libavfilter/af_resample.c

   1 /*
   2  *
   3  * This file is part of Libav.
   4  *
   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.
   9  *
  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.
  14  *
  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
  18  */
  19
  20 /**
  21  * @file
  22  * sample format and channel layout conversion audio filter
  23  */
  24
  25 #include "libavutil/avassert.h"
  26 #include "libavutil/avstring.h"
  27 #include "libavutil/common.h"
  28 #include "libavutil/mathematics.h"
  29 #include "libavutil/opt.h"
  30
  31 #include "libavresample/avresample.h"
  32
  33 #include "audio.h"
  34 #include "avfilter.h"
  35 #include "formats.h"
  36 #include "internal.h"
  37
  38 typedef struct ResampleContext {
  39     AVAudioResampleContext *avr;
  40
  41     int64_t next_pts;
  42
  43     /* set by filter_frame() to signal an output frame to request_frame() */
  44     int got_output;
  45 } ResampleContext;
  46
  47 static av_cold void uninit(AVFilterContext *ctx)
  48 {
  49     ResampleContext *s = ctx->priv;
  50
  51     if (s->avr) {
  52         avresample_close(s->avr);
  53         avresample_free(&s->avr);
  54     }
  55 }
  56
  57 static int query_formats(AVFilterContext *ctx)
  58 {
  59     AVFilterLink *inlink  = ctx->inputs[0];
  60     AVFilterLink *outlink = ctx->outputs[0];
  61
  62     AVFilterFormats        *in_formats      = ff_all_formats(AVMEDIA_TYPE_AUDIO);
  63     AVFilterFormats        *out_formats     = ff_all_formats(AVMEDIA_TYPE_AUDIO);
  64     AVFilterFormats        *in_samplerates  = ff_all_samplerates();
  65     AVFilterFormats        *out_samplerates = ff_all_samplerates();
  66     AVFilterChannelLayouts *in_layouts      = ff_all_channel_layouts();
  67     AVFilterChannelLayouts *out_layouts     = ff_all_channel_layouts();
  68
  69     ff_formats_ref(in_formats,  &inlink->out_formats);
  70     ff_formats_ref(out_formats, &outlink->in_formats);
  71
  72     ff_formats_ref(in_samplerates,  &inlink->out_samplerates);
  73     ff_formats_ref(out_samplerates, &outlink->in_samplerates);
  74
  75     ff_channel_layouts_ref(in_layouts,  &inlink->out_channel_layouts);
  76     ff_channel_layouts_ref(out_layouts, &outlink->in_channel_layouts);
  77
  78     return 0;
  79 }
  80
  81 static int config_output(AVFilterLink *outlink)
  82 {
  83     AVFilterContext *ctx = outlink->src;
  84     AVFilterLink *inlink = ctx->inputs[0];
  85     ResampleContext   *s = ctx->priv;
  86     char buf1[64], buf2[64];
  87     int ret;
  88
  89     if (s->avr) {
  90         avresample_close(s->avr);
  91         avresample_free(&s->avr);
  92     }
  93
  94     if (inlink->channel_layout == outlink->channel_layout &&
  95         inlink->sample_rate    == outlink->sample_rate    &&
  96         (inlink->format        == outlink->format ||
  97         (av_get_channel_layout_nb_channels(inlink->channel_layout)  == 1 &&
  98          av_get_channel_layout_nb_channels(outlink->channel_layout) == 1 &&
  99          av_get_planar_sample_fmt(inlink->format) ==
 100          av_get_planar_sample_fmt(outlink->format))))
 101         return 0;
 102
 103     if (!(s->avr = avresample_alloc_context()))
 104         return AVERROR(ENOMEM);
 105
 106     av_opt_set_int(s->avr,  "in_channel_layout", inlink ->channel_layout, 0);
 107     av_opt_set_int(s->avr, "out_channel_layout", outlink->channel_layout, 0);
 108     av_opt_set_int(s->avr,  "in_sample_fmt",     inlink ->format,         0);
 109     av_opt_set_int(s->avr, "out_sample_fmt",     outlink->format,         0);
 110     av_opt_set_int(s->avr,  "in_sample_rate",    inlink ->sample_rate,    0);
 111     av_opt_set_int(s->avr, "out_sample_rate",    outlink->sample_rate,    0);
 112
 113     if ((ret = avresample_open(s->avr)) < 0)
 114         return ret;
 115
 116     outlink->time_base = (AVRational){ 1, outlink->sample_rate };
 117     s->next_pts        = AV_NOPTS_VALUE;
 118
 119     av_get_channel_layout_string(buf1, sizeof(buf1),
 120                                  -1, inlink ->channel_layout);
 121     av_get_channel_layout_string(buf2, sizeof(buf2),
 122                                  -1, outlink->channel_layout);
 123     av_log(ctx, AV_LOG_VERBOSE,
 124            "fmt:%s srate:%d cl:%s -> fmt:%s srate:%d cl:%s\n",
 125            av_get_sample_fmt_name(inlink ->format), inlink ->sample_rate, buf1,
 126            av_get_sample_fmt_name(outlink->format), outlink->sample_rate, buf2);
 127
 128     return 0;
 129 }
 130
 131 static int request_frame(AVFilterLink *outlink)
 132 {
 133     AVFilterContext *ctx = outlink->src;
 134     ResampleContext   *s = ctx->priv;
 135     int ret = 0;
 136
 137     s->got_output = 0;
 138     while (ret >= 0 && !s->got_output)
 139         ret = ff_request_frame(ctx->inputs[0]);
 140
