libavfilter/vf_settb.c

   1 /*
   2  * Copyright (c) 2010 Stefano Sabatini
   3  *
   4  * This file is part of Libav.
   5  *
   6  * Libav is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * Libav is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with Libav; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * Set timebase for the output link.
  24  */
  25
  26 #include <inttypes.h>
  27 #include <stdio.h>
  28
  29 #include "libavutil/avstring.h"
  30 #include "libavutil/eval.h"
  31 #include "libavutil/internal.h"
  32 #include "libavutil/mathematics.h"
  33 #include "libavutil/rational.h"
  34 #include "avfilter.h"
  35 #include "internal.h"
  36 #include "video.h"
  37
  38 static const char *const var_names[] = {
  39     "E",
  40     "PHI",
  41     "PI",
  42     "AVTB",   /* default timebase 1/AV_TIME_BASE */
  43     "intb",   /* input timebase */
  44     NULL
  45 };
  46
  47 enum var_name {
  48     VAR_E,
  49     VAR_PHI,
  50     VAR_PI,
  51     VAR_AVTB,
  52     VAR_INTB,
  53     VAR_VARS_NB
  54 };
  55
  56 typedef struct {
  57     char tb_expr[256];
  58     double var_values[VAR_VARS_NB];
  59 } SetTBContext;
  60
  61 static av_cold int init(AVFilterContext *ctx, const char *args)
  62 {
  63     SetTBContext *settb = ctx->priv;
  64     av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
  65
  66     if (args)
  67         sscanf(args, "%255[^:]", settb->tb_expr);
  68
  69     return 0;
  70 }
  71
  72 static int config_output_props(AVFilterLink *outlink)
  73 {
  74     AVFilterContext *ctx = outlink->src;
  75     SetTBContext *settb = ctx->priv;
  76     AVFilterLink *inlink = ctx->inputs[0];
  77     AVRational time_base;
  78     int ret;
  79     double res;
  80
  81     settb->var_values[VAR_E]    = M_E;
  82     settb->var_values[VAR_PHI]  = M_PHI;
  83     settb->var_values[VAR_PI]   = M_PI;
  84     settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
  85     settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
  86
  87     outlink->w = inlink->w;
  88     outlink->h = inlink->h;
  89
  90     if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,
  91                                       NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
  92         av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
  93         return ret;
  94     }
  95     time_base = av_d2q(res, INT_MAX);
  96     if (time_base.num <= 0 || time_base.den <= 0) {
  97         av_log(ctx, AV_LOG_ERROR,
  98                "Invalid non-positive values for the timebase num:%d or den:%d.\n",
  99                time_base.num, time_base.den);
 100         return AVERROR(EINVAL);
 101     }
 102
 103     outlink->time_base = time_base;
 104     av_log(outlink->src, AV_LOG_VERBOSE, "tb:%d/%d -> tb:%d/%d\n",
 105            inlink ->time_base.num, inlink ->time_base.den,
 106            outlink->time_base.num, outlink->time_base.den);
 107
 108     return 0;
 109 }
 110
 111 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 112 {
 113     AVFilterContext *ctx = inlink->dst;
 114     AVFilterLink *outlink = ctx->outputs[0];
 115
 116     if (av_cmp_q(inlink->time_base, outlink->time_base)) {
 117         int64_t orig_pts = frame->pts;
 118         frame->pts = av_rescale_q(frame->pts, inlink->time_base, outlink->time_base);
 119         av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
 120                inlink ->time_base.num, inlink ->time_base.den, orig_pts,
 121                outlink->time_base.num, outlink->time_base.den, frame->pts);
 122     }
 123
 124     return ff_filter_frame(outlink, frame);
 125 }
 126
 127 static const AVFilterPad avfilter_vf_settb_inputs[] = {
 128     {
 129         .name             = "default",
 130         .type             = AVMEDIA_TYPE_VIDEO,
 131         .get_video_buffer = ff_null_get_video_buffer,
 132         .filter_frame     = filter_frame,
 133     },
 134     { NULL }
 135 };
 136
 137 static const AVFilterPad avfilter_vf_settb_outputs[] = {
 138     {
 139         .name         = "default",
 140         .type         = AVMEDIA_TYPE_VIDEO,
 141         .config_props = config_output_props,
 142     },
 143     { NULL }
 144 };
 145
 146 AVFilter avfilter_vf_settb = {
 147     .name      = "settb",
 148     .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
 149     .init      = init,
 150
 151     .priv_size = sizeof(SetTBContext),
 152
 153     .inputs    = avfilter_vf_settb_inputs,
 154
 155     .outputs   = avfilter_vf_settb_outputs,
 156 };