FFmpeg
af_adecorrelate.c
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1 /*
2  * Copyright (c) 2013-2020 Michael Barbour <barbour.michael.0@gmail.com>
3  * Copyright (c) 2021 Paul B Mahol
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
23 #include "libavutil/ffmath.h"
24 #include "libavutil/lfg.h"
25 #include "libavutil/random_seed.h"
26 #include "libavutil/opt.h"
27 #include "avfilter.h"
28 #include "audio.h"
29 #include "formats.h"
30 
31 #define MAX_STAGES 16
32 #define FILTER_FC 1100.0
33 #define RT60_LF 0.1
34 #define RT60_HF 0.008
35 
36 typedef struct APContext {
37  int len, p;
38  double *mx, *my;
39  double b0, b1, a0, a1;
40 } APContext;
41 
42 typedef struct ADecorrelateContext {
43  const AVClass *class;
44 
45  int stages;
46  int64_t seed;
47 
50 
52 
54  int channel,
55  AVFrame *in, AVFrame *out);
57 
58 static int ap_init(APContext *ap, int fs, double delay)
59 {
60  const int delay_samples = lrint(round(delay * fs));
61  const double gain_lf = -60.0 / (RT60_LF * fs) * delay_samples;
62  const double gain_hf = -60.0 / (RT60_HF * fs) * delay_samples;
63  const double w0 = 2.0 * M_PI * FILTER_FC / fs;
64  const double t = tan(w0 / 2.0);
65  const double g_hf = ff_exp10(gain_hf / 20.0);
66  const double gd = ff_exp10((gain_lf-gain_hf) / 20.0);
67  const double sgd = sqrt(gd);
68 
69  ap->len = delay_samples + 1;
70  ap->p = 0;
71  ap->mx = av_calloc(ap->len, sizeof(*ap->mx));
72  ap->my = av_calloc(ap->len, sizeof(*ap->my));
73  if (!ap->mx || !ap->my)
74  return AVERROR(ENOMEM);
75 
76  ap->a0 = t + sgd;
77  ap->a1 = (t - sgd) / ap->a0;
78  ap->b0 = (gd*t - sgd) / ap->a0 * g_hf;
79  ap->b1 = (gd*t + sgd) / ap->a0 * g_hf;
80  ap->a0 = 1.0;
81 
82  return 0;
83 }
84 
85 static void ap_free(APContext *ap)
86 {
87  av_freep(&ap->mx);
88  av_freep(&ap->my);
89 }
90 
91 static double ap_run(APContext *ap, double x)
92 {
93  const int i0 = ((ap->p < 1) ? ap->len : ap->p)-1, i_n1 = ap->p, i_n2 = (ap->p+1 >= ap->len) ? 0 : ap->p+1;
94  const double r = ap->b1*x + ap->b0*ap->mx[i0] + ap->a1*ap->mx[i_n2] + ap->a0*ap->mx[i_n1] -
95  ap->a1*ap->my[i0] - ap->b0*ap->my[i_n2] - ap->b1*ap->my[i_n1];
96 
97  ap->mx[ap->p] = x;
98  ap->my[ap->p] = r;
99  ap->p = (ap->p+1 >= ap->len) ? 0 : ap->p+1;
100 
101  return r;
102 }
103 
105  AVFrame *in, AVFrame *out)
106 {
107  ADecorrelateContext *s = ctx->priv;
108  const double *src = (const double *)in->extended_data[ch];
109  double *dst = (double *)out->extended_data[ch];
110  const int nb_samples = in->nb_samples;
111  const int stages = s->stages;
112  APContext *ap0 = &s->ap[ch][0];
113 
114  for (int n = 0; n < nb_samples; n++) {
115  dst[n] = ap_run(ap0, src[n]);
116  for (int i = 1; i < stages; i++) {
117  APContext *ap = &s->ap[ch][i];
118 
119  dst[n] = ap_run(ap, dst[n]);
120  }
121  }
122 }
123 
125 {
126  AVFilterContext *ctx = inlink->dst;
127  ADecorrelateContext *s = ctx->priv;
128  int ret;
129 
130  if (s->seed == -1)
131  s->seed = av_get_random_seed();
132  av_lfg_init(&s->c, s->seed);
133 
134  s->nb_channels = inlink->channels;
135  s->ap = av_calloc(inlink->channels, sizeof(*s->ap));
136  if (!s->ap)
137  return AVERROR(ENOMEM);
138 
139  for (int i = 0; i < inlink->channels; i++) {
140  for (int j = 0; j < s->stages; j++) {
141  ret = ap_init(&s->ap[i][j], inlink->sample_rate,
142  (double)av_lfg_get(&s->c) / 0xffffffff * 2.2917e-3 + 0.83333e-3);
143  if (ret < 0)
144  return ret;
145  }
146  }
147 
148  s->filter_channel = filter_channel_dbl;
149 
150  return 0;
151 }
152 
153 typedef struct ThreadData {
155 } ThreadData;
156 
157 static int filter_channels(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
158 {
159  ADecorrelateContext *s = ctx->priv;
160  ThreadData *td = arg;
161  AVFrame *out = td->out;
162  AVFrame *in = td->in;
163  const int start = (in->channels * jobnr) / nb_jobs;