 141     /* flush the lavr delay buffer */
 142     if (ret == AVERROR_EOF && s->avr) {
 143         AVFilterBufferRef *buf;
 144         int nb_samples = av_rescale_rnd(avresample_get_delay(s->avr),
 145                                         outlink->sample_rate,
 146                                         ctx->inputs[0]->sample_rate,
 147                                         AV_ROUND_UP);
 148
 149         if (!nb_samples)
 150             return ret;
 151
 152         buf = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
 153         if (!buf)
 154             return AVERROR(ENOMEM);
 155
 156         ret = avresample_convert(s->avr, buf->extended_data,
 157                                  buf->linesize[0], nb_samples,
 158                                  NULL, 0, 0);
 159         if (ret <= 0) {
 160             avfilter_unref_buffer(buf);
 161             return (ret == 0) ? AVERROR_EOF : ret;
 162         }
 163
 164         buf->pts = s->next_pts;
 165         return ff_filter_frame(outlink, buf);
 166     }
 167     return ret;
 168 }
 169
 170 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)
 171 {
 172     AVFilterContext  *ctx = inlink->dst;
 173     ResampleContext    *s = ctx->priv;
 174     AVFilterLink *outlink = ctx->outputs[0];
 175     int ret;
 176
 177     if (s->avr) {
 178         AVFilterBufferRef *buf_out;
 179         int delay, nb_samples;
 180
 181         /* maximum possible samples lavr can output */
 182         delay      = avresample_get_delay(s->avr);
 183         nb_samples = av_rescale_rnd(buf->audio->nb_samples + delay,
 184                                     outlink->sample_rate, inlink->sample_rate,
 185                                     AV_ROUND_UP);
 186
 187         buf_out = ff_get_audio_buffer(outlink, AV_PERM_WRITE, nb_samples);
 188         if (!buf_out) {
 189             ret = AVERROR(ENOMEM);
 190             goto fail;
 191         }
 192
 193         ret     = avresample_convert(s->avr, buf_out->extended_data,
 194                                      buf_out->linesize[0], nb_samples,
 195                                      buf->extended_data, buf->linesize[0],
 196                                      buf->audio->nb_samples);
 197         if (ret <= 0) {
 198             avfilter_unref_buffer(buf_out);
 199             if (ret < 0)
 200                 goto fail;
 201         }
 202
 203         av_assert0(!avresample_available(s->avr));
 204
 205         if (s->next_pts == AV_NOPTS_VALUE) {
 206             if (buf->pts == AV_NOPTS_VALUE) {
 207                 av_log(ctx, AV_LOG_WARNING, "First timestamp is missing, "
 208                        "assuming 0.\n");
 209                 s->next_pts = 0;
 210             } else
 211                 s->next_pts = av_rescale_q(buf->pts, inlink->time_base,
 212                                            outlink->time_base);
 213         }
 214
 215         if (ret > 0) {
 216             buf_out->audio->nb_samples = ret;
 217             if (buf->pts != AV_NOPTS_VALUE) {
 218                 buf_out->pts = av_rescale_q(buf->pts, inlink->time_base,
 219                                             outlink->time_base) -
 220                                av_rescale(delay, outlink->sample_rate,
 221                                           inlink->sample_rate);
 222             } else
 223                 buf_out->pts = s->next_pts;
 224
 225             s->next_pts = buf_out->pts + buf_out->audio->nb_samples;
 226
 227             ret = ff_filter_frame(outlink, buf_out);
 228             s->got_output = 1;
 229         }
 230
 231 fail:
 232         avfilter_unref_buffer(buf);
 233     } else {
 234         buf->format = outlink->format;
 235         ret = ff_filter_frame(outlink, buf);
 236         s->got_output = 1;
 237     }
 238
 239     return ret;
 240 }
 241
 242 static const AVFilterPad avfilter_af_resample_inputs[] = {
 243     {
 244         .name           = "default",
 245         .type           = AVMEDIA_TYPE_AUDIO,
 246         .filter_frame   = filter_frame,
 247         .min_perms      = AV_PERM_READ
 248     },
 249     { NULL }
 250 };
 251
 252 static const AVFilterPad avfilter_af_resample_outputs[] = {
 253     {
 254         .name          = "default",
 255         .type          = AVMEDIA_TYPE_AUDIO,
 256         .config_props  = config_output,
 257         .request_frame = request_frame
 258     },
 259     { NULL }
 260 };
 261
 262 AVFilter avfilter_af_resample = {
 263     .name          = "resample",
 264     .description   = NULL_IF_CONFIG_SMALL("Audio resampling and conversion."),
 265     .priv_size     = sizeof(ResampleContext),
 266
 267     .uninit         = uninit,
 268     .query_formats  = query_formats,
 269
 270     .inputs    = avfilter_af_resample_inputs,
 271     .outputs   = avfilter_af_resample_outputs,
 272 };