1 /*
2 * Copyright (c) 2012 Michael Niedermayer
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 /**
22 * @file
23 * audio pad filter.
24 *
25 * Based on af_aresample.c
26 */
27
28 #include "libavutil/avstring.h"
29 #include "libavutil/channel_layout.h"
30 #include "libavutil/opt.h"
31 #include "libavutil/samplefmt.h"
32 #include "libavutil/avassert.h"
33 #include "avfilter.h"
34 #include "audio.h"
35 #include "internal.h"
36
37 typedef struct APadContext {
38 const AVClass *class;
39 int64_t next_pts;
40
41 int packet_size;
42 int64_t pad_len, pad_len_left;
43 int64_t whole_len, whole_len_left;
44 int64_t pad_dur;
45 int64_t whole_dur;
46 } APadContext;
47
48 #define OFFSET(x) offsetof(APadContext, x)
49 #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
50
51 static const AVOption apad_options[] = {
52 { "packet_size", "set silence packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, { .i64 = 4096 }, 0, INT_MAX, A },
53 { "pad_len", "set number of samples of silence to add", OFFSET(pad_len), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, A },
54 { "whole_len", "set minimum target number of samples in the audio stream", OFFSET(whole_len), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, A },
55 { "pad_dur", "set duration of silence to add", OFFSET(pad_dur), AV_OPT_TYPE_DURATION, { .i64 = 0 }, 0, INT64_MAX, A },
56 { "whole_dur", "set minimum target duration in the audio stream", OFFSET(whole_dur), AV_OPT_TYPE_DURATION, { .i64 = 0 }, 0, INT64_MAX, A },
57 { NULL }
58 };
59
60 AVFILTER_DEFINE_CLASS(apad);
61
init(AVFilterContext * ctx)62 static av_cold int init(AVFilterContext *ctx)
63 {
64 APadContext *s = ctx->priv;
65
66 s->next_pts = AV_NOPTS_VALUE;
67 if (s->whole_len >= 0 && s->pad_len >= 0) {
68 av_log(ctx, AV_LOG_ERROR, "Both whole and pad length are set, this is not possible\n");
69 return AVERROR(EINVAL);
70 }
71
72 return 0;
73 }
74
filter_frame(AVFilterLink * inlink,AVFrame * frame)75 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
76 {
77 AVFilterContext *ctx = inlink->dst;
78 APadContext *s = ctx->priv;
79
80 if (s->whole_len >= 0) {
81 s->whole_len_left = FFMAX(s->whole_len_left - frame->nb_samples, 0);
82 av_log(ctx, AV_LOG_DEBUG,
83 "n_out:%d whole_len_left:%"PRId64"\n", frame->nb_samples, s->whole_len_left);
84 }
85
86 s->next_pts = frame->pts + av_rescale_q(frame->nb_samples, (AVRational){1, inlink->sample_rate}, inlink->time_base);
87 return ff_filter_frame(ctx->outputs[0], frame);
88 }
89
request_frame(AVFilterLink * outlink)90 static int request_frame(AVFilterLink *outlink)
91 {
92 AVFilterContext *ctx = outlink->src;
93 APadContext *s = ctx->priv;
94 int ret;
95
96 ret = ff_request_frame(ctx->inputs[0]);
97
98 if (ret == AVERROR_EOF && !ctx->is_disabled) {
99 int n_out = s->packet_size;
100 AVFrame *outsamplesref;
101
102 if (s->whole_len >= 0 && s->pad_len < 0) {
103 s->pad_len = s->pad_len_left = s->whole_len_left;
104 }
105 if (s->pad_len >=0 || s->whole_len >= 0) {
106 n_out = FFMIN(n_out, s->pad_len_left);
107 s->pad_len_left -= n_out;
108 av_log(ctx, AV_LOG_DEBUG,
109 "padding n_out:%d pad_len_left:%"PRId64"\n", n_out, s->pad_len_left);
110 }
111
112 if (!n_out)
113 return AVERROR_EOF;
114
115 outsamplesref = ff_get_audio_buffer(outlink, n_out);
116 if (!outsamplesref)
117 return AVERROR(ENOMEM);
118
119 av_assert0(outsamplesref->sample_rate == outlink->sample_rate);
120 av_assert0(outsamplesref->nb_samples == n_out);
121
122 av_samples_set_silence(outsamplesref->extended_data, 0,
123 n_out,
124 outsamplesref->channels,
125 outsamplesref->format);
126
127 outsamplesref->pts = s->next_pts;
128 if (s->next_pts != AV_NOPTS_VALUE)
129 s->next_pts += av_rescale_q(n_out, (AVRational){1, outlink->sample_rate}, outlink->time_base);
130
131 return ff_filter_frame(outlink, outsamplesref);
132 }
133 return ret;
134 }
135
config_output(AVFilterLink * outlink)136 static int config_output(AVFilterLink *outlink)
137 {
138 AVFilterContext *ctx = outlink->src;
139 APadContext *s = ctx->priv;
140
141 if (s->pad_dur)
142 s->pad_len = av_rescale(s->pad_dur, outlink->sample_rate, AV_TIME_BASE);
143 if (s->whole_dur)
144 s->whole_len = av_rescale(s->whole_dur, outlink->sample_rate, AV_TIME_BASE);
145
146 s->pad_len_left = s->pad_len;
147 s->whole_len_left = s->whole_len;
148
149 return 0;
150 }
151
152 static const AVFilterPad apad_inputs[] = {
153 {
154 .name = "default",
155 .type = AVMEDIA_TYPE_AUDIO,
156 .filter_frame = filter_frame,
157 },
158 { NULL }
159 };
160
161 static const AVFilterPad apad_outputs[] = {
162 {
163 .name = "default",
164 .request_frame = request_frame,
165 .config_props = config_output,
166 .type = AVMEDIA_TYPE_AUDIO,
167 },
168 { NULL }
169 };
170
171 AVFilter ff_af_apad = {
172 .name = "apad",
173 .description = NULL_IF_CONFIG_SMALL("Pad audio with silence."),
174 .init = init,
175 .priv_size = sizeof(APadContext),
176 .inputs = apad_inputs,
177 .outputs = apad_outputs,
178 .priv_class = &apad_class,
179 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
180 };
181