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/imgutils.h"
31 #include "libavutil/internal.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/opt.h"
34 #include "libavutil/pixdesc.h"
35
36 #include "avfilter.h"
37 #include "colorspace.h"
38 #include "formats.h"
39 #include "internal.h"
40 #include "video.h"
41
42 enum TonemapAlgorithm {
43 TONEMAP_NONE,
44 TONEMAP_LINEAR,
45 TONEMAP_GAMMA,
46 TONEMAP_CLIP,
47 TONEMAP_REINHARD,
48 TONEMAP_HABLE,
49 TONEMAP_MOBIUS,
50 TONEMAP_MAX,
51 };
52
53 static const struct LumaCoefficients luma_coefficients[AVCOL_SPC_NB] = {
54 [AVCOL_SPC_FCC] = { 0.30, 0.59, 0.11 },
55 [AVCOL_SPC_BT470BG] = { 0.299, 0.587, 0.114 },
56 [AVCOL_SPC_SMPTE170M] = { 0.299, 0.587, 0.114 },
57 [AVCOL_SPC_BT709] = { 0.2126, 0.7152, 0.0722 },
58 [AVCOL_SPC_SMPTE240M] = { 0.212, 0.701, 0.087 },
59 [AVCOL_SPC_BT2020_NCL] = { 0.2627, 0.6780, 0.0593 },
60 [AVCOL_SPC_BT2020_CL] = { 0.2627, 0.6780, 0.0593 },
61 };
62
63 typedef struct TonemapContext {
64 const AVClass *class;
65
66 enum TonemapAlgorithm tonemap;
67 double param;
68 double desat;
69 double peak;
70
71 const struct LumaCoefficients *coeffs;
72 } TonemapContext;
73
74 static const enum AVPixelFormat pix_fmts[] = {
75 AV_PIX_FMT_GBRPF32,
76 AV_PIX_FMT_GBRAPF32,
77 AV_PIX_FMT_NONE,
78 };
79
query_formats(AVFilterContext * ctx)80 static int query_formats(AVFilterContext *ctx)
81 {
82 return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
83 }
84
init(AVFilterContext * ctx)85 static av_cold int init(AVFilterContext *ctx)
86 {
87 TonemapContext *s = ctx->priv;
88
89 switch(s->tonemap) {
90 case TONEMAP_GAMMA:
91 if (isnan(s->param))
92 s->param = 1.8f;
93 break;
94 case TONEMAP_REINHARD:
95 if (!isnan(s->param))
96 s->param = (1.0f - s->param) / s->param;
97 break;
98 case TONEMAP_MOBIUS:
99 if (isnan(s->param))
100 s->param = 0.3f;
101 break;
102 }
103
104 if (isnan(s->param))
105 s->param = 1.0f;
106
107 return 0;
108 }
109
hable(float in)110 static float hable(float in)
111 {
112 float a = 0.15f, b = 0.50f, c = 0.10f, d = 0.20f, e = 0.02f, f = 0.30f;
113 return (in * (in * a + b * c) + d * e) / (in * (in * a + b) + d * f) - e / f;
114 }
115
mobius(float in,float j,double peak)116 static float mobius(float in, float j, double peak)
117 {
118 float a, b;
119
120 if (in <= j)
121 return in;
122
123 a = -j * j * (peak - 1.0f) / (j * j - 2.0f * j + peak);
124 b = (j * j - 2.0f * j * peak + peak) / FFMAX(peak - 1.0f, 1e-6);
125
126 return (b * b + 2.0f * b * j + j * j) / (b - a) * (in + a) / (in + b);
127 }
128
129 #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)130 static void tonemap(TonemapContext *s, AVFrame *out, const AVFrame *in,
131 const AVPixFmtDescriptor *desc, int x, int y, double peak)
132 {
133 const float *r_in = (const float *)(in->data[0] + x * desc->comp[0].step + y * in->linesize[0]);
134 const float *b_in = (const float *)(in->data[1] + x * desc->comp[1].step + y * in->linesize[1]);
135 const float *g_in = (const float *)(in->data[2] + x * desc->comp[2].step + y * in->linesize[2]);
136 float *r_out = (float *)(out->data[0] + x * desc->comp[0].step + y * out->linesize[0]);
137 float *b_out = (float *)(out->data[1] + x * desc->comp[1].step + y * out->linesize[1]);
138 float *g_out = (float *)(out->data[2] + x * desc->comp[2].step + y * out->linesize[2]);
139 float sig, sig_orig;
140
141 /* load values */
142 *r_out = *r_in;
143 *b_out = *b_in;
144 *g_out = *g_in;
145
146 /* desaturate to prevent unnatural colors */
147 if (s->desat > 0) {
