From f563ee1ad93511dfe7dd252578d7801e0cbbe968 Mon Sep 17 00:00:00 2001 From: Sarthak Indurkhya Date: Sat, 5 Jul 2025 22:33:46 +0530 Subject: [PATCH] avfilter: add inversetonemap filter This filter performs inverse tone mapping from SDR to HDR using local adaptation and PQ mapping. - Added inversetonemap video filter for SDR to HDR conversion. --- Changelog | 1 + libavfilter/Makefile | 1 + libavfilter/allfilters.c | 1 + libavfilter/vf_inversetonemap.c | 98 ++++++++++++++++----------------- 4 files changed, 51 insertions(+), 50 deletions(-) diff --git a/Changelog b/Changelog index 81e2cc813f..0aecf6dbf1 100644 --- a/Changelog +++ b/Changelog @@ -2,6 +2,7 @@ Entries are sorted chronologically from oldest to youngest within each release, releases are sorted from youngest to oldest. version : +- Added inversetonemap video filter for SDR to HDR conversion. - yasm support dropped, users need to use nasm - VVC VAAPI decoder - RealVideo 6.0 decoder diff --git a/libavfilter/Makefile b/libavfilter/Makefile index 97f8f17272..e715a3a5e4 100644 --- a/libavfilter/Makefile +++ b/libavfilter/Makefile @@ -191,6 +191,7 @@ OBJS-$(CONFIG_SINE_FILTER) += asrc_sine.o OBJS-$(CONFIG_ANULLSINK_FILTER) += asink_anullsink.o # video filters +OBJS-$(CONFIG_INVERSETONEMAP_FILTER) += vf_inversetonemap.o OBJS-$(CONFIG_ADDROI_FILTER) += vf_addroi.o OBJS-$(CONFIG_ALPHAEXTRACT_FILTER) += vf_extractplanes.o OBJS-$(CONFIG_ALPHAMERGE_FILTER) += vf_alphamerge.o framesync.o diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c index 3bc045b28f..2f67300ca1 100644 --- a/libavfilter/allfilters.c +++ b/libavfilter/allfilters.c @@ -176,6 +176,7 @@ extern const FFFilter ff_asrc_sine; extern const FFFilter ff_asink_anullsink; +extern const FFFilter ff_vf_inversetonemap; extern const FFFilter ff_vf_addroi; extern const FFFilter ff_vf_alphaextract; extern const FFFilter ff_vf_alphamerge; diff --git a/libavfilter/vf_inversetonemap.c b/libavfilter/vf_inversetonemap.c index 28ea1ef29e..d8d8920151 100644 --- a/libavfilter/vf_inversetonemap.c +++ b/libavfilter/vf_inversetonemap.c @@ -1,3 +1,22 @@ +/* + * Copyright (c) 2025 Sarthak Indurkhya + * 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 * @brief SDR to HDR inverse tone mapping filter for FFmpeg @@ -38,7 +57,7 @@ typedef struct FilterContext { float HDR_max; } FilterContext; -//declaring lookup table + static float bt709_gamma_lut[256]; static void init_bt709_gamma_lut(void) { @@ -51,14 +70,13 @@ static void init_bt709_gamma_lut(void) { } } -// Rec.709 to Rec.2020 matrix + static const float bt709_to_bt2020[3][3] = { {0.6274f, 0.3293f, 0.0433f}, {0.0691f, 0.9195f, 0.0114f}, {0.0164f, 0.0880f, 0.8956f} }; -// PQ transfer function #define PQ_M1 0.1593017578125f #define PQ_M2 78.84375f #define PQ_C1 0.8359375f @@ -80,12 +98,10 @@ static void compute_local_adaptation(const float *R_full, float *sigma, int widt float *temp_blur = av_mallocz(npix * sizeof(float)); float *spatial_weights = av_malloc((2 * radius + 1) * sizeof(float)); - // 1D Gaussian kernel for separable blur for (int i = -radius; i <= radius; i++) { spatial_weights[i + radius] = expf(-(i * i) / (2 * sigma_spatial * sigma_spatial)); } - // Scene max luminance float scene_max = 1e-6f; for (int i = 0; i < npix; i++) { if (R_full[i] > scene_max) @@ -93,7 +109,6 @@ static void compute_local_adaptation(const float *R_full, float *sigma, int widt } float hdr_scale = HDR_max / scene_max; - // ---- Horizontal blur pass ---- for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) { float sum = 0.0f, sum_weights = 0.0f; @@ -113,7 +128,6 @@ static void compute_local_adaptation(const float *R_full, float *sigma, int widt } } - // ---- Vertical blur pass ---- for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) { float sum = 0.0f, sum_weights = 0.0f; @@ -137,18 +151,15 @@ static void compute_local_adaptation(const