2 * Copyright (c) 2012 Andrey Utkin
3 * Copyright (c) 2012 Stefano Sabatini
5 * This file is part of FFmpeg.
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.
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.
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
24 * Filter that changes number of samples on single output operation
27 #include "libavutil/audio_fifo.h"
28 #include "libavutil/avassert.h"
29 #include "libavutil/channel_layout.h"
30 #include "libavutil/opt.h"
38 int nb_out_samples; ///< how many samples to output
39 AVAudioFifo *fifo; ///< samples are queued here
44 #define OFFSET(x) offsetof(ASNSContext, x)
45 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
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 },
55 AVFILTER_DEFINE_CLASS(asetnsamples);
57 static av_cold int init(AVFilterContext *ctx)
59 ASNSContext *asns = ctx->priv;
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);
67 static av_cold void uninit(AVFilterContext *ctx)
69 ASNSContext *asns = ctx->priv;
70 av_audio_fifo_free(asns->fifo);
73 static int config_props_output(AVFilterLink *outlink)
75 ASNSContext *asns = outlink->src->priv;
76 int nb_channels = av_get_channel_layout_nb_channels(outlink->channel_layout);
78 asns->fifo = av_audio_fifo_alloc(outlink->format, nb_channels, asns->nb_out_samples);
80 return AVERROR(ENOMEM);
81 outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
86 static int push_samples(AVFilterLink *outlink)
88 ASNSContext *asns = outlink->src->priv;
89 AVFrame *outsamples = NULL;
90 int ret, nb_out_samples, nb_pad_samples;
93 nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0;
94 nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo));
96 nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo));
103 outsamples = ff_get_audio_buffer(outlink, nb_out_samples);
105 return AVERROR(ENOMEM);
107 av_audio_fifo_read(asns->fifo,
108 (void **)outsamples->extended_data, nb_out_samples);
111 av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples,
112 nb_pad_samples, av_get_channel_layout_nb_channels(outlink->channel_layout),
114 outsamples->nb_samples = nb_out_samples;
115 outsamples->channel_layout = outlink->channel_layout;
116 outsamples->sample_rate = outlink->sample_rate;
117 outsamples->pts = asns->next_out_pts;
119 if (asns->next_out_pts != AV_NOPTS_VALUE)
120 asns->next_out_pts += nb_out_samples;
122 ret = ff_filter_frame(outlink, outsamples);
125 return nb_out_samples;
128 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
130 AVFilterContext *ctx = inlink->dst;
131 ASNSContext *asns = ctx->priv;
132 AVFilterLink *outlink = ctx->outputs[0];
134 int nb_samples = insamples->nb_samples;
136 if (av_audio_fifo_space(asns->fifo) < nb_samples) {
137 av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples);
138 ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples);
140 av_log(ctx, AV_LOG_ERROR,
141 "Stretching audio fifo failed, discarded %d samples\n", nb_samples);
145 av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
146 if (asns->next_out_pts == AV_NOPTS_VALUE)
147 asns->next_out_pts = insamples->pts;
148 av_frame_free(&insamples);
150 while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)
151 push_samples(outlink);
155 static int request_frame(AVFilterLink *outlink)
157 AVFilterLink *inlink = outlink->src->inputs[0];
160 ret = ff_request_frame(inlink);
161 if (ret == AVERROR_EOF) {
162 ret = push_samples(outlink);
163 return ret < 0 ? ret : ret > 0 ? 0 : AVERROR_EOF;
169 static const AVFilterPad asetnsamples_inputs[] = {
172 .type = AVMEDIA_TYPE_AUDIO,
173 .filter_frame = filter_frame,
179 static const AVFilterPad asetnsamples_outputs[] = {
182 .type = AVMEDIA_TYPE_AUDIO,
183 .request_frame = request_frame,
184 .config_props = config_props_output,
189 AVFilter avfilter_af_asetnsamples = {
190 .name = "asetnsamples",
191 .description = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."),
192 .priv_size = sizeof(ASNSContext),
195 .inputs = asetnsamples_inputs,
196 .outputs = asetnsamples_outputs,
197 .priv_class = &asetnsamples_class,