148 float luma = s->coeffs->cr * *r_in + s->coeffs->cg * *g_in + s->coeffs->cb * *b_in;
149 float overbright = FFMAX(luma - s->desat, 1e-6) / FFMAX(luma, 1e-6);
150 *r_out = MIX(*r_in, luma, overbright);
151 *g_out = MIX(*g_in, luma, overbright);
152 *b_out = MIX(*b_in, luma, overbright);
153 }
154
155 /* pick the brightest component, reducing the value range as necessary
156 * to keep the entire signal in range and preventing discoloration due to
157 * out-of-bounds clipping */
158 sig = FFMAX(FFMAX3(*r_out, *g_out, *b_out), 1e-6);
159 sig_orig = sig;
160
161 switch(s->tonemap) {
162 default:
163 case TONEMAP_NONE:
164 // do nothing
165 break;
166 case TONEMAP_LINEAR:
167 sig = sig * s->param / peak;
168 break;
169 case TONEMAP_GAMMA:
170 sig = sig > 0.05f ? pow(sig / peak, 1.0f / s->param)
171 : sig * pow(0.05f / peak, 1.0f / s->param) / 0.05f;
172 break;
173 case TONEMAP_CLIP:
174 sig = av_clipf(sig * s->param, 0, 1.0f);
175 break;
176 case TONEMAP_HABLE:
177 sig = hable(sig) / hable(peak);
178 break;
179 case TONEMAP_REINHARD:
180 sig = sig / (sig + s->param) * (peak + s->param) / peak;
181 break;
182 case TONEMAP_MOBIUS:
183 sig = mobius(sig, s->param, peak);
184 break;
185 }
186
187 /* apply the computed scale factor to the color,
188 * linearly to prevent discoloration */
189 *r_out *= sig / sig_orig;
190 *g_out *= sig / sig_orig;
191 *b_out *= sig / sig_orig;
192 }
193
194 typedef struct ThreadData {
195 AVFrame *in, *out;
196 const AVPixFmtDescriptor *desc;
197 double peak;
198 } ThreadData;
199
tonemap_slice(AVFilterContext * ctx,void * arg,int jobnr,int nb_jobs)200 static int tonemap_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
201 {
202 TonemapContext *s = ctx->priv;
203 ThreadData *td = arg;
204 AVFrame *in = td->in;
205 AVFrame *out = td->out;
206 const AVPixFmtDescriptor *desc = td->desc;
207 const int slice_start = (in->height * jobnr) / nb_jobs;
208 const int slice_end = (in->height * (jobnr+1)) / nb_jobs;
209 double peak = td->peak;
210
211 for (int y = slice_start; y < slice_end; y++)
212 for (int x = 0; x < out->width; x++)
213 tonemap(s, out, in, desc, x, y, peak);
214
215 return 0;
216 }
217
filter_frame(AVFilterLink * link,AVFrame * in)218 static int filter_frame(AVFilterLink *link, AVFrame *in)
219 {
220 AVFilterContext *ctx = link->dst;
221 TonemapContext *s = ctx->priv;
222 AVFilterLink *outlink = ctx->outputs[0];
223 ThreadData td;
224 AVFrame *out;
225 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
226 const AVPixFmtDescriptor *odesc = av_pix_fmt_desc_get(outlink->format);
227 int ret, x, y;
228 double peak = s->peak;
229
230 if (!desc || !odesc) {
231 av_frame_free(&in);
232 return AVERROR_BUG;
233 }
234
235 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
236 if (!out) {
237 av_frame_free(&in);
238 return AVERROR(ENOMEM);
239 }
240
241 ret = av_frame_copy_props(out, in);
242 if (ret < 0) {
243 av_frame_free(&in);
244 av_frame_free(&out);
245 return ret;
246 }
247
248 /* input and output transfer will be linear */
249 if (in->color_trc == AVCOL_TRC_UNSPECIFIED) {
250 av_log(s, AV_LOG_WARNING, "Untagged transfer, assuming linear light\n");
251 out->color_trc = AVCOL_TRC_LINEAR;
252 } else if (in->color_trc != AVCOL_TRC_LINEAR)
253 av_log(s, AV_LOG_WARNING, "Tonemapping works on linear light only\n");
254
255 /* read peak from side data if not passed in */
256 if (!peak) {
257 peak = ff_determine_signal_peak(in);
258 av_log(s, AV_LOG_DEBUG, "Computed signal peak: %f\n", peak);
259 }
260
