138 lines
3.7 KiB
C
138 lines
3.7 KiB
C
/*
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* Copyright (c) 2015 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 "libavutil/lfg.h"
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#include "libavutil/opt.h"
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#include "libavutil/random_seed.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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#define MAX_FRAMES 512
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typedef struct RandomContext {
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const AVClass *class;
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AVLFG lfg;
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int nb_frames;
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int64_t random_seed;
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int nb_frames_filled;
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AVFrame *frames[MAX_FRAMES];
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int64_t pts[MAX_FRAMES];
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int flush_idx;
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} RandomContext;
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#define OFFSET(x) offsetof(RandomContext, x)
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#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
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static const AVOption random_options[] = {
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{ "frames", "set number of frames in cache", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
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{ "seed", "set the seed", OFFSET(random_seed), AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT32_MAX, FLAGS },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(random);
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static av_cold int init(AVFilterContext *ctx)
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{
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RandomContext *s = ctx->priv;
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uint32_t seed;
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if (s->random_seed < 0)
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s->random_seed = av_get_random_seed();
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seed = s->random_seed;
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av_lfg_init(&s->lfg, seed);
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *in)
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{
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AVFilterContext *ctx = inlink->dst;
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RandomContext *s = ctx->priv;
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AVFilterLink *outlink = ctx->outputs[0];
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AVFrame *out;
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int idx;
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if (s->nb_frames_filled < s->nb_frames) {
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s->frames[s->nb_frames_filled] = in;
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s->pts[s->nb_frames_filled++] = in->pts;
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return 0;
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}
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idx = av_lfg_get(&s->lfg) % s->nb_frames;
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out = s->frames[idx];
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out->pts = s->pts[0];
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memmove(&s->pts[0], &s->pts[1], (s->nb_frames - 1) * sizeof(s->pts[0]));
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s->frames[idx] = in;
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s->pts[s->nb_frames - 1] = in->pts;
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return ff_filter_frame(outlink, out);
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}
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static int request_frame(AVFilterLink *outlink)
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{
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AVFilterContext *ctx = outlink->src;
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RandomContext *s = ctx->priv;
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int ret;
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ret = ff_request_frame(ctx->inputs[0]);
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if (ret == AVERROR_EOF && !ctx->is_disabled && s->nb_frames > 0) {
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AVFrame *out = s->frames[s->nb_frames - 1];
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out->pts = s->pts[s->flush_idx++];
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ret = ff_filter_frame(outlink, out);
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s->frames[s->nb_frames - 1] = NULL;
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s->nb_frames--;
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}
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return ret;
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}
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static const AVFilterPad random_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 random_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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.request_frame = request_frame,
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},
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{ NULL }
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};
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AVFilter ff_vf_random = {
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.name = "random",
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.description = NULL_IF_CONFIG_SMALL("Return random frames."),
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.priv_size = sizeof(RandomContext),
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.priv_class = &random_class,
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.init = init,
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.inputs = random_inputs,
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.outputs = random_outputs,
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};
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