/*

  * Copyright (c) 2010 Stefano Sabatini

  *
  * 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
  * Set timebase for the output link.
  */
 

 #include <inttypes.h>
 #include <stdio.h>
 

 #include "libavutil/avstring.h"
 #include "libavutil/eval.h"

 #include "libavutil/internal.h"

 #include "libavutil/mathematics.h"

 #include "libavutil/opt.h"

 #include "libavutil/rational.h"

 #include "audio.h"

 #include "avfilter.h"
 #include "internal.h"

 #include "video.h"

 static const char *const var_names[] = {

     "AVTB",   /* default timebase 1/AV_TIME_BASE */
     "intb",   /* input timebase */

     "sr",     /* sample rate */

     NULL
 };
 
 enum var_name {
     VAR_AVTB,
     VAR_INTB,

     VAR_SR,

     VAR_VARS_NB
 };
 

 typedef struct SetTBContext {

     const AVClass *class;
     char *tb_expr;

     double var_values[VAR_VARS_NB];
 } SetTBContext;
 

 #define OFFSET(x) offsetof(SetTBContext, x)
 #define DEFINE_OPTIONS(filt_name, filt_type)                                               \
 static const AVOption filt_name##_options[] = {                                            \

     { "expr", "set expression determining the output timebase", OFFSET(tb_expr), AV_OPT_TYPE_STRING, {.str="intb"}, \
            .flags=AV_OPT_FLAG_##filt_type##_PARAM|AV_OPT_FLAG_FILTERING_PARAM },           \
     { "tb",   "set expression determining the output timebase", OFFSET(tb_expr), AV_OPT_TYPE_STRING, {.str="intb"}, \

            .flags=AV_OPT_FLAG_##filt_type##_PARAM|AV_OPT_FLAG_FILTERING_PARAM },           \
     { NULL }                                                                               \
 }
 

 static int config_output_props(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     SetTBContext *settb = ctx->priv;
     AVFilterLink *inlink = ctx->inputs[0];
     AVRational time_base;
     int ret;
     double res;
 
     settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
     settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);

     settb->var_values[VAR_SR]   = inlink->sample_rate;

 
     outlink->w = inlink->w;
     outlink->h = inlink->h;
 

     if ((ret = av_expr_parse_and_eval(&res, settb->tb_expr, var_names, settb->var_values,

                                       NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
         av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
         return ret;
     }
     time_base = av_d2q(res, INT_MAX);
     if (time_base.num <= 0 || time_base.den <= 0) {
         av_log(ctx, AV_LOG_ERROR,
                "Invalid non-positive values for the timebase num:%d or den:%d.\n",
                time_base.num, time_base.den);
         return AVERROR(EINVAL);
     }
 
     outlink->time_base = time_base;

     av_log(outlink->src, AV_LOG_VERBOSE, "tb:%d/%d -> tb:%d/%d\n",

            inlink ->time_base.num, inlink ->time_base.den,
            outlink->time_base.num, outlink->time_base.den);
 
     return 0;
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)

 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
 
     if (av_cmp_q(inlink->time_base, outlink->time_base)) {

         int64_t orig_pts = frame->pts;
         frame->pts = av_rescale_q(frame->pts, inlink->time_base, outlink->time_base);

         av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",

                inlink ->time_base.num, inlink ->time_base.den, orig_pts,

                outlink->time_base.num, outlink->time_base.den, frame->pts);

     }
 

     return ff_filter_frame(outlink, frame);

 }
 
 #if CONFIG_SETTB_FILTER

 
 DEFINE_OPTIONS(settb, VIDEO);
 AVFILTER_DEFINE_CLASS(settb);
 

 static const AVFilterPad avfilter_vf_settb_inputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,

     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_vf_settb_outputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_output_props,
     },
     { NULL }
 };
 

 AVFilter ff_vf_settb = {

     .name        = "settb",

     .description = NULL_IF_CONFIG_SMALL("Set timebase for the video output link."),

     .priv_size   = sizeof(SetTBContext),
     .priv_class  = &settb_class,
     .inputs      = avfilter_vf_settb_inputs,
     .outputs     = avfilter_vf_settb_outputs,

 };

 #endif /* CONFIG_SETTB_FILTER */

 
 #if CONFIG_ASETTB_FILTER

 
 DEFINE_OPTIONS(asettb, AUDIO);
 AVFILTER_DEFINE_CLASS(asettb);
 

 static const AVFilterPad avfilter_af_asettb_inputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,

     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_af_asettb_outputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .config_props = config_output_props,
     },
     { NULL }
 };
 

 AVFilter ff_af_asettb = {

     .name        = "asettb",

     .description = NULL_IF_CONFIG_SMALL("Set timebase for the audio output link."),

     .priv_size   = sizeof(SetTBContext),
     .inputs      = avfilter_af_asettb_inputs,
     .outputs     = avfilter_af_asettb_outputs,
     .priv_class  = &asettb_class,

 };

 #endif /* CONFIG_ASETTB_FILTER */