libavfilter/buffersink.c

   1 /*
   2  * Copyright (c) 2011 Stefano Sabatini
   3  *
   4  * This file is part of Libav.
   5  *
   6  * Libav is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * Libav 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with Libav; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * buffer sink
  24  */
  25
  26 #include "libavutil/audio_fifo.h"
  27 #include "libavutil/avassert.h"
  28 #include "libavutil/channel_layout.h"
  29 #include "libavutil/common.h"
  30 #include "libavutil/mathematics.h"
  31
  32 #include "audio.h"
  33 #include "avfilter.h"
  34 #include "buffersink.h"
  35 #include "internal.h"
  36
  37 typedef struct {
  38     AVFilterBufferRef *cur_buf;  ///< last buffer delivered on the sink
  39     AVAudioFifo  *audio_fifo;    ///< FIFO for audio samples
  40     int64_t next_pts;            ///< interpolating audio pts
  41 } BufferSinkContext;
  42
  43 static av_cold void uninit(AVFilterContext *ctx)
  44 {
  45     BufferSinkContext *sink = ctx->priv;
  46
  47     if (sink->audio_fifo)
  48         av_audio_fifo_free(sink->audio_fifo);
  49 }
  50
  51 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *buf)
  52 {
  53     BufferSinkContext *s = link->dst->priv;
  54
  55     av_assert0(!s->cur_buf);
  56     s->cur_buf    = buf;
  57
  58     return 0;
  59 }
  60
  61 int av_buffersink_read(AVFilterContext *ctx, AVFilterBufferRef **buf)
  62 {
  63     BufferSinkContext *s    = ctx->priv;
  64     AVFilterLink      *link = ctx->inputs[0];
  65     int ret;
  66
  67     if (!buf)
  68         return ff_poll_frame(ctx->inputs[0]);
  69
  70     if ((ret = ff_request_frame(link)) < 0)
  71         return ret;
  72
  73     if (!s->cur_buf)
  74         return AVERROR(EINVAL);
  75
  76     *buf       = s->cur_buf;
  77     s->cur_buf = NULL;
  78
  79     return 0;
  80 }
  81
  82 static int read_from_fifo(AVFilterContext *ctx, AVFilterBufferRef **pbuf,
  83                           int nb_samples)
  84 {
  85     BufferSinkContext *s = ctx->priv;
  86     AVFilterLink   *link = ctx->inputs[0];
  87     AVFilterBufferRef *buf;
  88
  89     if (!(buf = ff_get_audio_buffer(link, AV_PERM_WRITE, nb_samples)))
  90         return AVERROR(ENOMEM);
  91     av_audio_fifo_read(s->audio_fifo, (void**)buf->extended_data, nb_samples);
  92
  93     buf->pts = s->next_pts;
  94     s->next_pts += av_rescale_q(nb_samples, (AVRational){1, link->sample_rate},
  95                                 link->time_base);
  96
  97     *pbuf = buf;
  98     return 0;
  99
 100 }
 101
 102 int av_buffersink_read_samples(AVFilterContext *ctx, AVFilterBufferRef **pbuf,
 103                                int nb_samples)
 104 {
 105     BufferSinkContext *s = ctx->priv;
 106     AVFilterLink   *link = ctx->inputs[0];
 107     int ret = 0;
 108
 109     if (!s->audio_fifo) {
 110         int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
 111         if (!(s->audio_fifo = av_audio_fifo_alloc(link->format, nb_channels, nb_samples)))
 112             return AVERROR(ENOMEM);
 113     }
 114
 115     while (ret >= 0) {
 116         AVFilterBufferRef *buf;
 117
 118         if (av_audio_fifo_size(s->audio_fifo) >= nb_samples)
 119             return read_from_fifo(ctx, pbuf, nb_samples);
 120
 121         ret = av_buffersink_read(ctx, &buf);
 122         if (ret == AVERROR_EOF && av_audio_fifo_size(s->audio_fifo))
 123             return read_from_fifo(ctx, pbuf, av_audio_fifo_size(s->audio_fifo));
 124         else if (ret < 0)
 125             return ret;
 126
 127         if (buf->pts != AV_NOPTS_VALUE) {
 128             s->next_pts = buf->pts -
 129                           av_rescale_q(av_audio_fifo_size(s->audio_fifo),
 130                                        (AVRational){ 1, link->sample_rate },
 131                                        link->time_base);
 132         }
 133
 134         ret = av_audio_fifo_write(s->audio_fifo, (void**)buf->extended_data,
 135                                   buf->audio->nb_samples);
 136         avfilter_unref_buffer(buf);
 137     }
 138
 139     return ret;
 140 }
 141
 142 static const AVFilterPad avfilter_vsink_buffer_inputs[] = {
 143     {
 144         .name        = "default",
 145         .type        = AVMEDIA_TYPE_VIDEO,
 146         .filter_frame = filter_frame,
 147         .min_perms   = AV_PERM_READ,
 148         .needs_fifo  = 1
 149     },
 150     { NULL }
 151 };
 152
 153 AVFilter avfilter_vsink_buffer = {
 154     .name      = "buffersink",
 155     .description = NULL_IF_CONFIG_SMALL("Buffer video frames, and make them available to the end of the filter graph."),
 156     .priv_size = sizeof(BufferSinkContext),
 157     .uninit    = uninit,
 158
 159     .inputs    = avfilter_vsink_buffer_inputs,
 160     .outputs   = NULL,
 161 };
 162
 163 static const AVFilterPad avfilter_asink_abuffer_inputs[] = {
 164     {
 165         .name           = "default",
 166         .type           = AVMEDIA_TYPE_AUDIO,
 167         .filter_frame   = filter_frame,
 168         .min_perms      = AV_PERM_READ,
 169         .needs_fifo     = 1
 170     },
 171     { NULL }
 172 };
 173
 174 AVFilter avfilter_asink_abuffer = {
 175     .name      = "abuffersink",
 176     .description = NULL_IF_CONFIG_SMALL("Buffer audio frames, and make them available to the end of the filter graph."),
 177     .priv_size = sizeof(BufferSinkContext),
 178     .uninit    = uninit,
 179
 180     .inputs    = avfilter_asink_abuffer_inputs,
 181     .outputs   = NULL,
 182 };