3 * This file is part of Libav.
5 * Libav is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
10 * Libav is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with Libav; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 * sample format and channel layout conversion audio filter
25 #include "libavutil/avassert.h"
26 #include "libavutil/avstring.h"
27 #include "libavutil/mathematics.h"
28 #include "libavutil/opt.h"
30 #include "libavresample/avresample.h"
37 typedef struct ResampleContext {
38 AVAudioResampleContext *avr;
43 static av_cold void uninit(AVFilterContext *ctx)
45 ResampleContext *s = ctx->priv;
48 avresample_close(s->avr);
49 avresample_free(&s->avr);
53 static int query_formats(AVFilterContext *ctx)
55 AVFilterLink *inlink = ctx->inputs[0];
56 AVFilterLink *outlink = ctx->outputs[0];
58 AVFilterFormats *in_formats = ff_all_formats(AVMEDIA_TYPE_AUDIO);
59 AVFilterFormats *out_formats = ff_all_formats(AVMEDIA_TYPE_AUDIO);
60 AVFilterFormats *in_samplerates = ff_all_samplerates();
61 AVFilterFormats *out_samplerates = ff_all_samplerates();
62 AVFilterChannelLayouts *in_layouts = ff_all_channel_layouts();
63 AVFilterChannelLayouts *out_layouts = ff_all_channel_layouts();
65 ff_formats_ref(in_formats, &inlink->out_formats);
66 ff_formats_ref(out_formats, &outlink->in_formats);
68 ff_formats_ref(in_samplerates, &inlink->out_samplerates);
69 ff_formats_ref(out_samplerates, &outlink->in_samplerates);
71 ff_channel_layouts_ref(in_layouts, &inlink->out_channel_layouts);
72 ff_channel_layouts_ref(out_layouts, &outlink->in_channel_layouts);
77 static int config_output(AVFilterLink *outlink)
79 AVFilterContext *ctx = outlink->src;
80 AVFilterLink *inlink = ctx->inputs[0];
81 ResampleContext *s = ctx->priv;
82 char buf1[64], buf2[64];
86 avresample_close(s->avr);
87 avresample_free(&s->avr);
90 if (inlink->channel_layout == outlink->channel_layout &&
91 inlink->sample_rate == outlink->sample_rate &&
92 inlink->format == outlink->format)
95 if (!(s->avr = avresample_alloc_context()))
96 return AVERROR(ENOMEM);
98 av_opt_set_int(s->avr, "in_channel_layout", inlink ->channel_layout, 0);
99 av_opt_set_int(s->avr, "out_channel_layout", outlink->channel_layout, 0);
100 av_opt_set_int(s->avr, "in_sample_fmt", inlink ->format, 0);
101 av_opt_set_int(s->avr, "out_sample_fmt", outlink->format, 0);
102 av_opt_set_int(s->avr, "in_sample_rate", inlink ->sample_rate, 0);
103 av_opt_set_int(s->avr, "out_sample_rate", outlink->sample_rate, 0);
105 /* if both the input and output formats are s16 or u8, use s16 as
106 the internal sample format */
107 if (av_get_bytes_per_sample(inlink->format) <= 2 &&
108 av_get_bytes_per_sample(outlink->format) <= 2)
109 av_opt_set_int(s->avr, "internal_sample_fmt", AV_SAMPLE_FMT_S16P, 0);
111 if ((ret = avresample_open(s->avr)) < 0)
114 outlink->time_base = (AVRational){ 1, outlink->sample_rate };
115 s->next_pts = AV_NOPTS_VALUE;
117 av_get_channel_layout_string(buf1, sizeof(buf1),
118 -1, inlink ->channel_layout);
119 av_get_channel_layout_string(buf2, sizeof(buf2),
120 -1, outlink->channel_layout);
121 av_log(ctx, AV_LOG_VERBOSE,
122 "fmt:%s srate:%d cl:%s -> fmt:%s srate:%d cl:%s\n",
123 av_get_sample_fmt_name(inlink ->format), inlink ->sample_rate, buf1,
124 av_get_sample_fmt_name(outlink->format), outlink->sample_rate, buf2);
129 static int request_frame(AVFilterLink *outlink)
131 AVFilterContext *ctx = outlink->src;
132 ResampleContext *s = ctx->priv;
133 int ret = avfilter_request_frame(ctx->inputs[0]);
135 /* flush the lavr delay buffer */
136 if (ret == AVERROR_EOF && s->avr) {
137 AVFilterBufferRef *buf;
138 int nb_samples = av_rescale_rnd(avresample_get_delay(s->avr),
139 outlink->sample_rate,
140 ctx->inputs[0]->sample_rate,
146 buf = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
148 return AVERROR(ENOMEM);
150 ret = avresample_convert(s->avr, (void**)buf->extended_data,
151 buf->linesize[0], nb_samples,
154 avfilter_unref_buffer(buf);
155 return (ret == 0) ? AVERROR_EOF : ret;
158 buf->pts = s->next_pts;
159 ff_filter_samples(outlink, buf);
165 static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
167 AVFilterContext *ctx = inlink->dst;
168 ResampleContext *s = ctx->priv;
169 AVFilterLink *outlink = ctx->outputs[0];
172 AVFilterBufferRef *buf_out;
173 int delay, nb_samples, ret;
175 /* maximum possible samples lavr can output */
176 delay = avresample_get_delay(s->avr);
177 nb_samples = av_rescale_rnd(buf->audio->nb_samples + delay,
178 outlink->sample_rate, inlink->sample_rate,
181 buf_out = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
182 ret = avresample_convert(s->avr, (void**)buf_out->extended_data,
183 buf_out->linesize[0], nb_samples,
184 (void**)buf->extended_data, buf->linesize[0],
185 buf->audio->nb_samples);
187 av_assert0(!avresample_available(s->avr));
189 if (s->next_pts == AV_NOPTS_VALUE) {
190 if (buf->pts == AV_NOPTS_VALUE) {
191 av_log(ctx, AV_LOG_WARNING, "First timestamp is missing, "
195 s->next_pts = av_rescale_q(buf->pts, inlink->time_base,
200 buf_out->audio->nb_samples = ret;
201 if (buf->pts != AV_NOPTS_VALUE) {
202 buf_out->pts = av_rescale_q(buf->pts, inlink->time_base,
203 outlink->time_base) -
204 av_rescale(delay, outlink->sample_rate,
205 inlink->sample_rate);
207 buf_out->pts = s->next_pts;
209 s->next_pts = buf_out->pts + buf_out->audio->nb_samples;
211 ff_filter_samples(outlink, buf_out);
213 avfilter_unref_buffer(buf);
215 ff_filter_samples(outlink, buf);
218 AVFilter avfilter_af_resample = {
220 .description = NULL_IF_CONFIG_SMALL("Audio resampling and conversion."),
221 .priv_size = sizeof(ResampleContext),
224 .query_formats = query_formats,
226 .inputs = (const AVFilterPad[]) {{ .name = "default",
227 .type = AVMEDIA_TYPE_AUDIO,
228 .filter_samples = filter_samples,
229 .min_perms = AV_PERM_READ },
231 .outputs = (const AVFilterPad[]) {{ .name = "default",
232 .type = AVMEDIA_TYPE_AUDIO,
233 .config_props = config_output,
234 .request_frame = request_frame },