FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavfilter/asrc_anullsrc.c
Date: 2026-04-24 19:58:39
Exec Total Coverage
Lines: 21 27 77.8%
Functions: 3 3 100.0%
Branches: 6 14 42.9%
Line Branch Exec Source
1 /*
2 * Copyright 2010 S.N. Hemanth Meenakshisundaram <smeenaks ucsd edu>
3 * Copyright 2010 Stefano Sabatini <stefano.sabatini-lala poste it>
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
22 /**
23 * @file
24 * null audio source
25 */
26
27 #include <inttypes.h>
28 #include <stdio.h>
29
30 #include "libavutil/channel_layout.h"
31 #include "libavutil/internal.h"
32 #include "libavutil/opt.h"
33 #include "audio.h"
34 #include "avfilter.h"
35 #include "filters.h"
36 #include "formats.h"
37
38 typedef struct ANullContext {
39 const AVClass *class;
40 AVChannelLayout ch_layout;
41 int sample_rate;
42 int64_t duration;
43 int nb_samples; ///< number of samples per requested frame
44 int64_t pts;
45 } ANullContext;
46
47 #define OFFSET(x) offsetof(ANullContext, x)
48 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
49
50 static const AVOption anullsrc_options[]= {
51 { "channel_layout", "set channel_layout", OFFSET(ch_layout), AV_OPT_TYPE_CHLAYOUT, {.str = "stereo"}, 0, 0, FLAGS },
52 { "cl", "set channel_layout", OFFSET(ch_layout), AV_OPT_TYPE_CHLAYOUT, {.str = "stereo"}, 0, 0, FLAGS },
53 { "sample_rate", "set sample rate", OFFSET(sample_rate) , AV_OPT_TYPE_INT, {.i64 = 44100}, 1, INT_MAX, FLAGS },
54 { "r", "set sample rate", OFFSET(sample_rate) , AV_OPT_TYPE_INT, {.i64 = 44100}, 1, INT_MAX, FLAGS },
55 { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, UINT16_MAX, FLAGS },
56 { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, UINT16_MAX, FLAGS },
57 { "duration", "set the audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
58 { "d", "set the audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
59 { NULL }
60 };
61
62 AVFILTER_DEFINE_CLASS(anullsrc);
63
64 1 static int query_formats(const AVFilterContext *ctx,
65 AVFilterFormatsConfig **cfg_in,
66 AVFilterFormatsConfig **cfg_out)
67 {
68 1 const ANullContext *null = ctx->priv;
69 1 const AVChannelLayout chlayouts[] = { null->ch_layout, { 0 } };
70 1 int sample_rates[] = { null->sample_rate, -1 };
71 int ret;
72
73 1 ret = ff_set_common_samplerates_from_list2(ctx, cfg_in, cfg_out, sample_rates);
74
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 1 if (ret < 0)
75 ✗ return ret;
76
77 1 return ff_set_common_channel_layouts_from_list2(ctx, cfg_in, cfg_out, chlayouts);
78 }
79
80 1 static av_cold int config_props(AVFilterLink *outlink)
81 {
82 1 ANullContext *null = outlink->src->priv;
83
84
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 1 if (null->duration >= 0)
85 ✗ null->duration = av_rescale(null->duration, null->sample_rate, AV_TIME_BASE);
86
87 1 return 0;
88 }
89
90 88 static int activate(AVFilterContext *ctx)
91 {
92 88 ANullContext *null = ctx->priv;
93 88 AVFilterLink *outlink = ctx->outputs[0];
94
95
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 88 if (null->duration >= 0 && null->pts >= null->duration) {
96 ✗ ff_outlink_set_status(outlink, AVERROR_EOF, null->pts);
97 ✗ return 0;
98 }
99
100
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 88 if (ff_outlink_frame_wanted(outlink)) {
101
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 88 AVFrame *samplesref = ff_get_audio_buffer(outlink, null->duration >= 0 ? FFMIN(null->nb_samples, null->duration - null->pts) : null->nb_samples);
102
103
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 88 if (!samplesref)
104 ✗ return AVERROR(ENOMEM);
105
106 88 samplesref->pts = null->pts;
107 88 null->pts += samplesref->nb_samples;
108
109 88 return ff_filter_frame(outlink, samplesref);
110 }
111
112 ✗ return FFERROR_NOT_READY;
113 }
114
115 static const AVFilterPad avfilter_asrc_anullsrc_outputs[] = {
116 {
117 .name = "default",
118 .type = AVMEDIA_TYPE_AUDIO,
119 .config_props = config_props,
120 },
121 };
122
123 const FFFilter ff_asrc_anullsrc = {
124 .p.name = "anullsrc",
125 .p.description = NULL_IF_CONFIG_SMALL("Null audio source, return empty audio frames."),
126 .p.priv_class = &anullsrc_class,
127 .priv_size = sizeof(ANullContext),
128 FILTER_OUTPUTS(avfilter_asrc_anullsrc_outputs),
129 FILTER_QUERY_FUNC2(query_formats),
130 .activate = activate,
131 };
132