FFmpeg
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 {
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 
48  if (ret < 0)
49  return ret;
50 
51  if (s->dropamount > 0 && s->state % s->dropamount == 0) {
52  s->state++;
54  return AVERROR(EAGAIN);
55  }
56 
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)
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 };
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:599
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
AVBitStreamFilter::name
const char * name
Definition: avcodec.h:5813
AVPacket::data
uint8_t * data
Definition: avcodec.h:1477
AVOption
AVOption.
Definition: opt.h:246
NoiseContext::amount
int amount
Definition: noise_bsf.c:33
filter
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce then the filter should push the output frames on the output link immediately As an exception to the previous rule if the input frame is enough to produce several output frames then the filter needs output only at least one per link The additional frames can be left buffered in the filter
Definition: filter_design.txt:228
AVBSFContext
The bitstream filter state.
Definition: avcodec.h:5763
bsf.h
FLAGS
#define FLAGS
Definition: noise_bsf.c:74
fail
#define fail()
Definition: checkasm.h:120
NoiseContext::state
unsigned int state
Definition: noise_bsf.c:35
NoiseContext
Definition: noise_bsf.c:31
s
#define s(width, name)
Definition: cbs_vp9.c:257
ctx
AVFormatContext * ctx
Definition: movenc.c:48
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
ff_noise_bsf
const AVBitStreamFilter ff_noise_bsf
Definition: noise_bsf.c:88
NULL
#define NULL
Definition: coverity.c:32
NoiseContext::dropamount
int dropamount
Definition: noise_bsf.c:34
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
AVPacket::size
int size
Definition: avcodec.h:1478
OFFSET
#define OFFSET(x)
Definition: noise_bsf.c:73
log.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
avcodec.h
ret
ret
Definition: filter_design.txt:187
AVClass::class_name
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
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
noise
static int noise(AVBSFContext *ctx, AVPacket *pkt)
Definition: noise_bsf.c:38
AVBitStreamFilter
Definition: avcodec.h:5812
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:223
av_packet_make_writable
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:682
mem.h
options
static const AVOption options[]
Definition: noise_bsf.c:75
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1454
ff_bsf_get_packet_ref
int ff_bsf_get_packet_ref(AVBSFContext *ctx, AVPacket *pkt)
Called by bitstream filters to get packet for filtering.
Definition: bsf.c:239
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1370
noise_class
static const AVClass noise_class
Definition: noise_bsf.c:81