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b9c928a486
This flag allows distinguishing between filters that actually modify the data and those that only modify metadata or gather some stream information.
395 lines
14 KiB
C
395 lines
14 KiB
C
/*
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* Copyright 2007 Bobby Bingham
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* Copyright 2012 Robert Nagy <ronag89 gmail com>
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* Copyright 2012 Anton Khirnov <anton khirnov net>
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* Copyright 2018 Calvin Walton <calvin.walton@kepstin.ca>
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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
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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 <stdint.h>
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#include "libavutil/avassert.h"
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#include "libavutil/eval.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/opt.h"
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#include "avfilter.h"
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#include "filters.h"
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#include "internal.h"
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enum EOFAction {
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EOF_ACTION_ROUND,
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EOF_ACTION_PASS,
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EOF_ACTION_NB
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};
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static const char *const var_names[] = {
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"source_fps",
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"ntsc",
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"pal",
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"film",
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"ntsc_film",
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NULL
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};
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enum var_name {
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VAR_SOURCE_FPS,
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VAR_FPS_NTSC,
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VAR_FPS_PAL,
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VAR_FPS_FILM,
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VAR_FPS_NTSC_FILM,
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VARS_NB
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};
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static const double ntsc_fps = 30000.0 / 1001.0;
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static const double pal_fps = 25.0;
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static const double film_fps = 24.0;
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static const double ntsc_film_fps = 24000.0 / 1001.0;
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typedef struct FPSContext {
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const AVClass *class;
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double start_time; ///< pts, in seconds, of the expected first frame
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char *framerate; ///< expression that defines the target framerate
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int rounding; ///< AVRounding method for timestamps
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int eof_action; ///< action performed for last frame in FIFO
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/* Set during outlink configuration */
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int64_t in_pts_off; ///< input frame pts offset for start_time handling
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int64_t out_pts_off; ///< output frame pts offset for start_time handling
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/* Runtime state */
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int status; ///< buffered input status
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int64_t status_pts; ///< buffered input status timestamp
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AVFrame *frames[2]; ///< buffered frames
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int frames_count; ///< number of buffered frames
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int64_t next_pts; ///< pts of the next frame to output
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/* statistics */
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int cur_frame_out; ///< number of times current frame has been output
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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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#define F AV_OPT_FLAG_FILTERING_PARAM
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static const AVOption fps_options[] = {
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{ "fps", "A string describing desired output framerate", OFFSET(framerate), AV_OPT_TYPE_STRING, { .str = "25" }, 0, 0, V|F },
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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|F },
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{ "round", "set rounding method for timestamps", OFFSET(rounding), AV_OPT_TYPE_INT, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },
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{ "zero", "round towards 0", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_ZERO }, 0, 0, V|F, "round" },
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{ "inf", "round away from 0", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_INF }, 0, 0, V|F, "round" },
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{ "down", "round towards -infty", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_DOWN }, 0, 0, V|F, "round" },
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{ "up", "round towards +infty", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_UP }, 0, 0, V|F, "round" },
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{ "near", "round to nearest", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_NEAR_INF }, 0, 0, V|F, "round" },
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{ "eof_action", "action performed for last frame", OFFSET(eof_action), AV_OPT_TYPE_INT, { .i64 = EOF_ACTION_ROUND }, 0, EOF_ACTION_NB-1, V|F, "eof_action" },
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{ "round", "round similar to other frames", 0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_ROUND }, 0, 0, V|F, "eof_action" },
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{ "pass", "pass through last frame", 0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_PASS }, 0, 0, V|F, "eof_action" },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(fps);
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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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s->status_pts = AV_NOPTS_VALUE;
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s->next_pts = AV_NOPTS_VALUE;
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return 0;
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}
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/* Remove the first frame from the buffer, returning it */
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static AVFrame *shift_frame(AVFilterContext *ctx, FPSContext *s)
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{
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AVFrame *frame;
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/* Must only be called when there are frames in the buffer */
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av_assert1(s->frames_count > 0);
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frame = s->frames[0];
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s->frames[0] = s->frames[1];
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s->frames[1] = NULL;
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s->frames_count--;
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/* Update statistics counters */
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s->frames_out += s->cur_frame_out;
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if (s->cur_frame_out > 1) {
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av_log(ctx, AV_LOG_DEBUG, "Duplicated frame with pts %"PRId64" %d times\n",
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frame->pts, s->cur_frame_out - 1);