float *R_full, float *sigma, int widt av_free(spatial_weights); } static void compute_local_adaptation_fast(const float *R_full, float *sigma, int width, int height, - float sigma_spatial, float sigma_range, float HDR_max) -{ + float sigma_spatial, float sigma_range, float HDR_max){ const int scale = 4; int down_w = width / scale; int down_h = height / scale; int npix_small = down_w * down_h; - // Allocating downsampled and result buffers float *R_small = av_malloc(npix_small * sizeof(float)); float *sigma_small = av_malloc(npix_small * sizeof(float)); - // Simple box downsampling for (int y = 0; y < down_h; y++) { for (int x = 0; x < down_w; x++) { float sum = 0.0f; @@ -167,7 +178,6 @@ static void compute_local_adaptation_fast(const float *R_full, float *sigma, int compute_local_adaptation(R_small, sigma_small, down_w, down_h, sigma_spatial, sigma_range, HDR_max); - // Upsampling sigma_small -> sigma struct SwsContext *sws_ctx = sws_getContext(down_w, down_h, AV_PIX_FMT_GRAYF32, width, height, AV_PIX_FMT_GRAYF32, SWS_BILINEAR, NULL, NULL, NULL); @@ -199,14 +209,12 @@ static void compute_hdr_intensity(const float *R_full, const float *sigma, float static void inverse_tone_map_linear_rgb( const float *R, const float *G, const float *B, float *R_hdr, float *G_hdr, float *B_hdr, - int width, int height, FilterContext *s) -{ + int width, int height, FilterContext *s){ int npix = width * height; float *Y = av_malloc(npix * sizeof(float)); float *Y_sigma = av_malloc(npix * sizeof(float)); float *Y_hdr = av_malloc(npix * sizeof(float)); - // Computing luminance (BT.2020) for (int i = 0; i < npix; i++) Y[i] = 0.2627f * R[i] + 0.6780f * G[i] + 0.0593f * B[i]; @@ -215,7 +223,6 @@ static void inverse_tone_map_linear_rgb( compute_hdr_intensity(Y, Y_sigma, Y_hdr, width, height, s->n, 1.0f); - // Scaling RGB channels for (int i = 0; i < npix; i++) { float scale = Y_hdr[i] / (Y[i] + 1e-6f); R_hdr[i] = R[i] * scale; @@ -249,11 +256,20 @@ static void dither_pq_to_10bit(const float *pq, uint16_t *y_temp, int width, int } static int fil_func(AVFilterLink *inlink, AVFrame *in) { + const float exposure = 3.5f; + const float contrast = 1.02f; + const float black = 0.03f; + const float white = 8.0f; + const float s_curve_pow = 1.00f; + const float white_balance_r = 1.0f; + const float white_balance_g = 1.0f; + const float white_balance_b = 1.1f; + AVFilterContext *ctx = inlink->dst; FilterContext *s = ctx->priv; int width = in->width, height = in->height, npix = width * height; - // Converting to RGB24 + struct SwsContext *sws_ctx = sws_getContext( width, height, in->format, width, height, AV_PIX_FMT_RGB24, @@ -272,9 +288,6 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { rgb_frame->data, rgb_frame->linesize); sws_freeContext(sws_ctx); - //Calling gamma lookup table initialization - init_bt709_gamma_lut(); - // Gamma linearization & gamut mapping float *R = av_malloc(npix * sizeof(float)); float *G = av_malloc(npix * sizeof(float)); float *B = av_malloc(npix * sizeof(float)); @@ -290,20 +303,21 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { } } - // Inverse Tone Mapping float *R_hdr = av_malloc(npix * sizeof(float)); float *G_hdr = av_malloc(npix * sizeof(float)); float *B_hdr = av_malloc(npix * sizeof(float)); inverse_tone_map_linear_rgb(R, G, B, R_hdr, G_hdr, B_hdr, width, height, s); - float exposure = 3.5f; //4.0 - float contrast = 1.02f; //1.10 - float black = 0.03f, white = 8.0f; //0.04 //12.0 - float s_curve_pow = 1.00f; //0.70 + /* + float exposure = 3.5f; //4.0 + float contrast = 1.02f; //1.10 + float black = 0.03f, white = 8.0f; //0.04 //12.0 + float s_curve_pow = 1.00f; //0.70 + */ for (int i = 0; i < npix; i++) { - float r = R[i] * exposure, g = G[i] * exposure, b = B[i] * exposure; + float r = R_hdr[i] * exposure, g = G_hdr[i] * exposure, b = B_hdr[i] * exposure; float