blob: 0aebee1ad633f7acd3e95c0c679b39a229b816f6
| 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 "bsf.h" |
| 26 | |
| 27 | #include "libavutil/log.h" |
| 28 | #include "libavutil/mem.h" |
| 29 | #include "libavutil/opt.h" |
| 30 | |
| 31 | typedef struct NoiseContext { |
| 32 | const AVClass *class; |
| 33 | int amount; |
| 34 | unsigned int state; |
| 35 | } NoiseContext; |
| 36 | |
| 37 | static int noise(AVBSFContext *ctx, AVPacket *out) |
| 38 | { |
| 39 | NoiseContext *s = ctx->priv_data; |
| 40 | AVPacket *in; |
| 41 | int amount = s->amount > 0 ? s->amount : (s->state % 10001 + 1); |
| 42 | int i, ret = 0; |
| 43 | |
| 44 | if (amount <= 0) |
| 45 | return AVERROR(EINVAL); |
| 46 | |
| 47 | ret = ff_bsf_get_packet(ctx, &in); |
| 48 | if (ret < 0) |
| 49 | return ret; |
| 50 | |
| 51 | ret = av_new_packet(out, in->size); |
| 52 | if (ret < 0) |
| 53 | goto fail; |
| 54 | |
| 55 | ret = av_packet_copy_props(out, in); |
| 56 | if (ret < 0) |
| 57 | goto fail; |
| 58 | |
| 59 | memcpy(out->data, in->data, in->size); |
| 60 | |
| 61 | for (i = 0; i < out->size; i++) { |
| 62 | s->state += out->data[i] + 1; |
| 63 | if (s->state % amount == 0) |
| 64 | out->data[i] = s->state; |
| 65 | } |
| 66 | fail: |
| 67 | if (ret < 0) |
| 68 | av_packet_unref(out); |
| 69 | av_packet_free(&in); |
| 70 | return ret; |
| 71 | } |
| 72 | |
| 73 | #define OFFSET(x) offsetof(NoiseContext, x) |
| 74 | static const AVOption options[] = { |
| 75 | { "amount", NULL, OFFSET(amount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX }, |
| 76 | { NULL }, |
| 77 | }; |
| 78 | |
| 79 | static const AVClass noise_class = { |
| 80 | .class_name = "noise", |
| 81 | .item_name = av_default_item_name, |
| 82 | .option = options, |
| 83 | .version = LIBAVUTIL_VERSION_INT, |
| 84 | }; |
| 85 | |
| 86 | const AVBitStreamFilter ff_noise_bsf = { |
| 87 | .name = "noise", |
| 88 | .priv_data_size = sizeof(NoiseContext), |
| 89 | .priv_class = &noise_class, |
| 90 | .filter = noise, |
| 91 | }; |
| 92 |