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; int amount= args ? atoi(args) : (*state % 10001+1); int i; if(amount <= 0) return AVERROR(EINVAL); *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; }