noise_bsf.c
Go to the documentation of this file.
1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
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 #include <stdlib.h>
22 #include <string.h>
23 
24 #include "avcodec.h"
25 #include "libavutil/mem.h"
26 
27 
28 static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
29  uint8_t **poutbuf, int *poutbuf_size,
30  const uint8_t *buf, int buf_size, int keyframe){
31  unsigned int *state= bsfc->priv_data;
32  int amount= args ? atoi(args) : (*state % 10001+1);
33  int i;
34 
35  *poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
36 
37  memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
38  for(i=0; i<buf_size; i++){
39  (*state) += (*poutbuf)[i] + 1;
40  if(*state % amount == 0)
41  (*poutbuf)[i] = *state;
42  }
43  return 1;
44 }
45 
46 AVBitStreamFilter ff_noise_bsf={
47  "noise",
48  sizeof(int),
49  noise,
50 };