2 * Copyright (c) 2013 Nicolas George
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public License
8 * as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #include "libavutil/opt.h"
25 typedef struct ASetRateContext {
31 #define CONTEXT ASetRateContext
32 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
34 #define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \
35 { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type, \
36 { .deffield = def }, min, max, FLAGS, __VA_ARGS__ }
38 #define OPT_INT(name, field, def, min, max, descr, ...) \
39 OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__)
41 static const AVOption asetrate_options[] = {
42 OPT_INT("sample_rate", sample_rate, 44100, 1, INT_MAX, "set the sample rate",),
43 OPT_INT("r", sample_rate, 44100, 1, INT_MAX, "set the sample rate",),
47 AVFILTER_DEFINE_CLASS(asetrate);
49 static av_cold int query_formats(AVFilterContext *ctx)
51 ASetRateContext *sr = ctx->priv;
52 int sample_rates[] = { sr->sample_rate, -1 };
54 return ff_formats_ref(ff_make_format_list(sample_rates),
55 &ctx->outputs[0]->incfg.samplerates);
58 static av_cold int config_props(AVFilterLink *outlink)
60 AVFilterContext *ctx = outlink->src;
61 ASetRateContext *sr = ctx->priv;
62 AVFilterLink *inlink = ctx->inputs[0];
63 AVRational intb = ctx->inputs[0]->time_base;
64 int inrate = inlink->sample_rate;
66 if (intb.num == 1 && intb.den == inrate) {
67 outlink->time_base.num = 1;
68 outlink->time_base.den = outlink->sample_rate;
70 outlink->time_base = intb;
72 if (av_q2d(intb) > 1.0 / FFMAX(inrate, outlink->sample_rate))
73 av_log(ctx, AV_LOG_WARNING, "Time base is inaccurate\n");
78 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
80 AVFilterContext *ctx = inlink->dst;
81 ASetRateContext *sr = ctx->priv;
82 AVFilterLink *outlink = ctx->outputs[0];
84 frame->sample_rate = outlink->sample_rate;
86 frame->pts = av_rescale(frame->pts, inlink->sample_rate,
87 outlink->sample_rate);
88 return ff_filter_frame(outlink, frame);
91 static const AVFilterPad asetrate_inputs[] = {
94 .type = AVMEDIA_TYPE_AUDIO,
95 .filter_frame = filter_frame,
100 static const AVFilterPad asetrate_outputs[] = {
103 .type = AVMEDIA_TYPE_AUDIO,
104 .config_props = config_props,
109 AVFilter ff_af_asetrate = {
111 .description = NULL_IF_CONFIG_SMALL("Change the sample rate without "
112 "altering the data."),
113 .query_formats = query_formats,
114 .priv_size = sizeof(ASetRateContext),
115 .inputs = asetrate_inputs,
116 .outputs = asetrate_outputs,
117 .priv_class = &asetrate_class,