git.sesse.net Git - ffmpeg/blob - libavfilter/fifo.c

   1 /*
   2  * Copyright (c) 2007 Bobby Bingham
   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  * FIFO buffering filter
  24  */
  25
  26 #include "libavutil/avassert.h"
  27 #include "libavutil/audioconvert.h"
  28 #include "libavutil/mathematics.h"
  29 #include "libavutil/samplefmt.h"
  30
  31 #include "audio.h"
  32 #include "avfilter.h"
  33 #include "internal.h"
  34 #include "video.h"
  35
  36 typedef struct Buf {
  37     AVFilterBufferRef *buf;
  38     struct Buf        *next;
  39 } Buf;
  40
  41 typedef struct {
  42     Buf  root;
  43     Buf *last;   ///< last buffered frame
  44
  45     /**
  46      * When a specific number of output samples is requested, the partial
  47      * buffer is stored here
  48      */
  49     AVFilterBufferRef *buf_out;
  50     int allocated_samples;      ///< number of samples buf_out was allocated for
  51 } FifoContext;
  52
  53 static av_cold int init(AVFilterContext *ctx, const char *args)
  54 {
  55     FifoContext *fifo = ctx->priv;
  56     fifo->last = &fifo->root;
  57
  58     return 0;
  59 }
  60
  61 static av_cold void uninit(AVFilterContext *ctx)
  62 {
  63     FifoContext *fifo = ctx->priv;
  64     Buf *buf, *tmp;
  65
  66     for (buf = fifo->root.next; buf; buf = tmp) {
  67         tmp = buf->next;
  68         avfilter_unref_buffer(buf->buf);
  69         av_free(buf);
  70     }
  71
  72     avfilter_unref_buffer(fifo->buf_out);
  73 }
  74
  75 static int add_to_queue(AVFilterLink *inlink, AVFilterBufferRef *buf)
  76 {
  77     FifoContext *fifo = inlink->dst->priv;
  78
  79     fifo->last->next = av_mallocz(sizeof(Buf));
  80     if (!fifo->last->next) {
  81         avfilter_unref_buffer(buf);
  82         return AVERROR(ENOMEM);
  83     }
  84
  85     fifo->last = fifo->last->next;
  86     fifo->last->buf = buf;
  87
  88     return 0;
  89 }
  90
  91 static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)
  92 {
  93     add_to_queue(inlink, buf);
  94 }
  95
  96 static void queue_pop(FifoContext *s)
  97 {
  98     Buf *tmp = s->root.next->next;
  99     if (s->last == s->root.next)
 100         s->last = &s->root;
 101     av_freep(&s->root.next);
 102     s->root.next = tmp;
 103 }
 104
 105 static void end_frame(AVFilterLink *inlink) { }
 106
 107 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { }
 108
 109 /**
 110  * Move data pointers and pts offset samples forward.
 111  */
 112 static void buffer_offset(AVFilterLink *link, AVFilterBufferRef *buf,
 113                           int offset)
 114 {
 115     int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
 116     int planar = av_sample_fmt_is_planar(link->format);
 117     int planes = planar ? nb_channels : 1;
 118     int block_align = av_get_bytes_per_sample(link->format) * (planar ? 1 : nb_channels);
 119     int i;
 120
 121     av_assert0(buf->audio->nb_samples > offset);
 122
 123     for (i = 0; i < planes; i++)
 124         buf->extended_data[i] += block_align*offset;
 125     if (buf->data != buf->extended_data)
 126         memcpy(buf->data, buf->extended_data,
 127                FFMIN(planes, FF_ARRAY_ELEMS(buf->data)) * sizeof(*buf->data));
 128     buf->linesize[0] -= block_align*offset;
 129     buf->audio->nb_samples -= offset;
 130
 131     if (buf->pts != AV_NOPTS_VALUE) {
 132         buf->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
 133                                  link->time_base);
 134     }
 135 }
 136
 137 static int calc_ptr_alignment(AVFilterBufferRef *buf)
 138 {
 139     int planes = av_sample_fmt_is_planar(buf->format) ?
