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
24static 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
42AVBitStreamFilter noise_bsf={
43    "noise",
44    sizeof(int),
45    noise,
46};
47