164  const int end = (in->channels * (jobnr+1)) / nb_jobs;
165 
166  for (int ch = start; ch < end; ch++)
167  s->filter_channel(ctx, ch, in, out);
168 
169  return 0;
170 }
171 
173 {
174  AVFilterContext *ctx = inlink->dst;
175  AVFilterLink *outlink = ctx->outputs[0];
176  AVFrame *out;
177  ThreadData td;
178 
179  if (av_frame_is_writable(in)) {
180  out = in;
181  } else {
182  out = ff_get_audio_buffer(outlink, in->nb_samples);
183  if (!out) {
184  av_frame_free(&in);
185  return AVERROR(ENOMEM);
186  }
188  }
189 
190  td.in = in; td.out = out;
193 
194  if (out != in)
195  av_frame_free(&in);
196  return ff_filter_frame(outlink, out);
197 }
198 
200 {
201  ADecorrelateContext *s = ctx->priv;
202 
203  if (s->ap) {
204  for (int ch = 0; ch < s->nb_channels; ch++) {
205  for (int stage = 0; stage < s->stages; stage++)
206  ap_free(&s->ap[ch][stage]);
207  }
208  }
209 
210  av_freep(&s->ap);
211 }
212 
213 #define OFFSET(x) offsetof(ADecorrelateContext, x)
214 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
215 
216 static const AVOption adecorrelate_options[] = {
217  { "stages", "set filtering stages", OFFSET(stages), AV_OPT_TYPE_INT, {.i64=6}, 1, MAX_STAGES, FLAGS },
218  { "seed", "set random seed", OFFSET(seed), AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT_MAX, FLAGS },
219  { NULL }
220 };
221 
222 AVFILTER_DEFINE_CLASS(adecorrelate);
223 
224 static const AVFilterPad inputs[] = {
225  {
226  .name = "default",
227  .type = AVMEDIA_TYPE_AUDIO,
228  .filter_frame = filter_frame,
229  .config_props = config_input,
230  },
231 };
232 
233 static const AVFilterPad outputs[] = {
234  {
235  .name = "default",
236  .type = AVMEDIA_TYPE_AUDIO,
237  },
238 };
239 
241  .name = "adecorrelate",
242  .description = NULL_IF_CONFIG_SMALL("Apply decorrelation to input audio."),
243  .priv_size = sizeof(ADecorrelateContext),
244  .priv_class = &adecorrelate_class,
245  .uninit = uninit,
251 };
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:88
td
#define td
Definition: regdef.h:70
ff_exp10
static av_always_inline double ff_exp10(double x)
Compute 10^x for floating point values.
Definition: ffmath.h:42
APContext
Definition: af_adecorrelate.c:36
r
const char * r
Definition: vf_curves.c:116
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
filter_channels
static int filter_channels(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Definition: af_adecorrelate.c:157
ADecorrelateContext::filter_channel
void(* filter_channel)(AVFilterContext *ctx, int channel, AVFrame *in, AVFrame *out)
Definition: af_adecorrelate.c:53
APContext::a0
double a0
Definition: af_adecorrelate.c:39
out
FILE * out
Definition: movenc.c:54
av_lfg_init
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:32
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1018
inputs
static const AVFilterPad inputs[]
Definition: af_adecorrelate.c:224
FILTER_SINGLE_SAMPLEFMT
#define FILTER_SINGLE_SAMPLEFMT(sample_fmt_)
Definition: internal.h:184
APContext::my
double * my
Definition: af_adecorrelate.c:38
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
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
AVOption
AVOption.
Definition: opt.h:247
adecorrelate_options
static const AVOption adecorrelate_options[]
Definition: af_adecorrelate.c:216
ADecorrelateContext::c
AVLFG c
Definition: af_adecorrelate.c:51
ADecorrelateContext::ap
APContext(* ap)[MAX_STAGES]
Definition: af_adecorrelate.c:49
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:153
ThreadData::out
AVFrame * out
Definition: af_adeclick.c:473
MAX_STAGES
#define MAX_STAGES
Definition: af_adecorrelate.c:31
APContext::b1
double b1
Definition: af_adecorrelate.c:39
ap_run
static double ap_run(APContext *ap, double x)
Definition: af_adecorrelate.c:91
av_get_random_seed
uint32_t av_get_random_seed(void)
Get a seed to use in conjunction with random functions.
