| 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 <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 | if(amount <= 0) |
| 36 | return AVERROR(EINVAL); |
| 37 | |
| 38 | *poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); |
| 39 | if (!*poutbuf) |
| 40 | return AVERROR(ENOMEM); |
| 41 | |
| 42 | memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE); |
| 43 | for(i=0; i<buf_size; i++){ |
| 44 | (*state) += (*poutbuf)[i] + 1; |
| 45 | if(*state % amount == 0) |
| 46 | (*poutbuf)[i] = *state; |
| 47 | } |
| 48 | return 1; |
| 49 | } |
| 50 | |
| 51 | AVBitStreamFilter ff_noise_bsf={ |
| 52 | .name = "noise", |
| 53 | .priv_data_size = sizeof(int), |
| 54 | .filter = noise, |
| 55 | }; |