ffmpeg/libavfilter/vf_reverse.c

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/*
* Copyright (c) 2015 Derek Buitenhuis
*
* 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
*/
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#define DEFAULT_LENGTH 300
typedef struct ReverseContext {
int nb_frames;
AVFrame **frames;
unsigned int frames_size;
unsigned int pts_size;
int64_t *pts;
int flush_idx;
} ReverseContext;
static av_cold int init(AVFilterContext *ctx)
{
ReverseContext *s = ctx->priv;
s->pts = av_fast_realloc(NULL, &s->pts_size,
DEFAULT_LENGTH * sizeof(*(s->pts)));
if (!s->pts)
return AVERROR(ENOMEM);
s->frames = av_fast_realloc(NULL, &s->frames_size,
DEFAULT_LENGTH * sizeof(*(s->frames)));
if (!s->frames) {
av_freep(&s->pts);
return AVERROR(ENOMEM);
}
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
ReverseContext *s = ctx->priv;
av_freep(&s->pts);
av_freep(&s->frames);
}
static int config_output(AVFilterLink *outlink)
{
outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
ReverseContext *s = ctx->priv;
if (s->nb_frames + 1 > s->frames_size / sizeof(*(s->frames))) {
void *ptr;
ptr = av_fast_realloc(s->pts, &s->pts_size, s->pts_size * 2);
if (!ptr)
return AVERROR(ENOMEM);
s->pts = ptr;
ptr = av_fast_realloc(s->frames, &s->frames_size, s->frames_size * 2);
if (!ptr)
return AVERROR(ENOMEM);
s->frames = ptr;
}
s->frames[s->nb_frames] = in;
s->pts[s->nb_frames] = in->pts;
s->nb_frames++;
return 0;
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
ReverseContext *s = ctx->priv;
int ret;
ret = ff_request_frame(ctx->inputs[0]);
if (ret == AVERROR_EOF && s->nb_frames > 0) {
AVFrame *out = s->frames[s->nb_frames - 1];
out->pts = s->pts[s->flush_idx++];
ret = ff_filter_frame(outlink, out);
s->nb_frames--;
}
return ret;
}
static const AVFilterPad reverse_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad reverse_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.request_frame = request_frame,
.config_props = config_output,
},
{ NULL }
};
AVFilter ff_vf_reverse = {
.name = "reverse",
.description = NULL_IF_CONFIG_SMALL("Reverse a clip."),
.priv_size = sizeof(ReverseContext),
.init = init,
.uninit = uninit,
.inputs = reverse_inputs,
.outputs = reverse_outputs,
};