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;
42 /* set by filter_samples() to signal an output frame to request_frame() */
46 static av_cold void uninit(AVFilterContext *ctx)
48 ResampleContext *s = ctx->priv;
51 avresample_close(s->avr);
52 avresample_free(&s->avr);
56 static int query_formats(AVFilterContext *ctx)
58 AVFilterLink *inlink = ctx->inputs[0];
59 AVFilterLink *outlink = ctx->outputs[0];
61 AVFilterFormats *in_formats = ff_all_formats(AVMEDIA_TYPE_AUDIO);
62 AVFilterFormats *out_formats = ff_all_formats(AVMEDIA_TYPE_AUDIO);
63 AVFilterFormats *in_samplerates = ff_all_samplerates();
64 AVFilterFormats *out_samplerates = ff_all_samplerates();
65 AVFilterChannelLayouts *in_layouts = ff_all_channel_layouts();
66 AVFilterChannelLayouts *out_layouts = ff_all_channel_layouts();
68 ff_formats_ref(in_formats, &inlink->out_formats);
69 ff_formats_ref(out_formats, &outlink->in_formats);
71 ff_formats_ref(in_samplerates, &inlink->out_samplerates);
72 ff_formats_ref(out_samplerates, &outlink->in_samplerates);
74 ff_channel_layouts_ref(in_layouts, &inlink->out_channel_layouts);
75 ff_channel_layouts_ref(out_layouts, &outlink->in_channel_layouts);
80 static int config_output(AVFilterLink *outlink)
82 AVFilterContext *ctx = outlink->src;
83 AVFilterLink *inlink = ctx->inputs[0];
84 ResampleContext *s = ctx->priv;
85 char buf1[64], buf2[64];
89 avresample_close(s->avr);
90 avresample_free(&s->avr);
93 if (inlink->channel_layout == outlink->channel_layout &&
94 inlink->sample_rate == outlink->sample_rate &&
95 inlink->format == outlink->format)
98 if (!(s->avr = avresample_alloc_context()))
99 return AVERROR(ENOMEM);
101 av_opt_set_int(s->avr, "in_channel_layout", inlink ->channel_layout, 0);
102 av_opt_set_int(s->avr, "out_channel_layout", outlink->channel_layout, 0);
103 av_opt_set_int(s->avr, "in_sample_fmt", inlink ->format, 0);
104 av_opt_set_int(s->avr, "out_sample_fmt", outlink->format, 0);
105 av_opt_set_int(s->avr, "in_sample_rate", inlink ->sample_rate, 0);
106 av_opt_set_int(s->avr, "out_sample_rate", outlink->sample_rate, 0);
108 if ((ret = avresample_open(s->avr)) < 0)
111 outlink->time_base = (AVRational){ 1, outlink->sample_rate };
112 s->next_pts = AV_NOPTS_VALUE;
114 av_get_channel_layout_string(buf1, sizeof(buf1),
115 -1, inlink ->channel_layout);
116 av_get_channel_layout_string(buf2, sizeof(buf2),
117 -1, outlink->channel_layout);
118 av_log(ctx, AV_LOG_VERBOSE,
119 "fmt:%s srate:%d cl:%s -> fmt:%s srate:%d cl:%s\n",
120 av_get_sample_fmt_name(inlink ->format), inlink ->sample_rate, buf1,
121 av_get_sample_fmt_name(outlink->format), outlink->sample_rate, buf2);
126 static int request_frame(AVFilterLink *outlink)
128 AVFilterContext *ctx = outlink->src;
129 ResampleContext *s = ctx->priv;
133 while (ret >= 0 && !s->got_output)
134 ret = ff_request_frame(ctx->inputs[0]);
136 /* flush the lavr delay buffer */
137 if (ret == AVERROR_EOF && s->avr) {
138 AVFilterBufferRef *buf;
139 int nb_samples = av_rescale_rnd(avresample_get_delay(s->avr),
140 outlink->sample_rate,
141 ctx->inputs[0]->sample_rate,
147 buf = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
149 return AVERROR(ENOMEM);
151 ret = avresample_convert(s->avr, (void**)buf->extended_data,
152 buf->linesize[0], nb_samples,
155 avfilter_unref_buffer(buf);
156 return (ret == 0) ? AVERROR_EOF : ret;
159 buf->pts = s->next_pts;
160 return ff_filter_samples(outlink, buf);
165 static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
167 AVFilterContext *ctx = inlink->dst;
168 ResampleContext *s = ctx->priv;
169 AVFilterLink *outlink = ctx->outputs[0];
173 AVFilterBufferRef *buf_out;
174 int delay, nb_samples;
176 /* maximum possible samples lavr can output */
177 delay = avresample_get_delay(s->avr);
178 nb_samples = av_rescale_rnd(buf->audio->nb_samples + delay,
179 outlink->sample_rate, inlink->sample_rate,
182 buf_out = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
184 ret = AVERROR(ENOMEM);
188 ret = avresample_convert(s->avr, (void**)buf_out->extended_data,
189 buf_out->linesize[0], nb_samples,
190 (void**)buf->extended_data, buf->linesize[0],
191 buf->audio->nb_samples);
193 avfilter_unref_buffer(buf_out);
197 av_assert0(!avresample_available(s->avr));
199 if (s->next_pts == AV_NOPTS_VALUE) {
200 if (buf->pts == AV_NOPTS_VALUE) {
201 av_log(ctx, AV_LOG_WARNING, "First timestamp is missing, "
205 s->next_pts = av_rescale_q(buf->pts, inlink->time_base,
210 buf_out->audio->nb_samples = ret;
211 if (buf->pts != AV_NOPTS_VALUE) {
212 buf_out->pts = av_rescale_q(buf->pts, inlink->time_base,
213 outlink->time_base) -
214 av_rescale(delay, outlink->sample_rate,
215 inlink->sample_rate);
217 buf_out->pts = s->next_pts;
219 s->next_pts = buf_out->pts + buf_out->audio->nb_samples;
221 ret = ff_filter_samples(outlink, buf_out);
226 avfilter_unref_buffer(buf);
228 ret = ff_filter_samples(outlink, buf);
235 AVFilter avfilter_af_resample = {
237 .description = NULL_IF_CONFIG_SMALL("Audio resampling and conversion."),
238 .priv_size = sizeof(ResampleContext),
241 .query_formats = query_formats,
243 .inputs = (const AVFilterPad[]) {{ .name = "default",
244 .type = AVMEDIA_TYPE_AUDIO,
245 .filter_samples = filter_samples,
246 .min_perms = AV_PERM_READ },
248 .outputs = (const AVFilterPad[]) {{ .name = "default",
249 .type = AVMEDIA_TYPE_AUDIO,
250 .config_props = config_output,
251 .request_frame = request_frame },