127 lines
3.8 KiB
C
127 lines
3.8 KiB
C
/*
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* Copyright (c) 2021 Paul B Mahol
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <float.h>
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#include "libavutil/opt.h"
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#include "libavutil/imgutils.h"
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#include "avfilter.h"
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#include "formats.h"
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#include "internal.h"
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#include "video.h"
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typedef struct ExposureContext {
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const AVClass *class;
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float exposure;
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float black;
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float scale;
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int (*do_slice)(AVFilterContext *s, void *arg,
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int jobnr, int nb_jobs);
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} ExposureContext;
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static int exposure_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
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{
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ExposureContext *s = ctx->priv;
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AVFrame *frame = arg;
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const int width = frame->width;
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const int height = frame->height;
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const int slice_start = (height * jobnr) / nb_jobs;
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const int slice_end = (height * (jobnr + 1)) / nb_jobs;
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const float black = s->black;
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const float scale = s->scale;
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for (int p = 0; p < 3; p++) {
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const int linesize = frame->linesize[p] / 4;
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float *ptr = (float *)frame->data[p] + slice_start * linesize;
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for (int y = slice_start; y < slice_end; y++) {
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for (int x = 0; x < width; x++)
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ptr[x] = (ptr[x] - black) * scale;
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ptr += linesize;
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}
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}
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
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{
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AVFilterContext *ctx = inlink->dst;
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ExposureContext *s = ctx->priv;
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s->scale = 1.f / (exp2f(-s->exposure) - s->black);
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ff_filter_execute(ctx, s->do_slice, frame, NULL,
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FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));
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return ff_filter_frame(ctx->outputs[0], frame);
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}
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static av_cold int config_input(AVFilterLink *inlink)
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{
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AVFilterContext *ctx = inlink->dst;
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ExposureContext *s = ctx->priv;
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s->do_slice = exposure_slice;
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return 0;
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}
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static const AVFilterPad exposure_inputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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.flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
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.filter_frame = filter_frame,
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.config_props = config_input,
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},
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};
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static const AVFilterPad exposure_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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},
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};
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#define OFFSET(x) offsetof(ExposureContext, x)
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#define VF AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
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static const AVOption exposure_options[] = {
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{ "exposure", "set the exposure correction", OFFSET(exposure), AV_OPT_TYPE_FLOAT, {.dbl=0}, -3, 3, VF },
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{ "black", "set the black level correction", OFFSET(black), AV_OPT_TYPE_FLOAT, {.dbl=0}, -1, 1, VF },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(exposure);
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const AVFilter ff_vf_exposure = {
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.name = "exposure",
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.description = NULL_IF_CONFIG_SMALL("Adjust exposure of the video stream."),
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.priv_size = sizeof(ExposureContext),
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.priv_class = &exposure_class,
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FILTER_INPUTS(exposure_inputs),
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FILTER_OUTPUTS(exposure_outputs),
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FILTER_PIXFMTS(AV_PIX_FMT_GBRPF32, AV_PIX_FMT_GBRAPF32),
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.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
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.process_command = ff_filter_process_command,
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};
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