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/audioconvert.h"
29 #include "libavutil/avassert.h"
30 #include "libavutil/opt.h"
38 int nb_out_samples; ///< how many samples to output
39 AVAudioFifo *fifo; ///< samples are queued here
45 #define OFFSET(x) offsetof(ASNSContext, x)
46 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
48 static const AVOption asetnsamples_options[] = {
49 { "pad", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
50 { "p", "pad last frame with zeros", OFFSET(pad), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS },
51 { "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 },
52 { "n", "set the number of per-frame output samples", OFFSET(nb_out_samples), AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX, FLAGS },
56 AVFILTER_DEFINE_CLASS(asetnsamples);
58 static av_cold int init(AVFilterContext *ctx, const char *args)
60 ASNSContext *asns = ctx->priv;
63 asns->class = &asetnsamples_class;
64 av_opt_set_defaults(asns);
66 if ((err = av_set_options_string(asns, args, "=", ":")) < 0)
69 asns->next_out_pts = AV_NOPTS_VALUE;
70 av_log(ctx, AV_LOG_VERBOSE, "nb_out_samples:%d pad:%d\n", asns->nb_out_samples, asns->pad);
75 static av_cold void uninit(AVFilterContext *ctx)
77 ASNSContext *asns = ctx->priv;
78 av_audio_fifo_free(asns->fifo);
81 static int config_props_output(AVFilterLink *outlink)
83 ASNSContext *asns = outlink->src->priv;
84 int nb_channels = av_get_channel_layout_nb_channels(outlink->channel_layout);
86 asns->fifo = av_audio_fifo_alloc(outlink->format, nb_channels, asns->nb_out_samples);
88 return AVERROR(ENOMEM);
93 static int push_samples(AVFilterLink *outlink)
95 ASNSContext *asns = outlink->src->priv;
96 AVFilterBufferRef *outsamples = NULL;
97 int nb_out_samples, nb_pad_samples;
100 nb_out_samples = av_audio_fifo_size(asns->fifo) ? asns->nb_out_samples : 0;
101 nb_pad_samples = nb_out_samples - FFMIN(nb_out_samples, av_audio_fifo_size(asns->fifo));
103 nb_out_samples = FFMIN(asns->nb_out_samples, av_audio_fifo_size(asns->fifo));
110 outsamples = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_out_samples);
111 av_assert0(outsamples);
113 av_audio_fifo_read(asns->fifo,
114 (void **)outsamples->extended_data, nb_out_samples);
117 av_samples_set_silence(outsamples->extended_data, nb_out_samples - nb_pad_samples,
118 nb_pad_samples, av_get_channel_layout_nb_channels(outlink->channel_layout),
120 outsamples->audio->nb_samples = nb_out_samples;
121 outsamples->audio->channel_layout = outlink->channel_layout;
122 outsamples->audio->sample_rate = outlink->sample_rate;
123 outsamples->pts = asns->next_out_pts;
125 if (asns->next_out_pts != AV_NOPTS_VALUE)
126 asns->next_out_pts += nb_out_samples;
128 ff_filter_samples(outlink, outsamples);
129 asns->req_fullfilled = 1;
130 return nb_out_samples;
133 static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
135 AVFilterContext *ctx = inlink->dst;
136 ASNSContext *asns = ctx->priv;
137 AVFilterLink *outlink = ctx->outputs[0];
139 int nb_samples = insamples->audio->nb_samples;
141 if (av_audio_fifo_space(asns->fifo) < nb_samples) {
142 av_log(ctx, AV_LOG_DEBUG, "No space for %d samples, stretching audio fifo\n", nb_samples);
143 ret = av_audio_fifo_realloc(asns->fifo, av_audio_fifo_size(asns->fifo) + nb_samples);
145 av_log(ctx, AV_LOG_ERROR,
146 "Stretching audio fifo failed, discarded %d samples\n", nb_samples);
150 av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
151 if (asns->next_out_pts == AV_NOPTS_VALUE)
152 asns->next_out_pts = insamples->pts;
153 avfilter_unref_buffer(insamples);
155 while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)
156 push_samples(outlink);
160 static int request_frame(AVFilterLink *outlink)
162 ASNSContext *asns = outlink->src->priv;
163 AVFilterLink *inlink = outlink->src->inputs[0];
166 asns->req_fullfilled = 0;
168 ret = ff_request_frame(inlink);
169 } while (!asns->req_fullfilled && ret >= 0);
171 if (ret == AVERROR_EOF)
172 while (push_samples(outlink))
178 AVFilter avfilter_af_asetnsamples = {
179 .name = "asetnsamples",
180 .description = NULL_IF_CONFIG_SMALL("Set the number of samples for each output audio frames."),
181 .priv_size = sizeof(ASNSContext),
185 .inputs = (const AVFilterPad[]) {
188 .type = AVMEDIA_TYPE_AUDIO,
189 .filter_samples = filter_samples,
190 .min_perms = AV_PERM_READ|AV_PERM_WRITE
195 .outputs = (const AVFilterPad[]) {
198 .type = AVMEDIA_TYPE_AUDIO,
199 .request_frame = request_frame,
200 .config_props = config_props_output,
204 .priv_class = &asetnsamples_class,