FFmpeg
af_tremolo.c
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1 /*
2  * Copyright (c) 2015 Kyle Swanson <k@ylo.ph>.
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 "libavutil/opt.h"
22 #include "avfilter.h"
23 #include "internal.h"
24 #include "audio.h"
25 
26 typedef struct TremoloContext {
27  const AVClass *class;
28  double freq;
29  double depth;
30  double *table;
32  int index;
34 
35 #define OFFSET(x) offsetof(TremoloContext, x)
36 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
37 
38 static const AVOption tremolo_options[] = {
39  { "f", "set frequency in hertz", OFFSET(freq), AV_OPT_TYPE_DOUBLE, {.dbl = 5.0}, 0.1, 20000.0, FLAGS },
40  { "d", "set depth as percentage", OFFSET(depth), AV_OPT_TYPE_DOUBLE, {.dbl = 0.5}, 0.0, 1.0, FLAGS },
41  { NULL }
42 };
43 
44 AVFILTER_DEFINE_CLASS(tremolo);
45 
47 {
48  AVFilterContext *ctx = inlink->dst;
49  AVFilterLink *outlink = ctx->outputs[0];
50  TremoloContext *s = ctx->priv;
51  const double *src = (const double *)in->data[0];
52  const int channels = inlink->channels;
53  const int nb_samples = in->nb_samples;
54  AVFrame *out;
55  double *dst;
56  int n, c;
57 
58  if (av_frame_is_writable(in)) {
59  out = in;
60  } else {
61  out = ff_get_audio_buffer(outlink, in->nb_samples);
62  if (!out) {
63  av_frame_free(&in);
64  return AVERROR(ENOMEM);
65  }
67  }
68  dst = (double *)out->data[0];
69 
70  for (n = 0; n < nb_samples; n++) {
71  for (c = 0; c < channels; c++)
72  dst[c] = src[c] * s->table[s->index];
73  dst += channels;
74  src += channels;
75  s->index++;
76  if (s->index >= s->table_size)
77  s->index = 0;
78  }
79 
80  if (in != out)
81  av_frame_free(&in);
82 
83  return ff_filter_frame(outlink, out);
84 }
85 
87 {
90  static const enum AVSampleFormat sample_fmts[] = {
93  };
94  int ret;
95 
97  if (!layouts)
98  return AVERROR(ENOMEM);
100  if (ret < 0)
101  return ret;
102 
104  if (!formats)
105  return AVERROR(ENOMEM);
107  if (ret < 0)
108  return ret;
109 
111  if (!formats)
112  return AVERROR(ENOMEM);
114 }
115 
117 {
118  TremoloContext *s = ctx->priv;
119  av_freep(&s->table);
120 }
121 
123 {
124  AVFilterContext *ctx = inlink->dst;
125  TremoloContext *s = ctx->priv;
126  const double offset = 1. - s->depth / 2.;
127  int i;
128 
129  s->table_size = lrint(inlink->sample_rate / s->freq + 0.5);
130  s->table = av_malloc_array(s->table_size, sizeof(*s->table));
131  if (!s->table)
132  return AVERROR(ENOMEM);
133 
134  for (i = 0; i < s->table_size; i++) {
135  double env = s->freq * i / inlink->sample_rate;
136  env = sin(2 * M_PI * fmod(env + 0.25, 1.0));
137  s->table[i] = env * (1 - fabs(offset)) + offset;
138  }
139 
140  s->index = 0;
141 
142  return 0;
143 }
144 
146  {
147  .name = "default",
148  .type = AVMEDIA_TYPE_AUDIO,
149  .config_props = config_input,
150  .filter_frame = filter_frame,
151  },
152  { NULL }
153 };
154 
156  {
157  .name = "default",
158  .type = AVMEDIA_TYPE_AUDIO,
159  },
160  { NULL }
161 };
162 
164  .name = "tremolo",
165  .description = NULL_IF_CONFIG_SMALL("Apply tremolo effect."),
166  .priv_size = sizeof(TremoloContext),
167  .priv_class = &tremolo_class,
168  .uninit = uninit,
172 };
formats
formats
Definition: signature.h:48
ff_get_audio_buffer
AVFrame * ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
Request an audio samples buffer with a specific set of permissions.
