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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 | ||
36 | typedef 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 | ||
47 | static 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_INT, {.i64=1}, 0, 1, FLAGS }, | |
51 | { "p", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS }, | |
52 | { NULL } | |
53 | }; | |
54 | ||
55 | AVFILTER_DEFINE_CLASS(asetnsamples); | |
56 | ||
57 | static 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 | ||
67 | static av_cold void uninit(AVFilterContext *ctx) | |
68 | { | |
69 | ASNSContext *asns = ctx->priv; | |
70 | av_audio_fifo_free(asns->fifo); | |
71 | } | |
72 | ||
73 | static 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 | outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP; | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
85 | static int push_samples(AVFilterLink *outlink) | |
86 | { | |
87 | ASNSContext *asns = outlink->src->priv; | |
88 | AVFrame *outsamples = NULL; | |
89 | int ret, nb_out_samples, nb_pad_samples; | |
90 | ||
91 | if (asns->pad) { | |
92 | nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0; | |
93 | nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo)); | |
94 | } else { | |
95 | nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo)); | |
96 | nb_pad_samples = 0; | |
97 | } | |
98 | ||
99 | if (!nb_out_samples) | |
100 | return 0; | |
101 | ||
102 | outsamples = ff_get_audio_buffer(outlink, nb_out_samples); | |
103 | if (!outsamples) | |
104 | return AVERROR(ENOMEM); | |
105 | ||
106 | av_audio_fifo_read(asns->fifo, | |
107 | (void **)outsamples->extended_data, nb_out_samples); | |
108 | ||
109 | if (nb_pad_samples) | |
110 | av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples, | |
111 | nb_pad_samples, outlink->channels, | |
112 | outlink->format); | |
113 | outsamples->nb_samples = nb_out_samples; | |
114 | outsamples->channel_layout = outlink->channel_layout; | |
115 | outsamples->sample_rate = outlink->sample_rate; | |
116 | outsamples->pts = asns->next_out_pts; | |
117 | ||
118 | if (asns->next_out_pts != AV_NOPTS_VALUE) | |
119 | asns->next_out_pts += av_rescale_q(nb_out_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base); | |
120 | ||
121 | ret = ff_filter_frame(outlink, outsamples); | |
122 | if (ret < 0) | |
123 | return ret; | |
124 | return nb_out_samples; | |
125 | } | |
126 | ||
127 | static int filter_frame(AVFilterLink *inlink, AVFrame *insamples) | |
128 | { | |
129 | AVFilterContext *ctx = inlink->dst; | |
130 | ASNSContext *asns = ctx->priv; | |
131 | AVFilterLink *outlink = ctx->outputs[0]; | |
132 | int ret; | |
133 | int nb_samples = insamples->nb_samples; | |
134 | ||
135 | if (av_audio_fifo_space(asns->fifo) < nb_samples) { | |
136 | av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples); | |
137 | ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples); | |
138 | if (ret < 0) { | |
139 | av_log(ctx, AV_LOG_ERROR, | |
140 | "Stretching audio fifo failed, discarded %d samples\n", nb_samples); | |
141 | return -1; | |
142 | } | |
143 | } | |
144 | av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples); | |
145 | if (asns->next_out_pts == AV_NOPTS_VALUE) | |
146 | asns->next_out_pts = insamples->pts; | |
147 | av_frame_free(&insamples); | |
148 | ||
149 | while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples) | |
150 | push_samples(outlink); | |
151 | return 0; | |
152 | } | |
153 | ||
154 | static int request_frame(AVFilterLink *outlink) | |
155 | { | |
156 | AVFilterLink *inlink = outlink->src->inputs[0]; | |
157 | int ret; | |
158 | ||
159 | ret = ff_request_frame(inlink); | |
160 | if (ret == AVERROR_EOF) { | |
161 | ret = push_samples(outlink); | |
162 | return ret < 0 ? ret : ret > 0 ? 0 : AVERROR_EOF; | |
163 | } | |
164 | ||
165 | return ret; | |
166 | } | |
167 | ||
168 | static const AVFilterPad asetnsamples_inputs[] = { | |
169 | { | |
170 | .name = "default", | |
171 | .type = AVMEDIA_TYPE_AUDIO, | |
172 | .filter_frame = filter_frame, | |
173 | }, | |
174 | { NULL } | |
175 | }; | |
176 | ||
177 | static const AVFilterPad asetnsamples_outputs[] = { | |
178 | { | |
179 | .name = "default", | |
180 | .type = AVMEDIA_TYPE_AUDIO, | |
181 | .request_frame = request_frame, | |
182 | .config_props = config_props_output, | |
183 | }, | |
184 | { NULL } | |
185 | }; | |
186 | ||
187 | AVFilter ff_af_asetnsamples = { | |
188 | .name = "asetnsamples", | |
189 | .description = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."), | |
190 | .priv_size = sizeof(ASNSContext), | |
191 | .priv_class = &asetnsamples_class, | |
192 | .init = init, | |
193 | .uninit = uninit, | |
194 | .inputs = asetnsamples_inputs, | |
195 | .outputs = asetnsamples_outputs, | |
196 | }; |