261 /* load original color space even if pixel format is RGB to compute overbrights */
262 s->coeffs = &luma_coefficients[in->colorspace];
263 if (s->desat > 0 && (in->colorspace == AVCOL_SPC_UNSPECIFIED || !s->coeffs)) {
264 if (in->colorspace == AVCOL_SPC_UNSPECIFIED)
265 av_log(s, AV_LOG_WARNING, "Missing color space information, ");
266 else if (!s->coeffs)
267 av_log(s, AV_LOG_WARNING, "Unsupported color space '%s', ",
268 av_color_space_name(in->colorspace));
269 av_log(s, AV_LOG_WARNING, "desaturation is disabled\n");
270 s->desat = 0;
271 }
272
273 /* do the tone map */
274 td.out = out;
275 td.in = in;
276 td.desc = desc;
277 td.peak = peak;
278 ctx->internal->execute(ctx, tonemap_slice, &td, NULL, FFMIN(in->height, ff_filter_get_nb_threads(ctx)));
279
280 /* copy/generate alpha if needed */
281 if (desc->flags & AV_PIX_FMT_FLAG_ALPHA && odesc->flags & AV_PIX_FMT_FLAG_ALPHA) {
282 av_image_copy_plane(out->data[3], out->linesize[3],
283 in->data[3], in->linesize[3],
284 out->linesize[3], outlink->h);
285 } else if (odesc->flags & AV_PIX_FMT_FLAG_ALPHA) {
286 for (y = 0; y < out->height; y++) {
287 for (x = 0; x < out->width; x++) {
288 AV_WN32(out->data[3] + x * odesc->comp[3].step + y * out->linesize[3],
289 av_float2int(1.0f));
290 }
291 }
292 }
293
294 av_frame_free(&in);
295
296 ff_update_hdr_metadata(out, peak);
297
298 return ff_filter_frame(outlink, out);
299 }
300
301 #define OFFSET(x) offsetof(TonemapContext, x)
302 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
303 static const AVOption tonemap_options[] = {
304 { "tonemap", "tonemap algorithm selection", OFFSET(tonemap), AV_OPT_TYPE_INT, {.i64 = TONEMAP_NONE}, TONEMAP_NONE, TONEMAP_MAX - 1, FLAGS, "tonemap" },
305 { "none", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_NONE}, 0, 0, FLAGS, "tonemap" },
306 { "linear", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_LINEAR}, 0, 0, FLAGS, "tonemap" },
307 { "gamma", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_GAMMA}, 0, 0, FLAGS, "tonemap" },
308 { "clip", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_CLIP}, 0, 0, FLAGS, "tonemap" },
309 { "reinhard", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_REINHARD}, 0, 0, FLAGS, "tonemap" },
310 { "hable", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_HABLE}, 0, 0, FLAGS, "tonemap" },
311 { "mobius", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_MOBIUS}, 0, 0, FLAGS, "tonemap" },
312 { "param", "tonemap parameter", OFFSET(param), AV_OPT_TYPE_DOUBLE, {.dbl = NAN}, DBL_MIN, DBL_MAX, FLAGS },
313 { "desat", "desaturation strength", OFFSET(desat), AV_OPT_TYPE_DOUBLE, {.dbl = 2}, 0, DBL_MAX, FLAGS },
314 { "peak", "signal peak override", OFFSET(peak), AV_OPT_TYPE_DOUBLE, {.dbl = 0}, 0, DBL_MAX, FLAGS },
315 { NULL }
316 };
317
318 AVFILTER_DEFINE_CLASS(tonemap);
319
320 static const AVFilterPad tonemap_inputs[] = {
321 {
322 .name = "default",
323 .type = AVMEDIA_TYPE_VIDEO,
324 .filter_frame = filter_frame,
325 },
326 { NULL }
327 };
328
329 static const AVFilterPad tonemap_outputs[] = {
330 {
331 .name = "default",
332 .type = AVMEDIA_TYPE_VIDEO,
333 },
334 { NULL }
335 };
336
337 AVFilter ff_vf_tonemap = {
338 .name = "tonemap",
339 .description = NULL_IF_CONFIG_SMALL("Conversion to/from different dynamic ranges."),
340 .init = init,
341 .query_formats = query_formats,
342 .priv_size = sizeof(TonemapContext),
343 .priv_class = &tonemap_class,
344 .inputs = tonemap_inputs,
345 .outputs = tonemap_outputs,
346 .flags = AVFILTER_FLAG_SLICE_THREADS,
347 };
348