lum = 0.2627f * r + 0.6780f * g + 0.0593f * b; @@ -316,21 +330,14 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { g *= scale; b *= scale; - // Contrast r = (r - 0.5f) * contrast + 0.5f; g = (g - 0.5f) * contrast + 0.5f; b = (b - 0.5f) * contrast + 0.5f; - // White balance correction - float white_balance_r = 1.0f; - float white_balance_g = 1.0f; - float white_balance_b = 1.1f; - r *= white_balance_r; g *= white_balance_g; b *= white_balance_b; - // Final clamp r = fminf(fmaxf(r, 0.0f), 1.0f); g = fminf(fmaxf(g, 0.0f), 1.0f); b = fminf(fmaxf(b, 0.0f), 1.0f); @@ -340,18 +347,16 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { B_hdr[i] = b; } - //Computing linear luminance (BT.2020) float *Y = av_malloc(npix * sizeof(float)); for (int i = 0; i < npix; i++) Y[i] = 0.2627f * R_hdr[i] + 0.6780f * G_hdr[i] + 0.0593f * B_hdr[i]; - // Applying PQ transfer float *pq = av_malloc(npix * sizeof(float)); for (int i = 0; i < npix; i++) { pq[i] = linear_to_pq(Y[i] * (10000.0f / s->HDR_max)); pq[i] = fminf(fmaxf(pq[i], 0.0f), 1.0f); } - //Allocating output frame (YUV420P10LE) + AVFrame *out = av_frame_alloc(); out->format = AV_PIX_FMT_YUV420P10LE; out->width = width; @@ -359,25 +364,21 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { av_frame_get_buffer(out, 32); av_frame_copy_props(out, in); - // Setting HDR metadata + out->color_primaries = AVCOL_PRI_BT2020; - out->color_trc = AVCOL_TRC_SMPTE2084; // PQ + out->color_trc = AVCOL_TRC_SMPTE2084; out->colorspace = AVCOL_SPC_BT2020_NCL; - out->color_range = AVCOL_RANGE_MPEG; // Full range for HDR + out->color_range = AVCOL_RANGE_MPEG; - // Setting mastering display metadata if available if (out->metadata) { - // Mastering display primaries (BT.2020) av_dict_set(&out->metadata, "mastering_display_primaries", "0.708,0.292,0.170,0.797,0.131,0.046,0.3127,0.3290", 0); - // Mastering display luminance (in nits) char luminance_str[64]; snprintf(luminance_str, sizeof(luminance_str), "%.1f,%.1f", - s->HDR_max, 0.001f); // Max luminance, min luminance + s->HDR_max, 0.001f); av_dict_set(&out->metadata, "mastering_display_luminance", luminance_str, 0); - // Content light level char content_light_str[64]; float max_content_light = 0.0f; for (int i = 0; i < npix; i++) { @@ -389,12 +390,10 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { av_dict_set(&out->metadata, "content_light_level", content_light_str, 0); } - // Clearing Y, U, V planes av_frame_make_writable(out); for (int y = 0; y < height; y++) memset(out->data[0] + y * out->linesize[0], 0, out->linesize[0]); - // Dithering PQ to 10-bit Y plane uint16_t *y_temp = av_malloc(npix * sizeof(uint16_t)); dither_pq_to_10bit(pq, y_temp, width, height); for (int y = 0; y < height; y++) { @@ -402,7 +401,6 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { memcpy(row, y_temp + y * width, width * sizeof(uint16_t)); } - // Computing and encoding U, V chroma planes from original SDR RGB for (int y = 0; y < height / 2; y++) { uint16_t *u_row = (uint16_t *)(out->data[1] + y * out->linesize[1]); uint16_t *v_row = (uint16_t *)(out->data[2] + y * out->linesize[2]); @@ -425,8 +423,8 @@ static int fil_func(AVFilterLink *inlink, AVFrame *in) { float U = (b - Y_sdr) / 1.8814f; float V = (r - Y_sdr) / 1.4746f; float chroma_blend = 1.0f - fminf(Y_sdr, 1.0f); - float chroma_boost = 0.85f * chroma_blend + 0.85f * (1.0f - chroma_blend); //0.8 - // float chroma_boost = 1.08f; + float chroma_boost = 0.85f * chroma_blend + 0.85f * (1.0f - chroma_blend); + U *= chroma_boost; V *= chroma_boost; U = fmaxf(fminf(U, 0.45f), -0.45f); @@ -471,7 +469,7 @@ static const AVFilterPad fil_outputs[] = { }; static int ff_filter_init(AVFilterContext *avctx) { - av_log_set_level(AV_LOG_DEBUG); + init_bt709_gamma_lut(); av_log(avctx, AV_LOG_INFO, "Initializing filter with 1 input and 1 output\n"); return 0; } -- 2.49.0