| /* |
| * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * 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. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * 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 |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "avcodec.h" |
| #include "bsf.h" |
| |
| #include "libavutil/log.h" |
| #include "libavutil/mem.h" |
| #include "libavutil/opt.h" |
| |
| typedef struct NoiseContext { |
| const AVClass *class; |
| int amount; |
| int dropamount; |
| unsigned int state; |
| } NoiseContext; |
| |
| static int noise(AVBSFContext *ctx, AVPacket *out) |
| { |
| NoiseContext *s = ctx->priv_data; |
| AVPacket *in; |
| int amount = s->amount > 0 ? s->amount : (s->state % 10001 + 1); |
| int i, ret = 0; |
| |
| if (amount <= 0) |
| return AVERROR(EINVAL); |
| |
| ret = ff_bsf_get_packet(ctx, &in); |
| if (ret < 0) |
| return ret; |
| |
| if (s->dropamount > 0 && s->state % s->dropamount == 0) { |
| s->state++; |
| av_packet_free(&in); |
| return AVERROR(EAGAIN); |
| } |
| |
| ret = av_new_packet(out, in->size); |
| if (ret < 0) |
| goto fail; |
| |
| ret = av_packet_copy_props(out, in); |
| if (ret < 0) |
| goto fail; |
| |
| memcpy(out->data, in->data, in->size); |
| |
| for (i = 0; i < out->size; i++) { |
| s->state += out->data[i] + 1; |
| if (s->state % amount == 0) |
| out->data[i] = s->state; |
| } |
| fail: |
| if (ret < 0) |
| av_packet_unref(out); |
| av_packet_free(&in); |
| return ret; |
| } |
| |
| #define OFFSET(x) offsetof(NoiseContext, x) |
| static const AVOption options[] = { |
| { "amount", NULL, OFFSET(amount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX }, |
| { "dropamount", NULL, OFFSET(dropamount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX }, |
| { NULL }, |
| }; |
| |
| static const AVClass noise_class = { |
| .class_name = "noise", |
| .item_name = av_default_item_name, |
| .option = options, |
| .version = LIBAVUTIL_VERSION_INT, |
| }; |
| |
| const AVBitStreamFilter ff_noise_bsf = { |
| .name = "noise", |
| .priv_data_size = sizeof(NoiseContext), |
| .priv_class = &noise_class, |
| .filter = noise, |
| }; |