 140                  av_get_channel_layout_nb_channels(buf->audio->channel_layout) : 1;
 141     int min_align = 128;
 142     int p;
 143
 144     for (p = 0; p < planes; p++) {
 145         int cur_align = 128;
 146         while ((intptr_t)buf->extended_data[p] % cur_align)
 147             cur_align >>= 1;
 148         if (cur_align < min_align)
 149             min_align = cur_align;
 150     }
 151     return min_align;
 152 }
 153
 154 static int return_audio_frame(AVFilterContext *ctx)
 155 {
 156     AVFilterLink *link = ctx->outputs[0];
 157     FifoContext *s = ctx->priv;
 158     AVFilterBufferRef *head = s->root.next->buf;
 159     AVFilterBufferRef *buf_out;
 160     int ret;
 161
 162     if (!s->buf_out &&
 163         head->audio->nb_samples >= link->request_samples &&
 164         calc_ptr_alignment(head) >= 32) {
 165         if (head->audio->nb_samples == link->request_samples) {
 166             buf_out = head;
 167             queue_pop(s);
 168         } else {
 169             buf_out = avfilter_ref_buffer(head, AV_PERM_READ);
 170             buf_out->audio->nb_samples = link->request_samples;
 171             buffer_offset(link, head, link->request_samples);
 172         }
 173     } else {
 174         int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
 175
 176         if (!s->buf_out) {
 177             s->buf_out = ff_get_audio_buffer(link, AV_PERM_WRITE,
 178                                              link->request_samples);
 179             if (!s->buf_out)
 180                 return AVERROR(ENOMEM);
 181
 182             s->buf_out->audio->nb_samples = 0;
 183             s->buf_out->pts               = head->pts;
 184             s->allocated_samples          = link->request_samples;
 185         } else if (link->request_samples != s->allocated_samples) {
 186             av_log(ctx, AV_LOG_ERROR, "request_samples changed before the "
 187                    "buffer was returned.\n");
 188             return AVERROR(EINVAL);
 189         }
 190
 191         while (s->buf_out->audio->nb_samples < s->allocated_samples) {
 192             int len = FFMIN(s->allocated_samples - s->buf_out->audio->nb_samples,
 193                             head->audio->nb_samples);
 194
 195             av_samples_copy(s->buf_out->extended_data, head->extended_data,
 196                             s->buf_out->audio->nb_samples, 0, len, nb_channels,
 197                             link->format);
 198             s->buf_out->audio->nb_samples += len;
 199
 200             if (len == head->audio->nb_samples) {
 201                 avfilter_unref_buffer(head);
 202                 queue_pop(s);
 203
 204                 if (!s->root.next &&
 205                     (ret = ff_request_frame(ctx->inputs[0])) < 0) {
 206                     if (ret == AVERROR_EOF) {
 207                         av_samples_set_silence(s->buf_out->extended_data,
 208                                                s->buf_out->audio->nb_samples,
 209                                                s->allocated_samples -
 210                                                s->buf_out->audio->nb_samples,
 211                                                nb_channels, link->format);
 212                         s->buf_out->audio->nb_samples = s->allocated_samples;
 213                         break;
 214                     }
 215                     return ret;
 216                 }
 217                 head = s->root.next->buf;
 218             } else {
 219                 buffer_offset(link, head, len);
 220             }
 221         }
 222         buf_out = s->buf_out;
 223         s->buf_out = NULL;
 224     }
 225     return ff_filter_samples(link, buf_out);
 226 }
 227
 228 static int request_frame(AVFilterLink *outlink)
 229 {
 230     FifoContext *fifo = outlink->src->priv;
 231     int ret = 0;
 232
 233     if (!fifo->root.next) {
 234         if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0)
 235             return ret;
 236     }
 237
 238     /* by doing this, we give ownership of the reference to the next filter,
 239      * so we don't have to worry about dereferencing it ourselves. */
 240     switch (outlink->type) {
 241     case AVMEDIA_TYPE_VIDEO:
 242         ff_start_frame(outlink, fifo->root.next->buf);
 243         ff_draw_slice (outlink, 0, outlink->h, 1);
 244         ff_end_frame  (outlink);
 245         queue_pop(fifo);
 246         break;
 247     case AVMEDIA_TYPE_AUDIO:
 248         if (outlink->request_samples) {
 249             return return_audio_frame(outlink->src);
 250         } else {
 251             ret = ff_filter_samples(outlink, fifo->root.next->buf);
 252             queue_pop(fifo);
 253         }
 254         break;
 255     default:
 256         return AVERROR(EINVAL);
 257     }
 258
 259     return ret;
 260 }
 261
 262 AVFilter avfilter_vf_fifo = {
 263     .name      = "fifo",
 264     .description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),
 265
 266     .init      = init,
 267     .uninit    = uninit,
 268
 269     .priv_size = sizeof(FifoContext),
 270
 271     .inputs    = (AVFilterPad[]) {{ .name            = "default",
 272                                     .type            = AVMEDIA_TYPE_VIDEO,
 273                                     .get_video_buffer= ff_null_get_video_buffer,
 274                                     .start_frame     = start_frame,
 275                                     .draw_slice      = draw_slice,
 276                                     .end_frame       = end_frame,
 277                                     .rej_perms       = AV_PERM_REUSE2, },
 278                                   { .name = NULL}},
 279     .outputs   = (AVFilterPad[]) {{ .name            = "default",
 280                                     .type            = AVMEDIA_TYPE_VIDEO,
 281                                     .request_frame   = request_frame, },
 282                                   { .name = NULL}},
 283 };
 284
 285 AVFilter avfilter_af_afifo = {
 286     .name        = "afifo",
 287     .description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),
 288
 289     .init      = init,
 290     .uninit    = uninit,
 291
 292     .priv_size = sizeof(FifoContext),
 293
 294     .inputs    = (AVFilterPad[]) {{ .name             = "default",
 295                                     .type             = AVMEDIA_TYPE_AUDIO,
 296                                     .get_audio_buffer = ff_null_get_audio_buffer,
 297                                     .filter_samples   = add_to_queue,
 298                                     .rej_perms        = AV_PERM_REUSE2, },
 299                                   { .name = NULL}},
 300     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 301                                     .type             = AVMEDIA_TYPE_AUDIO,
 302                                     .request_frame    = request_frame, },
 303                                   { .name = NULL}},
 304 };