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/*
* Copyright (c) 2010 Stefano Sabatini
* Copyright (c) 2008 Victor Paesa
*
* 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
* video presentation timestamp (PTS) modification filter
*/
/* #define DEBUG */
#include "libavutil/eval.h"
#include "libavutil/mathematics.h"
#include "avfilter.h"
#include "internal.h"
#include "video.h"
static const char *const var_names[] = {
"INTERLACED", ///< tell if the current frame is interlaced
"N", ///< frame number (starting at zero)
"POS", ///< original position in the file of the frame
"PREV_INPTS", ///< previous input PTS
"PREV_OUTPTS", ///< previous output PTS
"PTS", ///< original pts in the file of the frame
"STARTPTS", ///< PTS at start of movie
"TB", ///< timebase
NULL
};
enum var_name {
VAR_INTERLACED,
VAR_N,
VAR_POS,
VAR_PREV_INPTS,
VAR_PREV_OUTPTS,
VAR_PTS,
VAR_STARTPTS,
VAR_TB,
VAR_VARS_NB
};
typedef struct {
AVExpr *expr;
double var_values[VAR_VARS_NB];
} SetPTSContext;
static av_cold int init(AVFilterContext *ctx, const char *args)
{
SetPTSContext *setpts = ctx->priv;
int ret;
if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
return ret;
}
setpts->var_values[VAR_N ] = 0.0;
setpts->var_values[VAR_PREV_INPTS ] = NAN;
setpts->var_values[VAR_PREV_OUTPTS] = NAN;
setpts->var_values[VAR_STARTPTS ] = NAN;
return 0;
}
static int config_input(AVFilterLink *inlink)
{
SetPTSContext *setpts = inlink->dst->priv;
setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
av_log(inlink->src, AV_LOG_VERBOSE, "TB:%f\n", setpts->var_values[VAR_TB]);
return 0;
}
#define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
#define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
{
SetPTSContext *setpts = inlink->dst->priv;
double d;
AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
if (!outpicref)
return AVERROR(ENOMEM);
if (isnan(setpts->var_values[VAR_STARTPTS]))
setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
setpts->var_values[VAR_PTS ] = TS2D(inpicref->pts);
setpts->var_values[VAR_POS ] = inpicref->pos == -1 ? NAN : inpicref->pos;
d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
outpicref->pts = D2TS(d);
#ifdef DEBUG
av_log(inlink->dst, AV_LOG_DEBUG,
"n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
(int64_t)setpts->var_values[VAR_N],
(int)setpts->var_values[VAR_INTERLACED],
inpicref ->pos,
inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
#endif
setpts->var_values[VAR_N] += 1.0;
setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
return ff_start_frame(inlink->dst->outputs[0], outpicref);
}
static av_cold void uninit(AVFilterContext *ctx)
{
SetPTSContext *setpts = ctx->priv;
av_expr_free(setpts->expr);
setpts->expr = NULL;
}
AVFilter avfilter_vf_setpts = {
.name = "setpts",
.description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
.init = init,
.uninit = uninit,
.priv_size = sizeof(SetPTSContext),
.inputs = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.get_video_buffer = ff_null_get_video_buffer,
.config_props = config_input,
.start_frame = start_frame, },
{ .name = NULL }},
.outputs = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO, },
{ .name = NULL}},
};
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