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s->dup += s->cur_frame_out - 1;
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} else if (s->cur_frame_out == 0) {
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av_log(ctx, AV_LOG_DEBUG, "Dropping frame with pts %"PRId64"\n",
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frame->pts);
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s->drop++;
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}
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s->cur_frame_out = 0;
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return frame;
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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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AVFrame *frame;
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while (s->frames_count > 0) {
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frame = shift_frame(ctx, s);
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av_frame_free(&frame);
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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* outlink)
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{
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AVFilterContext *ctx = outlink->src;
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AVFilterLink *inlink = ctx->inputs[0];
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FPSContext *s = ctx->priv;
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double var_values[VARS_NB], res;
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int ret;
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var_values[VAR_SOURCE_FPS] = av_q2d(inlink->frame_rate);
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var_values[VAR_FPS_NTSC] = ntsc_fps;
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var_values[VAR_FPS_PAL] = pal_fps;
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var_values[VAR_FPS_FILM] = film_fps;
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var_values[VAR_FPS_NTSC_FILM] = ntsc_film_fps;
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ret = av_expr_parse_and_eval(&res, s->framerate,
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var_names, var_values,
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NULL, NULL, NULL, NULL, NULL, 0, ctx);
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if (ret < 0)
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return ret;
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outlink->frame_rate = av_d2q(res, INT_MAX);
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outlink->time_base = av_inv_q(outlink->frame_rate);
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/* Calculate the input and output pts offsets for start_time */
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if (s->start_time != DBL_MAX && s->start_time != AV_NOPTS_VALUE) {
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double first_pts = s->start_time * AV_TIME_BASE;
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if (first_pts < INT64_MIN || first_pts > INT64_MAX) {
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av_log(ctx, AV_LOG_ERROR, "Start time %f cannot be represented in internal time base\n",
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s->start_time);
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return AVERROR(EINVAL);
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}
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s->in_pts_off = av_rescale_q_rnd(first_pts, AV_TIME_BASE_Q, inlink->time_base,
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s->rounding | AV_ROUND_PASS_MINMAX);
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s->out_pts_off = av_rescale_q_rnd(first_pts, AV_TIME_BASE_Q, outlink->time_base,
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s->rounding | AV_ROUND_PASS_MINMAX);
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s->next_pts = s->out_pts_off;
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av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64") from start time %f\n",
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s->in_pts_off, s->out_pts_off, s->start_time);
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}
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av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", outlink->frame_rate.num, outlink->frame_rate.den);
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return 0;
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}
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/* Read a frame from the input and save it in the buffer */
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static int read_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink)
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{
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AVFrame *frame;
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int ret;
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int64_t in_pts;
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/* Must only be called when we have buffer room available */
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av_assert1(s->frames_count < 2);
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ret = ff_inlink_consume_frame(inlink, &frame);
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/* Caller must have run ff_inlink_check_available_frame first */
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av_assert1(ret);
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if (ret < 0)
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return ret;
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/* Convert frame pts to output timebase.
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* The dance with offsets is required to match the rounding behaviour of the
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* previous version of the fps filter when using the start_time option. */
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in_pts = frame->pts;
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frame->pts = s->out_pts_off + av_rescale_q_rnd(in_pts - s->in_pts_off,
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inlink->time_base, outlink->time_base,
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s->rounding | AV_ROUND_PASS_MINMAX);
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av_log(ctx, AV_LOG_DEBUG, "Read frame with in pts %"PRId64", out pts %"PRId64"\n",
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in_pts, frame->pts);
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s->frames[s->frames_count++] = frame;
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s->frames_in++;
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return 1;
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}
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/* Write a frame to the output */
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static int write_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *outlink, int *again)
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{
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AVFrame *frame;
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av_assert1(s->frames_count == 2 || (s->status && s->frames_count == 1));
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/* We haven't yet determined the pts of the first frame */
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if (s->next_pts == AV_NOPTS_VALUE) {
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if (s->frames[0]->pts != AV_NOPTS_VALUE) {
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s->next_pts = s->frames[0]->pts;
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av_log(ctx, AV_LOG_VERBOSE, "Set first pts to %"PRId64"\n", s->next_pts);
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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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frame = shift_frame(ctx, s);
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av_frame_free(&frame);
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*again = 1;
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return 0;
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}
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}
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/* There are two conditions where we want to drop a frame:
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* - If we have two buffered frames and the second frame is acceptable
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* as the next output frame, then drop the first buffered frame.
