305 lines
8.9 KiB
C
305 lines
8.9 KiB
C
/*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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
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* a filter enforcing given constant framerate
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*/
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#include <float.h>
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#include "libavutil/common.h"
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#include "libavutil/fifo.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/opt.h"
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#include "libavutil/parseutils.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 FPSContext {
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const AVClass *class;
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AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
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/* timestamps in input timebase */
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int64_t first_pts; ///< pts of the first frame that arrived on this filter
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int64_t pts; ///< pts of the first frame currently in the fifo
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double start_time; ///< pts, in seconds, of the expected first frame
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AVRational framerate; ///< target framerate
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char *fps; ///< a string describing target framerate
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/* statistics */
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int frames_in; ///< number of frames on input
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int frames_out; ///< number of frames on output
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int dup; ///< number of frames duplicated
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int drop; ///< number of framed dropped
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} FPSContext;
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#define OFFSET(x) offsetof(FPSContext, x)
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#define V AV_OPT_FLAG_VIDEO_PARAM
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static const AVOption options[] = {
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{ "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
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{ "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX}, -DBL_MAX, DBL_MAX, V },
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{ NULL },
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};
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static const AVClass class = {
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.class_name = "FPS filter",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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static av_cold int init(AVFilterContext *ctx)
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{
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FPSContext *s = ctx->priv;
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int ret;
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if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
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av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
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return ret;
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}
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if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFrame*))))
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return AVERROR(ENOMEM);
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s->pts = AV_NOPTS_VALUE;
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s->first_pts = AV_NOPTS_VALUE;
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av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
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return 0;
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}
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static void flush_fifo(AVFifoBuffer *fifo)
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{
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while (av_fifo_size(fifo)) {
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AVFrame *tmp;
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av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
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av_frame_free(&tmp);
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}
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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FPSContext *s = ctx->priv;
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if (s->fifo) {
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s->drop += av_fifo_size(s->fifo) / sizeof(AVFilterBufferRef*);
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flush_fifo(s->fifo);
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av_fifo_free(s->fifo);
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}
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av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
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"%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
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}
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static int config_props(AVFilterLink* link)
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{
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FPSContext *s = link->src->priv;
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link->time_base = (AVRational){ s->framerate.den, s->framerate.num };
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link->w = link->src->inputs[0]->w;
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link->h = link->src->inputs[0]->h;
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return 0;
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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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FPSContext *s = ctx->priv;
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int frames_out = s->frames_out;
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int ret = 0;
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while (ret >= 0 && s->frames_out == frames_out)
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ret = ff_request_frame(ctx->inputs[0]);
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/* flush the fifo */
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if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
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int i;
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for (i = 0; av_fifo_size(s->fifo); i++) {
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AVFrame *buf;
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av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
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buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
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outlink->time_base) + s->frames_out;
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if ((ret = ff_filter_frame(outlink, buf)) < 0)
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return ret;
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s->frames_out++;
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}
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return 0;
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}
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return ret;
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}
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static int write_to_fifo(AVFifoBuffer *fifo, AVFrame *buf)
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{
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int ret;
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if (!av_fifo_space(fifo) &&
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(ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {
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av_frame_free(&buf);
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return ret;
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}
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av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
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{
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AVFilterContext *ctx = inlink->dst;
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FPSContext *s = ctx->priv;
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AVFilterLink *outlink = ctx->outputs[0];
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int64_t delta;
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int i, ret;
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s->frames_in++;
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/* discard frames until we get the first timestamp */
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if (s->pts == AV_NOPTS_VALUE) {
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if (buf->pts != AV_NOPTS_VALUE) {
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ret = write_to_fifo(s->fifo, buf);
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if (ret < 0)
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return ret;
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if (s->start_time != DBL_MAX) {
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double first_pts = s->start_time * AV_TIME_BASE;
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first_pts = FFMIN(FFMAX(first_pts, INT64_MIN), INT64_MAX);
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s->first_pts = s->pts = av_rescale_q(first_pts, AV_TIME_BASE_Q,
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inlink->time_base);
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av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64")\n",
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s->first_pts, av_rescale_q(first_pts, AV_TIME_BASE_Q,
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outlink->time_base));
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} else {
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s->first_pts = s->pts = buf->pts;
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}
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} else {
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av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
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"timestamp.\n");
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av_frame_free(&buf);
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s->drop++;
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}
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return 0;
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}
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/* now wait for the next timestamp */
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if (buf->pts == AV_NOPTS_VALUE) {
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return write_to_fifo(s->fifo, buf);
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}
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/* number of output frames */
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delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
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outlink->time_base);
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if (delta < 1) {
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/* drop the frame and everything buffered except the first */
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AVFrame *tmp;
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int drop = av_fifo_size(s->fifo)/sizeof(AVFrame*);
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av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
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s->drop += drop;
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av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
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flush_fifo(s->fifo);
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ret = write_to_fifo(s->fifo, tmp);
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av_frame_free(&buf);
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return ret;
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}
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/* can output >= 1 frames */
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for (i = 0; i < delta; i++) {
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AVFrame *buf_out;
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av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
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/* duplicate the frame if needed */
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if (!av_fifo_size(s->fifo) && i < delta - 1) {
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AVFrame *dup = av_frame_clone(buf_out);
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av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
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if (dup)
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ret = write_to_fifo(s->fifo, dup);
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else
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ret = AVERROR(ENOMEM);
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if (ret < 0) {
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av_frame_free(&buf_out);
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av_frame_free(&buf);
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return ret;
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}
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s->dup++;
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}
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buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
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outlink->time_base) + s->frames_out;
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if ((ret = ff_filter_frame(outlink, buf_out)) < 0) {
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av_frame_free(&buf);
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return ret;
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}
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s->frames_out++;
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}
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flush_fifo(s->fifo);
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ret = write_to_fifo(s->fifo, buf);
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s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
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return ret;
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}
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static const AVFilterPad avfilter_vf_fps_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 avfilter_vf_fps_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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.config_props = config_props
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},
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{ NULL }
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};
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AVFilter ff_vf_fps = {
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.name = "fps",
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.description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
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.init = init,
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.uninit = uninit,
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.priv_size = sizeof(FPSContext),
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.priv_class = &class,
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.inputs = avfilter_vf_fps_inputs,
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.outputs = avfilter_vf_fps_outputs,
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};
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