/*
* Copyright (c) 2017 Vittorio Giovara <vittorio.giovara@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* tonemap algorithms
*/
#include <float.h>
#include <stdio.h>
#include <string.h>
#include "libavutil/imgutils.h"
#include "libavutil/internal.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mastering_display_metadata.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#define REFERENCE_WHITE 100.0f
enum TonemapAlgorithm {
TONEMAP_NONE,
TONEMAP_LINEAR,
TONEMAP_GAMMA,
TONEMAP_CLIP,
TONEMAP_REINHARD,
TONEMAP_HABLE,
TONEMAP_MOBIUS,
TONEMAP_MAX,
};
typedef struct LumaCoefficients {
double cr, cg, cb;
} LumaCoefficients;
static const struct LumaCoefficients luma_coefficients[AVCOL_SPC_NB] = {
[AVCOL_SPC_FCC] = { 0.30, 0.59, 0.11 },
[AVCOL_SPC_BT470BG] = { 0.299, 0.587, 0.114 },
[AVCOL_SPC_SMPTE170M] = { 0.299, 0.587, 0.114 },
[AVCOL_SPC_BT709] = { 0.2126, 0.7152, 0.0722 },
[AVCOL_SPC_SMPTE240M] = { 0.212, 0.701, 0.087 },
[AVCOL_SPC_BT2020_NCL] = { 0.2627, 0.6780, 0.0593 },
[AVCOL_SPC_BT2020_CL] = { 0.2627, 0.6780, 0.0593 },
};
typedef struct TonemapContext {
const AVClass *class;
enum TonemapAlgorithm tonemap;
double param;
double desat;
double peak;
const LumaCoefficients *coeffs;
} TonemapContext;
static const enum AVPixelFormat pix_fmts[] = {
AV_PIX_FMT_GBRPF32,
AV_PIX_FMT_GBRAPF32,
AV_PIX_FMT_NONE,
};
static int query_formats(AVFilterContext *ctx)
{
return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
}
static av_cold int init(AVFilterContext *ctx)
{
TonemapContext *s = ctx->priv;
switch(s->tonemap) {
case TONEMAP_GAMMA:
if (isnan(s->param))
s->param = 1.8f;
break;
case TONEMAP_REINHARD:
if (!isnan(s->param))
s->param = (1.0f - s->param) / s->param;
break;
case TONEMAP_MOBIUS:
if (isnan(s->param))
s->param = 0.3f;
break;
}
if (isnan(s->param))
s->param = 1.0f;
return 0;
}
static double determine_signal_peak(AVFrame *in)
{
AVFrameSideData *sd = av_frame_get_side_data(in, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL);
double peak = 0;
if (sd) {
AVContentLightMetadata *clm = (AVContentLightMetadata *)sd->data;
peak = clm->MaxCLL / REFERENCE_WHITE;
}
sd = av_frame_get_side_data(in, AV_FRAME_DATA_MASTERING_DISPLAY_METADATA);
if (!peak && sd) {
AVMasteringDisplayMetadata *metadata = (AVMasteringDisplayMetadata *)sd->data;
if (metadata->has_luminance)
peak = av_q2d(metadata->max_luminance) / REFERENCE_WHITE;
}
/* smpte2084 needs the side data above to work correctly
* if missing, assume that the original transfer was arib-std-b67 */
if (!peak)
peak = 12;
return peak;
}
static float hable(float in)
{
float a = 0.15f, b = 0.50f, c = 0.10f, d = 0.20f, e = 0.02f, f = 0.30f;
return (in * (in * a + b * c) + d * e) / (in * (in * a + b) + d * f) - e / f;
}
static float mobius(float in, float j, double peak)
{
float a, b;
if (in <= j)
return in;
a = -j * j * (peak - 1.0f) / (j * j - 2.0f * j + peak);
b = (j * j - 2.0f * j * peak + peak) / FFMAX(peak - 1.0f, 1e-6);
return (b * b + 2.0f * b * j + j * j) / (b - a) * (in + a) / (in + b);
}
#define MIX(x,y,a) (x) * (1 - (a)) + (y) * (a)
