libavcodec/noise_bsf.c

   1 /*
   2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "avcodec.h"
  22
  23
  24 static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
  25                      uint8_t **poutbuf, int *poutbuf_size,
  26                      const uint8_t *buf, int buf_size, int keyframe){
  27     unsigned int *state= bsfc->priv_data;
  28     int amount= args ? atoi(args) : (*state % 10001+1);
  29     int i;
  30
  31     *poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
  32
  33     memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
  34     for(i=0; i<buf_size; i++){
  35         (*state) += (*poutbuf)[i] + 1;
  36         if(*state % amount == 0)
  37             (*poutbuf)[i] = *state;
  38     }
  39     return 1;
  40 }
  41
  42 AVBitStreamFilter noise_bsf={
  43     "noise",
  44     sizeof(int),
  45     noise,
  46 };