2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
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.
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.
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
27 #include "libavutil/log.h"
28 #include "libavutil/mem.h"
29 #include "libavutil/opt.h"
31 typedef struct NoiseContext {
38 static int noise(AVBSFContext *ctx, AVPacket *out)
40 NoiseContext *s = ctx->priv_data;
42 int amount = s->amount > 0 ? s->amount : (s->state % 10001 + 1);
46 return AVERROR(EINVAL);
48 ret = ff_bsf_get_packet(ctx, &in);
52 if (s->dropamount > 0 && s->state % s->dropamount == 0) {
55 return AVERROR(EAGAIN);
58 ret = av_new_packet(out, in->size);
62 ret = av_packet_copy_props(out, in);
66 memcpy(out->data, in->data, in->size);
68 for (i = 0; i < out->size; i++) {
69 s->state += out->data[i] + 1;
70 if (s->state % amount == 0)
71 out->data[i] = s->state;
80 #define OFFSET(x) offsetof(NoiseContext, x)
81 static const AVOption options[] = {
82 { "amount", NULL, OFFSET(amount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX },
83 { "dropamount", NULL, OFFSET(dropamount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX },
87 static const AVClass noise_class = {
88 .class_name = "noise",
89 .item_name = av_default_item_name,
91 .version = LIBAVUTIL_VERSION_INT,
94 const AVBitStreamFilter ff_noise_bsf = {
96 .priv_data_size = sizeof(NoiseContext),
97 .priv_class = &noise_class,