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* - If we have status (EOF) set, drop frames when we hit the
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* status timestamp. */
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if ((s->frames_count == 2 && s->frames[1]->pts <= s->next_pts) ||
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(s->status && s->status_pts <= s->next_pts)) {
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frame = shift_frame(ctx, s);
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av_frame_free(&frame);
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*again = 1;
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return 0;
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/* Output a copy of the first buffered frame */
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} else {
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frame = av_frame_clone(s->frames[0]);
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if (!frame)
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return AVERROR(ENOMEM);
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// Make sure Closed Captions will not be duplicated
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av_frame_remove_side_data(s->frames[0], AV_FRAME_DATA_A53_CC);
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frame->pts = s->next_pts++;
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av_log(ctx, AV_LOG_DEBUG, "Writing frame with pts %"PRId64" to pts %"PRId64"\n",
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s->frames[0]->pts, frame->pts);
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s->cur_frame_out++;
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*again = 1;
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return ff_filter_frame(outlink, frame);
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}
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}
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/* Convert status_pts to outlink timebase */
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static void update_eof_pts(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink, int64_t status_pts)
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{
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int eof_rounding = (s->eof_action == EOF_ACTION_PASS) ? AV_ROUND_UP : s->rounding;
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s->status_pts = av_rescale_q_rnd(status_pts, inlink->time_base, outlink->time_base,
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eof_rounding | AV_ROUND_PASS_MINMAX);
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av_log(ctx, AV_LOG_DEBUG, "EOF is at pts %"PRId64"\n", s->status_pts);
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}
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static int activate(AVFilterContext *ctx)
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{
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FPSContext *s = ctx->priv;
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AVFilterLink *inlink = ctx->inputs[0];
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AVFilterLink *outlink = ctx->outputs[0];
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int ret;
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int again = 0;
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int64_t status_pts;
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FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
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/* No buffered status: normal operation */
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if (!s->status) {
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/* Read available input frames if we have room */
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while (s->frames_count < 2 && ff_inlink_check_available_frame(inlink)) {
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ret = read_frame(ctx, s, inlink, outlink);
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if (ret < 0)
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return ret;
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}
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/* We do not yet have enough frames to produce output */
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if (s->frames_count < 2) {
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/* Check if we've hit EOF (or otherwise that an error status is set) */
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ret = ff_inlink_acknowledge_status(inlink, &s->status, &status_pts);
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if (ret > 0)
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update_eof_pts(ctx, s, inlink, outlink, status_pts);
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if (!ret) {
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/* If someone wants us to output, we'd better ask for more input */
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FF_FILTER_FORWARD_WANTED(outlink, inlink);
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return 0;
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}
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}
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}
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/* Buffered frames are available, so generate an output frame */
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if (s->frames_count > 0) {
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ret = write_frame(ctx, s, outlink, &again);
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/* Couldn't generate a frame, so schedule us to perform another step */
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if (again)
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ff_filter_set_ready(ctx, 100);
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return ret;
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}
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/* No frames left, so forward the status */
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if (s->status && s->frames_count == 0) {
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ff_outlink_set_status(outlink, s->status, s->next_pts);
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return 0;
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}
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return FFERROR_NOT_READY;
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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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},
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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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.config_props = config_props,
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},
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};
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const 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 = &fps_class,
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.activate = activate,
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.flags = AVFILTER_FLAG_METADATA_ONLY,
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FILTER_INPUTS(avfilter_vf_fps_inputs),
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FILTER_OUTPUTS(avfilter_vf_fps_outputs),
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};
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