Definition: random_seed.c:120
formats.h
config_input
static int config_input(AVFilterLink *inlink)
Definition: af_adecorrelate.c:124
ap_init
static int ap_init(APContext *ap, int fs, double delay)
Definition: af_adecorrelate.c:58
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: af_adecorrelate.c:172
APContext::p
int p
Definition: af_adecorrelate.c:37
FLAGS
#define FLAGS
Definition: af_adecorrelate.c:214
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:50
lrint
#define lrint
Definition: tablegen.h:53
av_cold
#define av_cold
Definition: attributes.h:90
APContext::a1
double a1
Definition: af_adecorrelate.c:39
s
#define s(width, name)
Definition: cbs_vp9.c:257
OFFSET
#define OFFSET(x)
Definition: af_adecorrelate.c:213
av_lfg_get
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:53
AVFrame::channels
int channels
number of audio channels, only used for audio.
Definition: frame.h:592
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
ADecorrelateContext::stages
int stages
Definition: af_adecorrelate.c:45
lfg.h
AV_OPT_TYPE_INT64
@ AV_OPT_TYPE_INT64
Definition: opt.h:225
ctx
AVFormatContext * ctx
Definition: movenc.c:48
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: internal.h:191
arg
const char * arg
Definition: jacosubdec.c:67
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
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:537
fs
#define fs(width, name, subs,...)
Definition: cbs_vp9.c:259
src
#define src
Definition: vp8dsp.c:255
seed
static unsigned int seed
Definition: videogen.c:78
AVLFG
Context structure for the Lagged Fibonacci PRNG.
Definition: lfg.h:33
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
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(adecorrelate)
ap_free
static void ap_free(APContext *ap)
Definition: af_adecorrelate.c:85
av_frame_is_writable
int av_frame_is_writable(AVFrame *frame)
Check if the frame data is writable.
Definition: frame.c:473
filter_channel_dbl
static void filter_channel_dbl(AVFilterContext *ctx, int ch, AVFrame *in, AVFrame *out)
Definition: af_adecorrelate.c:104
ADecorrelateContext
Definition: af_adecorrelate.c:42
APContext::b0
double b0
Definition: af_adecorrelate.c:39
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_adecorrelate.c:199
APContext::mx
double * mx
Definition: af_adecorrelate.c:38
M_PI
#define M_PI
Definition: mathematics.h:52
AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
Some filters support a generic "enable" expression option that can be used to enable or disable a fil...
Definition: avfilter.h:130
AVFrame::nb_samples
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:369
APContext::len
int len
Definition: af_adecorrelate.c:37
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
round
static av_always_inline av_const double round(double x)
Definition: libm.h:444
RT60_LF
#define RT60_LF
Definition: af_adecorrelate.c:33
AVFrame::extended_data
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:350
ff_filter_get_nb_threads
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:803
ThreadData
Used for passing data between threads.
Definition: dsddec.c:67
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:56
av_calloc
void * av_calloc(size_t nmemb, size_t size)
Definition: mem.c:271
AVFilter
Filter definition.
Definition: avfilter.h:149
ff_af_adecorrelate
const AVFilter ff_af_adecorrelate
Definition: af_adecorrelate.c:240
ret
ret
Definition: filter_design.txt:187
RT60_HF
#define RT60_HF
Definition: af_adecorrelate.c:34
random_seed.h
channel_layout.h
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:224
avfilter.h
AV_SAMPLE_FMT_DBLP
@ AV_SAMPLE_FMT_DBLP
double, planar
Definition: samplefmt.h:70
ffmath.h
AVFilterContext
An instance of a filter.
Definition: avfilter.h:386
AVFILTER_FLAG_SLICE_THREADS
#define AVFILTER_FLAG_SLICE_THREADS
The filter supports multithreading by splitting frames into multiple parts and processing them concur...
Definition: avfilter.h:121
audio.h
ThreadData::in
AVFrame * in
Definition: af_adecorrelate.c:154
outputs
static const AVFilterPad outputs[]
Definition: af_adecorrelate.c:233
ADecorrelateContext::seed
int64_t seed
Definition: af_adecorrelate.c:46
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:192
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
ff_filter_execute
static av_always_inline int ff_filter_execute(AVFilterContext *ctx, avfilter_action_func *func, void *arg, int *ret, int nb_jobs)
Definition: internal.h:143
FILTER_FC
#define FILTER_FC
Definition: af_adecorrelate.c:32
channel
channel
Definition: ebur128.h:39
ADecorrelateContext::nb_channels
int nb_channels
Definition: af_adecorrelate.c:48