第30号一般性建议：关于妇女在预防冲突、...

Line	Branch	Exec	Source
1			/*
2			* Copyright (c) 2023 Paul B Mahol
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/channel_layout.h"
22			#include "libavutil/opt.h"
23
24			#include "audio.h"
25			#include "avfilter.h"
26			#include "filters.h"
27			#include "formats.h"
28
29			typedef struct AFDelaySrcContext {
30			const AVClass *class;
31
32			double delay;
33			int sample_rate;
34			int nb_samples;
35			int nb_taps;
36			AVChannelLayout chlayout;
37
38			int64_t pts;
39			} AFDelaySrcContext;
40
41		✗	static float sincf(float x)
42			{
43		✗	if (x == 0.f)
44		✗	return 1.f;
45		✗	return sinf(M_PI * x) / (M_PI * x);
46			}
47
48		✗	static int activate(AVFilterContext *ctx)
49			{
50		✗	AVFilterLink *outlink = ctx->outputs[0];
51		✗	AFDelaySrcContext *s = ctx->priv;
52		✗	AVFrame *frame = NULL;
53			int nb_samples;
54			float *dst;
55
56		✗	if (!ff_outlink_frame_wanted(outlink))
57		✗	return FFERROR_NOT_READY;
58
59		✗	nb_samples = FFMIN(s->nb_samples, s->nb_taps - s->pts);
60		✗	if (nb_samples <= 0) {
61		✗	ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
62		✗	return 0;
63			}
64
65		✗	if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
66		✗	return AVERROR(ENOMEM);
67
68		✗	dst = (float *)frame->extended_data[0];
69		✗	for (int n = 0; n < nb_samples; n++) {
70		✗	float x = s->pts + n;
71		✗	dst[n] = sincf(x - s->delay) * cosf(M_PI * (x - s->delay) / s->nb_taps) / sincf((x - s->delay) / s->nb_taps);
72			}
73
74		✗	for (int ch = 1; ch < frame->ch_layout.nb_channels; ch++)
75		✗	memcpy(frame->extended_data[ch], dst, sizeof(*dst) * nb_samples);
76
77		✗	frame->pts = s->pts;
78		✗	s->pts += nb_samples;
79
80		✗	return ff_filter_frame(outlink, frame);
81			}
82
83		✗	static int query_formats(const AVFilterContext *ctx,
84			AVFilterFormatsConfig **cfg_in,
85			AVFilterFormatsConfig **cfg_out)
86			{
87		✗	const AFDelaySrcContext *s = ctx->priv;
88		✗	AVChannelLayout chlayouts[] = { s->chlayout, { 0 } };
89		✗	int sample_rates[] = { s->sample_rate, -1 };
90			static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP,
91			AV_SAMPLE_FMT_NONE };
92		✗	int ret = ff_set_common_formats_from_list2(ctx, cfg_in, cfg_out, sample_fmts);
93		✗	if (ret < 0)
94		✗	return ret;
95
96		✗	ret = ff_set_common_channel_layouts_from_list2(ctx, cfg_in, cfg_out, chlayouts);
97		✗	if (ret < 0)
98		✗	return ret;
99
100		✗	return ff_set_common_samplerates_from_list2(ctx, cfg_in, cfg_out, sample_rates);
101			}
102
103		✗	static int config_output(AVFilterLink *outlink)
104			{
105		✗	AVFilterContext *ctx = outlink->src;
106		✗	AFDelaySrcContext *s = ctx->priv;
107
108		✗	outlink->sample_rate = s->sample_rate;
109		✗	s->pts = 0;
110		✗	if (s->nb_taps <= 0)
111		✗	s->nb_taps = s->delay * 8 + 1;
112
113		✗	return 0;
114			}
115
116			static const AVFilterPad afdelaysrc_outputs[] = {
117			{
118			.name = "default",
119			.type = AVMEDIA_TYPE_AUDIO,
120			.config_props = config_output,
121			},
122			};
123
124			#define AF AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
125			#define OFFSET(x) offsetof(AFDelaySrcContext, x)
126
127			static const AVOption afdelaysrc_options[] = {
128			{ "delay", "set fractional delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE,{.dbl=0}, 0, INT16_MAX, AF },
129			{ "d", "set fractional delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE,{.dbl=0}, 0, INT16_MAX, AF },
130			{ "sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF },
131			{ "r", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, INT_MAX, AF },
132			{ "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF },
133			{ "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, AF },
134			{ "taps", "set number of taps for delay filter", OFFSET(nb_taps), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
135			{ "t", "set number of taps for delay filter", OFFSET(nb_taps), AV_OPT_TYPE_INT, {.i64=0}, 0, 32768, AF },
136			{ "channel_layout", "set channel layout", OFFSET(chlayout), AV_OPT_TYPE_CHLAYOUT,{.str="stereo"},0, 0, AF },
137			{ "c", "set channel layout", OFFSET(chlayout), AV_OPT_TYPE_CHLAYOUT,{.str="stereo"},0, 0, AF },
138			{ NULL }
139			};
140
141			AVFILTER_DEFINE_CLASS(afdelaysrc);
142
143			const FFFilter ff_asrc_afdelaysrc = {
144			.p.name = "afdelaysrc",
145			.p.description = NULL_IF_CONFIG_SMALL("Generate a Fractional delay FIR coefficients."),
146			.p.priv_class = &afdelaysrc_class,
147			.priv_size = sizeof(AFDelaySrcContext),
148			.activate = activate,
149			FILTER_OUTPUTS(afdelaysrc_outputs),
150			FILTER_QUERY_FUNC2(query_formats),
151			};
152