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noise_bsf.c
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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;
35  unsigned int state;
36 } NoiseContext;
37 
39 {
40  NoiseContext *s = ctx->priv_data;
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_ref(ctx, pkt);
48  if (ret < 0)
49  return ret;
50 
51  if (s->dropamount > 0 && s->state % s->dropamount == 0) {
52  s->state++;
53  av_packet_unref(pkt);
54  return AVERROR(EAGAIN);
55  }
56 
57  ret = av_packet_make_writable(pkt);
58  if (ret < 0)
59  goto fail;
60 
61  for (i = 0; i < pkt->size; i++) {
62  s->state += pkt->data[i] + 1;
63  if (s->state % amount == 0)
64  pkt->data[i] = s->state;
65  }
66 fail:
67  if (ret < 0)
68  av_packet_unref(pkt);
69 
70  return ret;
71 }
72 
73 #define OFFSET(x) offsetof(NoiseContext, x)
74 #define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_BSF_PARAM)
75 static const AVOption options[] = {
76  { "amount", NULL, OFFSET(amount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
77  { "dropamount", NULL, OFFSET(dropamount), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
78  { NULL },
79 };
80 
81 static const AVClass noise_class = {
82  .class_name = "noise",
83  .item_name = av_default_item_name,
84  .option = options,
85  .version = LIBAVUTIL_VERSION_INT,
86 };
87 
89  .name = "noise",
90  .priv_data_size = sizeof(NoiseContext),
91  .priv_class = &noise_class,
92  .filter = noise,
93 };
#define NULL
Definition: coverity.c:32
static const AVClass noise_class
Definition: noise_bsf.c:81
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
Memory handling functions.
The bitstream filter state.
Definition: avcodec.h:5702
int size
Definition: avcodec.h:1445
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
static AVPacket pkt
void * priv_data
Opaque filter-specific private data.
Definition: avcodec.h:5723
#define OFFSET(x)
Definition: noise_bsf.c:73
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
static const AVOption options[]
Definition: noise_bsf.c:75
static void filter(int16_t *output, ptrdiff_t out_stride, int16_t *low, ptrdiff_t low_stride, int16_t *high, ptrdiff_t high_stride, int len, int clip)
Definition: cfhd.c:153
AVOptions.
const char * name
Definition: avcodec.h:5752
uint8_t * data
Definition: avcodec.h:1444
int av_packet_make_writable(AVPacket *pkt)
Create a writable reference for the data described by a given packet, avoiding data copy if possible...
Definition: avpacket.c:679
#define AVERROR(e)
Definition: error.h:43
#define fail()
Definition: checkasm.h:117
#define FLAGS
Definition: noise_bsf.c:74
AVFormatContext * ctx
Definition: movenc.c:48
#define s(width, name)
Definition: cbs_vp9.c:257
Libavcodec external API header.
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:598
unsigned int state
Definition: noise_bsf.c:35
Describe the class of an AVClass context structure.
Definition: log.h:67
static int noise(AVBSFContext *ctx, AVPacket *pkt)
Definition: noise_bsf.c:38
This structure stores compressed data.
Definition: avcodec.h:1421
int ff_bsf_get_packet_ref(AVBSFContext *ctx, AVPacket *pkt)
Called by bitstream filters to get packet for filtering.
Definition: bsf.c:238
int dropamount
Definition: noise_bsf.c:34
const AVBitStreamFilter ff_noise_bsf
Definition: noise_bsf.c:88