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path: root/libavfilter/af_asetnsamples.c (plain)
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1/*
2 * Copyright (c) 2012 Andrey Utkin
3 * Copyright (c) 2012 Stefano Sabatini
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 * Filter that changes number of samples on single output operation
25 */
26
27#include "libavutil/audio_fifo.h"
28#include "libavutil/avassert.h"
29#include "libavutil/channel_layout.h"
30#include "libavutil/opt.h"
31#include "avfilter.h"
32#include "audio.h"
33#include "internal.h"
34#include "formats.h"
35
36typedef struct {
37 const AVClass *class;
38 int nb_out_samples; ///< how many samples to output
39 AVAudioFifo *fifo; ///< samples are queued here
40 int64_t next_out_pts;
41 int pad;
42} ASNSContext;
43
44#define OFFSET(x) offsetof(ASNSContext, x)
45#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
46
47static const AVOption asetnsamples_options[] = {
48 { "nb_out_samples", "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },
49 { "n", "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },
50 { "pad", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },
51 { "p", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },
52 { NULL }
53};
54
55AVFILTER_DEFINE_CLASS(asetnsamples);
56
57static av_cold int init(AVFilterContext *ctx)
58{
59 ASNSContext *asns = ctx->priv;
60
61 asns->next_out_pts = AV_NOPTS_VALUE;
62 av_log(ctx, AV_LOG_VERBOSE, "nb_out_samples:%d pad:%d\n", asns->nb_out_samples, asns->pad);
63
64 return 0;
65}
66
67static av_cold void uninit(AVFilterContext *ctx)
68{
69 ASNSContext *asns = ctx->priv;
70 av_audio_fifo_free(asns->fifo);
71}
72
73static int config_props_output(AVFilterLink *outlink)
74{
75 ASNSContext *asns = outlink->src->priv;
76
77 asns->fifo = av_audio_fifo_alloc(outlink->format, outlink->channels, asns->nb_out_samples);
78 if (!asns->fifo)
79 return AVERROR(ENOMEM);
80
81 return 0;
82}
83
84static int push_samples(AVFilterLink *outlink)
85{
86 ASNSContext *asns = outlink->src->priv;
87 AVFrame *outsamples = NULL;
88 int ret, nb_out_samples, nb_pad_samples;
89
90 if (asns->pad) {
91 nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0;
92 nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo));
93 } else {
94 nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo));
95 nb_pad_samples = 0;
96 }
97
98 if (!nb_out_samples)
99 return 0;
100
101 outsamples = ff_get_audio_buffer(outlink, nb_out_samples);
102 if (!outsamples)
103 return AVERROR(ENOMEM);
104
105 av_audio_fifo_read(asns->fifo,
106 (void **)outsamples->extended_data, nb_out_samples);
107
108 if (nb_pad_samples)
109 av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples,
110 nb_pad_samples, outlink->channels,
111 outlink->format);
112 outsamples->nb_samples = nb_out_samples;
113 outsamples->channel_layout = outlink->channel_layout;
114 outsamples->sample_rate = outlink->sample_rate;
115 outsamples->pts = asns->next_out_pts;
116
117 if (asns->next_out_pts != AV_NOPTS_VALUE)
118 asns->next_out_pts += av_rescale_q(nb_out_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base);
119
120 ret = ff_filter_frame(outlink, outsamples);
121 if (ret < 0)
122 return ret;
123 return nb_out_samples;
124}
125
126static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
127{
128 AVFilterContext *ctx = inlink->dst;
129 ASNSContext *asns = ctx->priv;
130 AVFilterLink *outlink = ctx->outputs[0];
131 int ret;
132 int nb_samples = insamples->nb_samples;
133
134 if (av_audio_fifo_space(asns->fifo) < nb_samples) {
135 av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples);
136 ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples);
137 if (ret < 0) {
138 av_log(ctx, AV_LOG_ERROR,
139 "Stretching audio fifo failed, discarded %d samples\n", nb_samples);
140 return -1;
141 }
142 }
143 av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
144 if (asns->next_out_pts == AV_NOPTS_VALUE)
145 asns->next_out_pts = insamples->pts;
146 av_frame_free(&insamples);
147
148 while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)
149 push_samples(outlink);
150 return 0;
151}
152
153static int request_frame(AVFilterLink *outlink)
154{
155 AVFilterLink *inlink = outlink->src->inputs[0];
156 int ret;
157
158 ret = ff_request_frame(inlink);
159 if (ret == AVERROR_EOF) {
160 ret = push_samples(outlink);
161 return ret < 0 ? ret : ret > 0 ? 0 : AVERROR_EOF;
162 }
163
164 return ret;
165}
166
167static const AVFilterPad asetnsamples_inputs[] = {
168 {
169 .name = "default",
170 .type = AVMEDIA_TYPE_AUDIO,
171 .filter_frame = filter_frame,
172 },
173 { NULL }
174};
175
176static const AVFilterPad asetnsamples_outputs[] = {
177 {
178 .name = "default",
179 .type = AVMEDIA_TYPE_AUDIO,
180 .request_frame = request_frame,
181 .config_props = config_props_output,
182 },
183 { NULL }
184};
185
186AVFilter ff_af_asetnsamples = {
187 .name = "asetnsamples",
188 .description = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."),
189 .priv_size = sizeof(ASNSContext),
190 .priv_class = &asetnsamples_class,
191 .init = init,
192 .uninit = uninit,
193 .inputs = asetnsamples_inputs,
194 .outputs = asetnsamples_outputs,
195};
196
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