static void tonemap(TonemapContext *s, AVFrame *out, const AVFrame *in,
const AVPixFmtDescriptor *desc, int x, int y, double peak)
{
const float *r_in = (const float *)(in->data[0] + x * desc->comp[0].step + y * in->linesize[0]);
const float *b_in = (const float *)(in->data[1] + x * desc->comp[1].step + y * in->linesize[1]);
const float *g_in = (const float *)(in->data[2] + x * desc->comp[2].step + y * in->linesize[2]);
float *r_out = (float *)(out->data[0] + x * desc->comp[0].step + y * out->linesize[0]);
float *b_out = (float *)(out->data[1] + x * desc->comp[1].step + y * out->linesize[1]);
float *g_out = (float *)(out->data[2] + x * desc->comp[2].step + y * out->linesize[2]);
float sig, sig_orig;
/* load values */
*r_out = *r_in;
*b_out = *b_in;
*g_out = *g_in;
/* desaturate to prevent unnatural colors */
if (s->desat > 0) {
float luma = s->coeffs->cr * *r_in + s->coeffs->cg * *g_in + s->coeffs->cb * *b_in;
float overbright = FFMAX(luma - s->desat, 1e-6) / FFMAX(luma, 1e-6);
*r_out = MIX(*r_in, luma, overbright);
*g_out = MIX(*g_in, luma, overbright);
*b_out = MIX(*b_in, luma, overbright);
}
/* pick the brightest component, reducing the value range as necessary
* to keep the entire signal in range and preventing discoloration due to
* out-of-bounds clipping */
sig = FFMAX(FFMAX3(*r_out, *g_out, *b_out), 1e-6);
sig_orig = sig;
switch(s->tonemap) {
default:
case TONEMAP_NONE:
// do nothing
break;
case TONEMAP_LINEAR:
sig = sig * s->param / peak;
break;
case TONEMAP_GAMMA:
sig = sig > 0.05f ? pow(sig / peak, 1.0f / s->param)
: sig * pow(0.05f / peak, 1.0f / s->param) / 0.05f;
break;
case TONEMAP_CLIP:
sig = av_clipf(sig * s->param, 0, 1.0f);
break;
case TONEMAP_HABLE:
sig = hable(sig) / hable(peak);
break;
case TONEMAP_REINHARD:
sig = sig / (sig + s->param) * (peak + s->param) / peak;
break;
case TONEMAP_MOBIUS:
sig = mobius(sig, s->param, peak);
break;
}
/* apply the computed scale factor to the color,
* linearly to prevent discoloration */
*r_out *= sig / sig_orig;
*g_out *= sig / sig_orig;
*b_out *= sig / sig_orig;
}
static int filter_frame(AVFilterLink *link, AVFrame *in)
{
TonemapContext *s = link->dst->priv;
AVFilterLink *outlink = link->dst->outputs[0];
AVFrame *out;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
const AVPixFmtDescriptor *odesc = av_pix_fmt_desc_get(outlink->format);
int ret, x, y;
double peak = s->peak;
if (!desc || !odesc) {
av_frame_free(&in);
return AVERROR_BUG;
}
out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
ret = av_frame_copy_props(out, in);
if (ret < 0) {
av_frame_free(&in);
av_frame_free(&out);
return ret;
}
/* input and output transfer will be linear */
if (in->color_trc == AVCOL_TRC_UNSPECIFIED) {
av_log(s, AV_LOG_WARNING, "Untagged transfer, assuming linear light\n");
out->color_trc = AVCOL_TRC_LINEAR;
} else if (in->color_trc != AVCOL_TRC_LINEAR)
av_log(s, AV_LOG_WARNING, "Tonemapping works on linear light only\n");
/* read peak from side data if not passed in */
if (!peak) {
peak = determine_signal_peak(in);
av_log(s, AV_LOG_DEBUG, "Computed signal peak: %f\n", peak);
}
