102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/*
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* Copyright (c) 2012 Stefano Sabatini
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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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/**
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* @file framestep filter, inspired on libmpcodecs/vf_framestep.c by
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* Daniele Fornighieri <guru AT digitalfantasy it>.
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*/
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#include "libavutil/opt.h"
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#include "avfilter.h"
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#include "internal.h"
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#include "video.h"
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typedef struct {
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const AVClass *class;
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int frame_step;
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} FrameStepContext;
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#define OFFSET(x) offsetof(FrameStepContext, x)
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#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
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static const AVOption framestep_options[] = {
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{ "step", "set frame step", OFFSET(frame_step), AV_OPT_TYPE_INT, {.i64=1}, 1, INT_MAX, FLAGS},
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{NULL},
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};
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AVFILTER_DEFINE_CLASS(framestep);
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static int config_output_props(AVFilterLink *outlink)
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{
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AVFilterContext *ctx = outlink->src;
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FrameStepContext *framestep = ctx->priv;
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AVFilterLink *inlink = ctx->inputs[0];
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outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
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outlink->frame_rate =
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av_div_q(inlink->frame_rate, (AVRational){framestep->frame_step, 1});
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av_log(ctx, AV_LOG_VERBOSE, "step:%d frame_rate:%d/%d(%f) -> frame_rate:%d/%d(%f)\n",
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framestep->frame_step,
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inlink->frame_rate.num, inlink->frame_rate.den, av_q2d(inlink->frame_rate),
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outlink->frame_rate.num, outlink->frame_rate.den, av_q2d(outlink->frame_rate));
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *ref)
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{
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FrameStepContext *framestep = inlink->dst->priv;
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if (!(inlink->frame_count % framestep->frame_step)) {
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return ff_filter_frame(inlink->dst->outputs[0], ref);
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} else {
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av_frame_free(&ref);
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return 0;
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}
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}
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static const AVFilterPad framestep_inputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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.filter_frame = filter_frame,
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},
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{ NULL }
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};
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static const AVFilterPad framestep_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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.config_props = config_output_props,
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},
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{ NULL }
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};
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AVFilter avfilter_vf_framestep = {
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.name = "framestep",
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.description = NULL_IF_CONFIG_SMALL("Select one frame every N frames."),
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.priv_size = sizeof(FrameStepContext),
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.priv_class = &framestep_class,
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.inputs = framestep_inputs,
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.outputs = framestep_outputs,
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.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
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};
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