Definition: audio.c:86
AVFilterChannelLayouts
A list of supported channel layouts.
Definition: formats.h:86
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
ff_make_format_list
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:286
FLAGS
#define FLAGS
Definition: af_tremolo.c:36
out
FILE * out
Definition: movenc.c:54
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:978
sample_fmts
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:953
layouts
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:434
ff_af_tremolo
const AVFilter ff_af_tremolo
Definition: af_tremolo.c:163
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
TremoloContext
Definition: af_tremolo.c:26
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:111
ff_all_channel_counts
AVFilterChannelLayouts * ff_all_channel_counts(void)
Construct an AVFilterChannelLayouts coding for any channel layout, with known or unknown disposition.
Definition: formats.c:429
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
OFFSET
#define OFFSET(x)
Definition: af_tremolo.c:35
AVOption
AVOption.
Definition: opt.h:248
TremoloContext::freq
double freq
Definition: af_tremolo.c:28
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:149
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:317
AVFilterFormats
A list of supported formats for one end of a filter link.
Definition: formats.h:65
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: af_tremolo.c:46
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:54
lrint
#define lrint
Definition: tablegen.h:53
av_cold
#define av_cold
Definition: attributes.h:90
inputs
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
Definition: filter_design.txt:243
ff_set_common_formats
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:580
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_OPT_TYPE_DOUBLE
@ AV_OPT_TYPE_DOUBLE
Definition: opt.h:227
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
outputs
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
ctx
AVFormatContext * ctx
Definition: movenc.c:48
channels
channels
Definition: aptx.h:33
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: af_tremolo.c:86
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(tremolo)
if
if(ret)
Definition: filter_design.txt:179
avfilter_af_tremolo_inputs
static const AVFilterPad avfilter_af_tremolo_inputs[]
Definition: af_tremolo.c:145
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
fabs
static __device__ float fabs(float a)
Definition: cuda_runtime.h:182
NULL
#define NULL
Definition: coverity.c:32
av_frame_copy_props
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:536
src
#define src
Definition: vp8dsp.c:255
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
for
for(j=16;j >0;--j)
Definition: h264pred_template.c:469
TremoloContext::table_size
int table_size
Definition: af_tremolo.c:31
TremoloContext::table
double * table
Definition: af_tremolo.c:30
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
av_frame_is_writable
int av_frame_is_writable(AVFrame *frame)
Check if the frame data is writable.
Definition: frame.c:472
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
config_input
static int config_input(AVFilterLink *inlink)
Definition: af_tremolo.c:122
M_PI
#define M_PI
Definition: mathematics.h:52
internal.h
AVFrame::nb_samples
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:369
i
int i
Definition: input.c:407
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_tremolo.c:116
av_malloc_array
#define av_malloc_array(a, b)
Definition: tableprint_vlc.h:32
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
avfilter_af_tremolo_outputs
static const AVFilterPad avfilter_af_tremolo_outputs[]
Definition: af_tremolo.c:155
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:60
AVFilter
Filter definition.
Definition: avfilter.h:145
ret
ret
Definition: filter_design.txt:187
tremolo_options
static const AVOption tremolo_options[]
Definition: af_tremolo.c:38
ff_all_samplerates
AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:414
avfilter.h
TremoloContext::depth
double depth
Definition: af_tremolo.c:29
AVFilterContext
An instance of a filter.
Definition: avfilter.h:333
audio.h
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
ff_set_common_samplerates
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:568
AV_SAMPLE_FMT_DBL
@ AV_SAMPLE_FMT_DBL
double
Definition: samplefmt.h:64
TremoloContext::index
int index
Definition: af_tremolo.c:32
ff_set_common_channel_layouts
int ff_set_common_channel_layouts(AVFilterContext *ctx, AVFilterChannelLayouts *channel_layouts)
A helper for query_formats() which sets all links to the same list of channel layouts/sample rates.
Definition: formats.c:561