yading@10: /*
yading@10:  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include <stdlib.h>
yading@10: #include <string.h>
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "libavutil/mem.h"
yading@10: 
yading@10: 
yading@10: static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
yading@10:                      uint8_t **poutbuf, int *poutbuf_size,
yading@10:                      const uint8_t *buf, int buf_size, int keyframe){
yading@10:     unsigned int *state= bsfc->priv_data;
yading@10:     int amount= args ? atoi(args) : (*state % 10001+1);
yading@10:     int i;
yading@10: 
yading@10:     if(amount <= 0)
yading@10:         return AVERROR(EINVAL);
yading@10: 
yading@10:     *poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
yading@10:     if (!*poutbuf)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
yading@10:     for(i=0; i<buf_size; i++){
yading@10:         (*state) += (*poutbuf)[i] + 1;
yading@10:         if(*state % amount == 0)
yading@10:             (*poutbuf)[i] = *state;
yading@10:     }
yading@10:     return 1;
yading@10: }
yading@10: 
yading@10: AVBitStreamFilter ff_noise_bsf={
yading@10:     "noise",
yading@10:     sizeof(int),
yading@10:     noise,
yading@10: };