2 * Copyright (c) 2011 Stefano Sabatini
3 * Copyright (c) 2011 Mina Nagy Zaki
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 * resampling audio filter
27 #include "libswresample/swresample.h"
35 struct SwrContext *swr;
38 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
40 AResampleContext *aresample = ctx->priv;
44 if ((ret = ff_parse_sample_rate(&aresample->out_rate, args, ctx)) < 0)
47 aresample->out_rate = -1;
53 static av_cold void uninit(AVFilterContext *ctx)
55 AResampleContext *aresample = ctx->priv;
56 swr_free(&aresample->swr);
59 static int query_formats(AVFilterContext *ctx)
61 AResampleContext *aresample = ctx->priv;
63 AVFilterLink *inlink = ctx->inputs[0];
64 AVFilterLink *outlink = ctx->outputs[0];
66 AVFilterFormats *in_formats = avfilter_all_formats(AVMEDIA_TYPE_AUDIO);
67 AVFilterFormats *out_formats = avfilter_all_formats(AVMEDIA_TYPE_AUDIO);
68 AVFilterFormats *in_samplerates = ff_all_samplerates();
69 AVFilterFormats *out_samplerates;
72 AVFilterChannelLayouts *in_layouts = ff_all_channel_layouts();
73 AVFilterChannelLayouts *out_layouts = ff_all_channel_layouts();
75 avfilter_formats_ref(in_formats, &inlink->out_formats);
76 avfilter_formats_ref(out_formats, &outlink->in_formats);
78 avfilter_formats_ref(in_samplerates, &inlink->out_samplerates);
80 ff_channel_layouts_ref(in_layouts, &inlink->out_channel_layouts);
81 ff_channel_layouts_ref(out_layouts, &outlink->in_channel_layouts);
83 if(aresample->out_rate > 0) {
84 int sample_rates[] = { aresample->out_rate, -1 };
85 ff_set_common_samplerates(ctx, avfilter_make_format_list(sample_rates));
87 out_samplerates = ff_all_samplerates();
88 avfilter_formats_ref(out_samplerates, &outlink->in_samplerates);
95 static int config_output(AVFilterLink *outlink)
98 AVFilterContext *ctx = outlink->src;
99 AVFilterLink *inlink = ctx->inputs[0];
100 AResampleContext *aresample = ctx->priv;
102 if (aresample->out_rate == -1)
103 aresample->out_rate = outlink->sample_rate;
105 outlink->sample_rate = aresample->out_rate;
106 outlink->time_base = (AVRational) {1, aresample->out_rate};
108 //TODO: make the resampling parameters (filter size, phrase shift, linear, cutoff) configurable
109 aresample->swr = swr_alloc_set_opts(aresample->swr,
110 outlink->channel_layout, outlink->format, outlink->sample_rate,
111 inlink->channel_layout, inlink->format, inlink->sample_rate,
114 return AVERROR(ENOMEM);
115 ret = swr_init(aresample->swr);
119 aresample->ratio = (double)outlink->sample_rate / inlink->sample_rate;
121 av_log(ctx, AV_LOG_INFO, "r:%"PRId64"Hz -> r:%"PRId64"Hz\n",
122 inlink->sample_rate, outlink->sample_rate);
126 static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamplesref)
128 AResampleContext *aresample = inlink->dst->priv;
129 const int n_in = insamplesref->audio->nb_samples;
130 int n_out = n_in * aresample->ratio;
131 AVFilterLink *const outlink = inlink->dst->outputs[0];
132 AVFilterBufferRef *outsamplesref = ff_get_audio_buffer(outlink, AV_PERM_WRITE, n_out);
134 n_out = swr_convert(aresample->swr, outsamplesref->data, n_out,
135 (void *)insamplesref->data, n_in);
137 avfilter_copy_buffer_ref_props(outsamplesref, insamplesref);
138 outsamplesref->audio->sample_rate = outlink->sample_rate;
139 outsamplesref->audio->nb_samples = n_out;
140 outsamplesref->pts = insamplesref->pts == AV_NOPTS_VALUE ? AV_NOPTS_VALUE :
141 av_rescale(outlink->sample_rate, insamplesref->pts, inlink ->sample_rate);
143 ff_filter_samples(outlink, outsamplesref);
144 avfilter_unref_buffer(insamplesref);
147 AVFilter avfilter_af_aresample = {
149 .description = NULL_IF_CONFIG_SMALL("Resample audio data."),
152 .query_formats = query_formats,
153 .priv_size = sizeof(AResampleContext),
155 .inputs = (const AVFilterPad[]) {{ .name = "default",
156 .type = AVMEDIA_TYPE_AUDIO,
157 .filter_samples = filter_samples,
158 .min_perms = AV_PERM_READ, },
160 .outputs = (const AVFilterPad[]) {{ .name = "default",
161 .config_props = config_output,
162 .type = AVMEDIA_TYPE_AUDIO, },