL_MIN, DBL_MAX, FLAGS },
295 { "desat", "desaturation strength", OFFSET(desat), AV_OPT_TYPE_DOUBLE, {.dbl = 2}, 0, DBL_MAX, FLAGS },
296 { "peak", "signal peak override", OFFSET(peak), AV_OPT_TYPE_DOUBLE, {.dbl = 0}, 0, DBL_MAX, FLAGS },
297 { NULL }
298 };
299
300 AVFILTER_DEFINE_CLASS(tonemap);
301
302 static const AVFilterPad tonemap_inputs[] = {
303 {
304 .name = "default",
305 .type = AVMEDIA_TYPE_VIDEO,
306 .filter_frame = filter_frame,
307 },
308 };
309
310 static const AVFilterPad tonemap_outputs[] = {
311 {
312 .name = "default",
313 .type = AVMEDIA_TYPE_VIDEO,
314 },
315 };
316
317 const AVFilter ff_vf_tonemap = {
318 .name = "tonemap",
319 .description = NULL_IF_CONFIG_SMALL("Conversion to/from different dynamic ranges."),
320 .init = init,
321 .priv_size = sizeof(TonemapContext),
322 .priv_class = &tonemap_class,
323 FILTER_INPUTS(tonemap_inputs),
324 FILTER_OUTPUTS(tonemap_outputs),
325 FILTER_PIXFMTS(AV_PIX_FMT_GBRPF32, AV_PIX_FMT_GBRAPF32),
326 .flags = AVFILTER_FLAG_SLICE_THREADS,
327 };
328