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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 "internal.h" | |
36 | ||
37 | typedef struct { | |
38 | const AVClass *class; | |
39 | char *channel_layout_str; | |
40 | uint64_t channel_layout; | |
41 | char *sample_rate_str; | |
42 | int sample_rate; | |
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(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, FLAGS }, | |
52 | { "cl", "set channel_layout", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, {.str = "stereo"}, 0, 0, FLAGS }, | |
53 | { "sample_rate", "set sample rate", OFFSET(sample_rate_str) , AV_OPT_TYPE_STRING, {.str = "44100"}, 0, 0, FLAGS }, | |
54 | { "r", "set sample rate", OFFSET(sample_rate_str) , AV_OPT_TYPE_STRING, {.str = "44100"}, 0, 0, FLAGS }, | |
55 | { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS }, | |
56 | { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS }, | |
57 | { NULL } | |
58 | }; | |
59 | ||
60 | AVFILTER_DEFINE_CLASS(anullsrc); | |
61 | ||
62 | static av_cold int init(AVFilterContext *ctx) | |
63 | { | |
64 | ANullContext *null = ctx->priv; | |
65 | int ret; | |
66 | ||
67 | if ((ret = ff_parse_sample_rate(&null->sample_rate, | |
68 | null->sample_rate_str, ctx)) < 0) | |
69 | return ret; | |
70 | ||
71 | if ((ret = ff_parse_channel_layout(&null->channel_layout, NULL, | |
72 | null->channel_layout_str, ctx)) < 0) | |
73 | return ret; | |
74 | ||
75 | return 0; | |
76 | } | |
77 | ||
78 | static int query_formats(AVFilterContext *ctx) | |
79 | { | |
80 | ANullContext *null = ctx->priv; | |
81 | int64_t chlayouts[] = { null->channel_layout, -1 }; | |
82 | int sample_rates[] = { null->sample_rate, -1 }; | |
83 | ||
84 | ff_set_common_formats (ctx, ff_all_formats(AVMEDIA_TYPE_AUDIO)); | |
85 | ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts)); | |
86 | ff_set_common_samplerates (ctx, ff_make_format_list(sample_rates)); | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | static int config_props(AVFilterLink *outlink) | |
92 | { | |
93 | ANullContext *null = outlink->src->priv; | |
94 | char buf[128]; | |
95 | ||
96 | av_get_channel_layout_string(buf, sizeof(buf), 0, null->channel_layout); | |
97 | av_log(outlink->src, AV_LOG_VERBOSE, | |
98 | "sample_rate:%d channel_layout:'%s' nb_samples:%d\n", | |
99 | null->sample_rate, buf, null->nb_samples); | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | static int request_frame(AVFilterLink *outlink) | |
105 | { | |
106 | int ret; | |
107 | ANullContext *null = outlink->src->priv; | |
108 | AVFrame *samplesref; | |
109 | ||
110 | samplesref = ff_get_audio_buffer(outlink, null->nb_samples); | |
111 | if (!samplesref) | |
112 | return AVERROR(ENOMEM); | |
113 | ||
114 | samplesref->pts = null->pts; | |
115 | samplesref->channel_layout = null->channel_layout; | |
116 | samplesref->sample_rate = outlink->sample_rate; | |
117 | ||
118 | ret = ff_filter_frame(outlink, av_frame_clone(samplesref)); | |
119 | av_frame_free(&samplesref); | |
120 | if (ret < 0) | |
121 | return ret; | |
122 | ||
123 | null->pts += null->nb_samples; | |
124 | return ret; | |
125 | } | |
126 | ||
127 | static const AVFilterPad avfilter_asrc_anullsrc_outputs[] = { | |
128 | { | |
129 | .name = "default", | |
130 | .type = AVMEDIA_TYPE_AUDIO, | |
131 | .config_props = config_props, | |
132 | .request_frame = request_frame, | |
133 | }, | |
134 | { NULL } | |
135 | }; | |
136 | ||
137 | AVFilter ff_asrc_anullsrc = { | |
138 | .name = "anullsrc", | |
139 | .description = NULL_IF_CONFIG_SMALL("Null audio source, return empty audio frames."), | |
140 | .init = init, | |
141 | .query_formats = query_formats, | |
142 | .priv_size = sizeof(ANullContext), | |
143 | .inputs = NULL, | |
144 | .outputs = avfilter_asrc_anullsrc_outputs, | |
145 | .priv_class = &anullsrc_class, | |
146 | }; |