noise_bsf.c 1.51 KB
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/*
 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "avcodec.h"


static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
                     uint8_t **poutbuf, int *poutbuf_size,
                     const uint8_t *buf, int buf_size, int keyframe){
    unsigned int *state= bsfc->priv_data;
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    int amount= args ? atoi(args) : (*state % 10001+1);
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    int i;

    *poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

    memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
    for(i=0; i<buf_size; i++){
        (*state) += (*poutbuf)[i] + 1;
        if(*state % amount == 0)
            (*poutbuf)[i] = *state;
    }
    return 1;
}

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AVBitStreamFilter ff_noise_bsf={
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    "noise",
    sizeof(int),
    noise,
};