libavfilter/vf_setpts.c

   1 /*
   2  * Copyright (c) 2010 Stefano Sabatini
   3  * Copyright (c) 2008 Victor Paesa
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * video presentation timestamp (PTS) modification filter
  25  */
  26
  27 /* #define DEBUG */
  28
  29 #include "libavutil/eval.h"
  30 #include "libavutil/internal.h"
  31 #include "libavutil/mathematics.h"
  32 #include "libavutil/time.h"
  33 #include "avfilter.h"
  34 #include "internal.h"
  35 #include "video.h"
  36
  37 static const char *const var_names[] = {
  38     "E",           ///< Euler number
  39     "INTERLACED",  ///< tell if the current frame is interlaced
  40     "N",           ///< frame number (starting at zero)
  41     "PHI",         ///< golden ratio
  42     "PI",          ///< greek pi
  43     "POS",         ///< original position in the file of the frame
  44     "PREV_INPTS",  ///< previous  input PTS
  45     "PREV_OUTPTS", ///< previous output PTS
  46     "PTS",         ///< original pts in the file of the frame
  47     "STARTPTS",   ///< PTS at start of movie
  48     "TB",          ///< timebase
  49     "RTCTIME",     ///< wallclock (RTC) time in micro seconds
  50     "RTCSTART",    ///< wallclock (RTC) time at the start of the movie in micro seconds
  51     NULL
  52 };
  53
  54 enum var_name {
  55     VAR_E,
  56     VAR_INTERLACED,
  57     VAR_N,
  58     VAR_PHI,
  59     VAR_PI,
  60     VAR_POS,
  61     VAR_PREV_INPTS,
  62     VAR_PREV_OUTPTS,
  63     VAR_PTS,
  64     VAR_STARTPTS,
  65     VAR_TB,
  66     VAR_RTCTIME,
  67     VAR_RTCSTART,
  68     VAR_VARS_NB
  69 };
  70
  71 typedef struct {
  72     AVExpr *expr;
  73     double var_values[VAR_VARS_NB];
  74 } SetPTSContext;
  75
  76 static av_cold int init(AVFilterContext *ctx, const char *args)
  77 {
  78     SetPTSContext *setpts = ctx->priv;
  79     int ret;
  80
  81     if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
  82                              var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
  83         av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
  84         return ret;
  85     }
  86
  87     setpts->var_values[VAR_E          ] = M_E;
  88     setpts->var_values[VAR_N          ] = 0.0;
  89     setpts->var_values[VAR_PHI        ] = M_PHI;
  90     setpts->var_values[VAR_PI         ] = M_PI;
  91     setpts->var_values[VAR_PREV_INPTS ] = NAN;
  92     setpts->var_values[VAR_PREV_OUTPTS] = NAN;
  93     setpts->var_values[VAR_STARTPTS   ] = NAN;
  94     return 0;
  95 }
  96
  97 static int config_input(AVFilterLink *inlink)
  98 {
  99     SetPTSContext *setpts = inlink->dst->priv;
 100
 101     setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
 102     setpts->var_values[VAR_RTCSTART] = av_gettime();
 103
 104     av_log(inlink->src, AV_LOG_VERBOSE, "TB:%f\n", setpts->var_values[VAR_TB]);
 105     return 0;
 106 }
 107
 108 #define D2TS(d)  (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
 109 #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
 110
 111 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *frame)
 112 {
 113     SetPTSContext *setpts = inlink->dst->priv;
 114     int64_t in_pts = frame->pts;
 115     double d;
 116
 117     if (isnan(setpts->var_values[VAR_STARTPTS]))
 118         setpts->var_values[VAR_STARTPTS] = TS2D(frame->pts);
 119
 120     setpts->var_values[VAR_INTERLACED] = frame->video->interlaced;
 121     setpts->var_values[VAR_PTS       ] = TS2D(frame->pts);
 122     setpts->var_values[VAR_POS       ] = frame->pos == -1 ? NAN : frame->pos;
 123     setpts->var_values[VAR_RTCTIME   ] = av_gettime();
 124
 125     d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
 126     frame->pts = D2TS(d);
 127
 128 #ifdef DEBUG
 129     av_log(inlink->dst, AV_LOG_DEBUG,
 130            "n:%"PRId64" interlaced:%d pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
 131            (int64_t)setpts->var_values[VAR_N],
 132            (int)setpts->var_values[VAR_INTERLACED],
 133            frame->pos, in_pts, in_pts * av_q2d(inlink->time_base),
 134            frame->pts, frame->pts * av_q2d(inlink->time_base));
 135 #endif
 136
 137
 138     setpts->var_values[VAR_N] += 1.0;
 139     setpts->var_values[VAR_PREV_INPTS ] = TS2D(in_pts);
 140     setpts->var_values[VAR_PREV_OUTPTS] = TS2D(frame->pts);
 141     return ff_filter_frame(inlink->dst->outputs[0], frame);
 142 }
 143
 144 static av_cold void uninit(AVFilterContext *ctx)
 145 {
 146     SetPTSContext *setpts = ctx->priv;
 147     av_expr_free(setpts->expr);
 148     setpts->expr = NULL;
 149 }
 150
 151 static const AVFilterPad avfilter_vf_setpts_inputs[] = {
 152     {
 153         .name             = "default",
 154         .type             = AVMEDIA_TYPE_VIDEO,
 155         .get_video_buffer = ff_null_get_video_buffer,
 156         .config_props     = config_input,
 157         .filter_frame     = filter_frame,
 158     },
 159     { NULL }
 160 };
 161
 162 static const AVFilterPad avfilter_vf_setpts_outputs[] = {
 163     {
 164         .name = "default",
 165         .type = AVMEDIA_TYPE_VIDEO,
 166     },
 167     { NULL }
 168 };
 169
 170 AVFilter avfilter_vf_setpts = {
 171     .name      = "setpts",
 172     .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
 173     .init      = init,
 174     .uninit    = uninit,
 175
 176     .priv_size = sizeof(SetPTSContext),
 177
 178     .inputs    = avfilter_vf_setpts_inputs,
 179     .outputs   = avfilter_vf_setpts_outputs,
 180 };