/*
 *  filter_aclip.c
 *
 *  Copyright (C) Thomas Östreich - June 2001
 *
 *  This file is part of transcode, a video stream processing tool
 *      
 *  transcode is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *   
 *  transcode 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 General Public License for more details.
 *   
 *  You should have received a copy of the GNU General Public License
 *  along with GNU Make; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 
 *
 */

#define MOD_NAME    "filter_aclip.so"
#define MOD_VERSION "v0.1.1 (2003-09-04)"
#define MOD_CAP     "generate audio clips from source"
#define MOD_AUTHOR  "Thomas Oestreich"

#include "transcode.h"
#include "filter.h"
#include "optstr.h"

#include <math.h>

static uint64_t total=0;

static int level=10, range=25, range_ctr=0, skip_mode=0;

/*-------------------------------------------------
 *
 * single function interface
 *
 *-------------------------------------------------*/

static int is_optstr(char *a)
{
    if (strchr(a, '=')) return 1;
    if (strchr(a, 'h')) return 1;
    return 0;
}

int tc_filter(aframe_list_t *ptr, char *options)
{

  int n;
  double sum;

  short *s;

  vob_t *vob=NULL;

  if(ptr->tag & TC_FILTER_GET_CONFIG) {
      optstr_filter_desc (options, MOD_NAME, MOD_CAP, MOD_VERSION, "Thomas Oestreich", "AE", "1");
      optstr_param (options, "level", "The audio must be under this level to be skipped", "%d", "10", "0", "255");
      optstr_param (options, "range", "Number of samples over level will be keyframes", "%d", "25", "0", "255");
      return 0;
  }

  //----------------------------------
  //
  // filter init
  //
  //----------------------------------

  if(ptr->tag & TC_FILTER_INIT) {
    
    if((vob = tc_get_vob())==NULL) return(-1);
    
    // filter init ok.
    
    if(verbose) printf("[%s] %s %s\n", MOD_NAME, MOD_VERSION, MOD_CAP);
    
    if(verbose) printf("[%s] options=%s\n", MOD_NAME, options);

    if(options!=NULL) {
	if (!is_optstr(options)) {
	    n=sscanf(options,"%d:%d", &level, &range);
	} else {
	    optstr_get (options, "level", "%d", &level);
	    optstr_get (options, "range", "%d", &range);
	}
    }

    range_ctr=range;
    
    return(0);
  }

  //----------------------------------
  //
  // filter close
  //
  //----------------------------------

  if(ptr->tag & TC_FILTER_CLOSE) {
    
    return(0);
  }
  
  //----------------------------------
  //
  // filter frame routine
  //
  //----------------------------------

  if(verbose & TC_STATS) printf("[%s] %s/%s %s %s\n", MOD_NAME, vob->mod_path, MOD_NAME, MOD_VERSION, MOD_CAP);
  
  // tag variable indicates, if we are called before
  // transcodes internal video/audo frame processing routines
  // or after and determines video/audio context
  
  if(ptr->tag & TC_PRE_S_PROCESS && ptr->tag & TC_AUDIO && !(ptr->attributes & TC_FRAME_IS_SKIPPED)) {
    
    total += (uint64_t) ptr->audio_size;
    
    s=(short *) ptr->audio_buf;
    
    sum=0;

    for(n=0; n<ptr->audio_size>>1; ++n) {
      sum+=(double) ((int)(*s) * (int)(*s));
      s++;
    }

    if(ptr->audio_size>0) sum = sqrt(sum)/(ptr->audio_size>>1);

    sum *= 1000;

    if(verbose & TC_DEBUG) printf("frame=%d sum=%f\n", ptr->id, sum);
    
    if(sum<level) {

      if(range_ctr == range) {
	
	ptr->attributes |= TC_FRAME_IS_SKIPPED;
	skip_mode=1;
      } else ++range_ctr;
      
    } else {
      
      if(skip_mode) ptr->attributes |= TC_FRAME_IS_KEYFRAME;
      skip_mode = 0;
      range_ctr = 0;
    }
  }
  return(0);
}