/* load original color space even if pixel format is RGB to compute overbrights */
s->coeffs = &luma_coefficients[in->colorspace];
if (s->desat > 0 && (in->colorspace == AVCOL_SPC_UNSPECIFIED || !s->coeffs)) {
if (in->colorspace == AVCOL_SPC_UNSPECIFIED)
av_log(s, AV_LOG_WARNING, "Missing color space information, ");
else if (!s->coeffs)
av_log(s, AV_LOG_WARNING, "Unsupported color space '%s', ",
av_color_space_name(in->colorspace));
av_log(s, AV_LOG_WARNING, "desaturation is disabled\n");
s->desat = 0;
}
/* do the tone map */
for (y = 0; y < out->height; y++)
for (x = 0; x < out->width; x++)
tonemap(s, out, in, desc, x, y, peak);
/* copy/generate alpha if needed */
if (desc->flags & AV_PIX_FMT_FLAG_ALPHA && odesc->flags & AV_PIX_FMT_FLAG_ALPHA) {
av_image_copy_plane(out->data[3], out->linesize[3],
in->data[3], in->linesize[3],
out->linesize[3], outlink->h);
} else if (odesc->flags & AV_PIX_FMT_FLAG_ALPHA) {
for (y = 0; y < out->height; y++) {
for (x = 0; x < out->width; x++) {
AV_WN32(out->data[3] + x * odesc->comp[3].step + y * out->linesize[3],
av_float2int(1.0f));
}
}
}
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
#define OFFSET(x) offsetof(TonemapContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
static const AVOption tonemap_options[] = {
{ "tonemap", "tonemap algorithm selection", OFFSET(tonemap), AV_OPT_TYPE_INT, {.i64 = TONEMAP_NONE}, TONEMAP_NONE, TONEMAP_MAX - 1, FLAGS, "tonemap" },
{ "none", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_NONE}, 0, 0, FLAGS, "tonemap" },
{ "linear", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_LINEAR}, 0, 0, FLAGS, "tonemap" },
{ "gamma", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_GAMMA}, 0, 0, FLAGS, "tonemap" },
{ "clip", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_CLIP}, 0, 0, FLAGS, "tonemap" },
{ "reinhard", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_REINHARD}, 0, 0, FLAGS, "tonemap" },
{ "hable", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_HABLE}, 0, 0, FLAGS, "tonemap" },
{ "mobius", 0, 0, AV_OPT_TYPE_CONST, {.i64 = TONEMAP_MOBIUS}, 0, 0, FLAGS, "tonemap" },
{ "param", "tonemap parameter", OFFSET(param), AV_OPT_TYPE_DOUBLE, {.dbl = NAN}, DBL_MIN, DBL_MAX, FLAGS },
{ "desat", "desaturation strength", OFFSET(desat), AV_OPT_TYPE_DOUBLE, {.dbl = 2}, 0, DBL_MAX, FLAGS },
{ "peak", "signal peak override", OFFSET(peak), AV_OPT_TYPE_DOUBLE, {.dbl = 0}, 0, DBL_MAX, FLAGS },
{ NULL }
};
static const AVClass tonemap_class = {
.class_name = "tonemap",
.item_name = av_default_item_name,
.option = tonemap_options,
.version = LIBAVUTIL_VERSION_INT,
.category = AV_CLASS_CATEGORY_FILTER,
};
static const AVFilterPad tonemap_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad tonemap_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
AVFilter ff_vf_tonemap = {
.name = "tonemap",
.description = NULL_IF_CONFIG_SMALL("Conversion to/from different dynamic ranges."),
.init = init,
.query_formats = query_formats,
.priv_size = sizeof(TonemapContext),
.priv_class = &tonemap_class,
.inputs = tonemap_inputs,
.outputs = tonemap_outputs,
};