1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
/*
* Copyright (c) 2023 Paul B Mahol
*
* 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 "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "audio.h"
#include "avfilter.h"
#include "filters.h"
#include "internal.h"
typedef struct AFDelaySrcContext {
const AVClass *class;
double delay;
int sample_rate;
int nb_samples;
int nb_taps;
AVChannelLayout chlayout;
char *chlayout_str;
int64_t pts;
} AFDelaySrcContext;
static av_cold int init(AVFilterContext *ctx)
{
AFDelaySrcContext *s = ctx->priv;
int ret;
ret = ff_parse_channel_layout(&s->chlayout, NULL, s->chlayout_str, ctx);
if (ret < 0)
return ret;
return 0;
}
static float sincf(float x)
{
if (x == 0.f)
return 1.f;
return sinf(M_PI * x) / (M_PI * x);
}
static int activate(AVFilterContext *ctx)
{
AVFilterLink *outlink = ctx->outputs[0];
AFDelaySrcContext *s = ctx->priv;
AVFrame *frame = NULL;
int nb_samples;
float *dst;
if (!ff_outlink_frame_wanted(outlink))
return FFERROR_NOT_READY;
nb_samples = FFMIN(s->nb_samples, s->nb_taps - s->pts);
if (nb_samples <= 0) {
ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
return 0;
}
if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
return AVERROR(ENOMEM);
dst = (float *)frame->extended_data[0];
for (int n = 0; n < nb_samples; n++) {
float x = s->pts + n;
dst[n] = sincf(x - s->delay) * cosf(M_PI * (x - s->delay) / s->nb_taps) / sincf((x - s->delay) / s->nb_taps);
}
for (int ch = 1; ch < frame->ch_layout.nb_channels; ch++)
memcpy(frame->extended_data[ch], dst, sizeof(*dst) * nb_samples);
frame->pts = s->pts;
s->pts += nb_samples;
return ff_filter_frame(outlink, frame);
}
static int query_formats(AVFilterContext *ctx)
{
AFDelaySrcContext *s = ctx->priv;
AVChannelLayout chlayouts[] = { s->chlayout, { 0 } };
int sample_rates[] = { s->sample_rate, -1 };
static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE };
int ret = ff_set_common_formats_from_list(ctx, sample_fmts);
if (ret < 0)
return ret;
ret = ff_set_common_channel_layouts_from_list(ctx, chlayouts);
if (ret < 0)
return ret;
return ff_set_common_samplerates_from_list(ctx, sample_rates);
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
AFDelaySrcContext *s = ctx->priv;
outlink->sample_rate = s->sample_rate;
s->pts = 0;
if (s->nb_taps <= 0)
s->nb_taps = s->delay * 8 + 1;
return 0;
}
static const AVFilterPad afdelaysrc_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_output,
},
};
static av_cold void uninit(AVFilterContext *ctx)
{
AFDelaySrcContext *s = ctx->priv;
av_channel_layout_uninit(&s->chlayout);
}
#define AF AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
#define OFFSET(x) offsetof(AFDelaySrcContext, x)
static const AVOption afdelaysrc_options[] = {
{ "delay", "set fractional delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE,{.dbl=0}, 0, INT16_MAX, AF },
{ "d", "set fractional delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE,{.dbl=0}, 0, INT16_MAX, AF },
{ "sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF },
{ "r", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF },
{ "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF },
{ "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF },
{ "taps", "set number of taps for delay filter", OFFSET(nb_taps), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
{ "t", "set number of taps for delay filter", OFFSET(nb_taps), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
{ "channel_layout", "set channel layout", OFFSET(chlayout_str),AV_OPT_TYPE_STRING,{.str="stereo"},0, 0, AF },
{ "c", "set channel layout", OFFSET(chlayout_str),AV_OPT_TYPE_STRING,{.str="stereo"},0, 0, AF },
{ NULL }
};
AVFILTER_DEFINE_CLASS(afdelaysrc);
const AVFilter ff_asrc_afdelaysrc = {
.name = "afdelaysrc",
.description = NULL_IF_CONFIG_SMALL("Generate a Fractional delay FIR coefficients."),
.priv_size = sizeof(AFDelaySrcContext),
.priv_class = &afdelaysrc_class,
.init = init,
.activate = activate,
.uninit = uninit,
.inputs = NULL,
FILTER_OUTPUTS(afdelaysrc_outputs),
FILTER_QUERY_FUNC(query_formats),
};
|
