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ffmpeg / libavfilter / vf_setpts.c @ master

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