/* * 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, };