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/*
* Copyright 2007 Bobby Bingham
* Copyright 2012 Robert Nagy <ronag89 gmail com>
* Copyright 2012 Anton Khirnov <anton khirnov net>
*
* 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
* a filter enforcing given constant framerate
*/
#include "libavutil/fifo.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "avfilter.h"
#include "internal.h"
#include "video.h"
typedef struct FPSContext {
const AVClass *class;
AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
/* timestamps in input timebase */
int64_t first_pts; ///< pts of the first frame that arrived on this filter
int64_t pts; ///< pts of the first frame currently in the fifo
AVRational framerate; ///< target framerate
char *fps; ///< a string describing target framerate
/* statistics */
int frames_in; ///< number of frames on input
int frames_out; ///< number of frames on output
int dup; ///< number of frames duplicated
int drop; ///< number of framed dropped
} FPSContext;
#define OFFSET(x) offsetof(FPSContext, x)
#define V AV_OPT_FLAG_VIDEO_PARAM
static const AVOption fps_options[] = {
{ "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
{ NULL },
};
AVFILTER_DEFINE_CLASS(fps);
static av_cold int init(AVFilterContext *ctx, const char *args)
{
FPSContext *s = ctx->priv;
int ret;
s->class = &fps_class;
av_opt_set_defaults(s);
if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
args);
return ret;
}
if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
return ret;
}
av_opt_free(s);
if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
return AVERROR(ENOMEM);
av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
return 0;
}
static void flush_fifo(AVFifoBuffer *fifo)
{
while (av_fifo_size(fifo)) {
AVFilterBufferRef *tmp;
av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
avfilter_unref_buffer(tmp);
}
}
static av_cold void uninit(AVFilterContext *ctx)
{
FPSContext *s = ctx->priv;
if (s->fifo) {
flush_fifo(s->fifo);
av_fifo_free(s->fifo);
}
av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
"%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
}
static int config_props(AVFilterLink* link)
{
FPSContext *s = link->src->priv;
link->time_base = av_inv_q(s->framerate);
link->frame_rate= s->framerate;
link->w = link->src->inputs[0]->w;
link->h = link->src->inputs[0]->h;
s->pts = AV_NOPTS_VALUE;
return 0;
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
FPSContext *s = ctx->priv;
int frames_out = s->frames_out;
int ret = 0;
while (ret >= 0 && s->frames_out == frames_out)
ret = ff_request_frame(ctx->inputs[0]);
/* flush the fifo */
if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
int i;
for (i = 0; av_fifo_size(s->fifo); i++) {
AVFilterBufferRef *buf;
av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
outlink->time_base) + s->frames_out;
if ((ret = ff_start_frame(outlink, buf)) < 0 ||
(ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
(ret = ff_end_frame(outlink)) < 0)
return ret;
s->frames_out++;
}
return 0;
}
return ret;
}
static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
{
int ret;
if (!av_fifo_space(fifo) &&
(ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {
avfilter_unref_bufferp(&buf);
return ret;
}
av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
return 0;
}
static int end_frame(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
FPSContext *s = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
AVFilterBufferRef *buf = inlink->cur_buf;
int64_t delta;
int i, ret;
inlink->cur_buf = NULL;
s->frames_in++;
/* discard frames until we get the first timestamp */
if (s->pts == AV_NOPTS_VALUE) {
if (buf->pts != AV_NOPTS_VALUE) {
ret = write_to_fifo(s->fifo, buf);
if (ret < 0)
return ret;
s->first_pts = s->pts = buf->pts;
} else {
av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
"timestamp.\n");
avfilter_unref_buffer(buf);
s->drop++;
}
return 0;
}
/* now wait for the next timestamp */
if (buf->pts == AV_NOPTS_VALUE) {
return write_to_fifo(s->fifo, buf);
}
/* number of output frames */
delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
outlink->time_base);
if (delta < 1) {
/* drop the frame and everything buffered except the first */
AVFilterBufferRef *tmp;
int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);
av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
s->drop += drop;
av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
flush_fifo(s->fifo);
ret = write_to_fifo(s->fifo, tmp);
avfilter_unref_buffer(buf);
return ret;
}
/* can output >= 1 frames */
for (i = 0; i < delta; i++) {
AVFilterBufferRef *buf_out;
av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
/* duplicate the frame if needed */
if (!av_fifo_size(s->fifo) && i < delta - 1) {
AVFilterBufferRef *dup = avfilter_ref_buffer(buf_out, AV_PERM_READ);
av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
if (dup)
ret = write_to_fifo(s->fifo, dup);
else
ret = AVERROR(ENOMEM);
if (ret < 0) {
avfilter_unref_bufferp(&buf_out);
avfilter_unref_bufferp(&buf);
return ret;
}
s->dup++;
}
buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
outlink->time_base) + s->frames_out;
if ((ret = ff_start_frame(outlink, buf_out)) < 0 ||
(ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
(ret = ff_end_frame(outlink)) < 0) {
avfilter_unref_bufferp(&buf);
return ret;
}
s->frames_out++;
}
flush_fifo(s->fifo);
ret = write_to_fifo(s->fifo, buf);
s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
return ret;
}
static int null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)
{
return 0;
}
static int null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
{
return 0;
}
AVFilter avfilter_vf_fps = {
.name = "fps",
.description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
.init = init,
.uninit = uninit,
.priv_size = sizeof(FPSContext),
.inputs = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.start_frame = null_start_frame,
.draw_slice = null_draw_slice,
.end_frame = end_frame, },
{ .name = NULL}},
.outputs = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.request_frame = request_frame,
.config_props = config_props},
{ .name = NULL}},
};
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