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"
36 typedef struct ASNSContext {
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_BOOL, {.i64=1}, 0, 1, FLAGS },
51 { "p", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_BOOL, {.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;
77 asns->fifo = av_audio_fifo_alloc(outlink->format, outlink->channels, asns->nb_out_samples);
79 return AVERROR(ENOMEM);
84 static int push_samples(AVFilterLink *outlink)
86 ASNSContext *asns = outlink->src->priv;
87 AVFrame *outsamples = NULL;
88 int ret, nb_out_samples, nb_pad_samples;
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));
94 nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo));
101 outsamples = ff_get_audio_buffer(outlink, nb_out_samples);
103 return AVERROR(ENOMEM);
105 av_audio_fifo_read(asns->fifo,
106 (void **)outsamples->extended_data, nb_out_samples);
109 av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples,
110 nb_pad_samples, outlink->channels,
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;
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);
120 ret = ff_filter_frame(outlink, outsamples);
123 return nb_out_samples;
126 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
128 AVFilterContext *ctx = inlink->dst;
129 ASNSContext *asns = ctx->priv;
130 AVFilterLink *outlink = ctx->outputs[0];
132 int nb_samples = insamples->nb_samples;
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);
138 av_log(ctx, AV_LOG_ERROR,
139 "Stretching audio fifo failed, discarded %d samples\n", nb_samples);
143 ret = av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
144 if (ret > 0 && asns->next_out_pts == AV_NOPTS_VALUE)
145 asns->next_out_pts = insamples->pts;
146 av_frame_free(&insamples);
151 while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)
152 push_samples(outlink);
156 static int request_frame(AVFilterLink *outlink)
158 AVFilterLink *inlink = outlink->src->inputs[0];
161 ret = ff_request_frame(inlink);
162 if (ret == AVERROR_EOF) {
163 ret = push_samples(outlink);
164 return ret < 0 ? ret : ret > 0 ? 0 : AVERROR_EOF;
170 static const AVFilterPad asetnsamples_inputs[] = {
173 .type = AVMEDIA_TYPE_AUDIO,
174 .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 ff_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),
193 .priv_class = &asetnsamples_class,
196 .inputs = asetnsamples_inputs,
197 .outputs = asetnsamples_outputs,