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

   1 /*
   2  * Copyright (c) 2007 Bobby Bingham
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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     inlink->cur_buf = NULL;
  95 }
  96
  97 static void queue_pop(FifoContext *s)
  98 {
  99     Buf *tmp = s->root.next->next;
 100     if (s->last == s->root.next)
 101         s->last = &s->root;
 102     av_freep(&s->root.next);
 103     s->root.next = tmp;
 104 }
 105
 106 static void end_frame(AVFilterLink *inlink) { }
 107
 108 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { }
 109
 110 /**
 111  * Move data pointers and pts offset samples forward.
 112  */
 113 static void buffer_offset(AVFilterLink *link, AVFilterBufferRef *buf,
 114                           int offset)
 115 {
 116     int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
 117     int planar = av_sample_fmt_is_planar(link->format);
 118     int planes = planar ? nb_channels : 1;
 119     int block_align = av_get_bytes_per_sample(link->format) * (planar ? 1 : nb_channels);
 120     int i;
 121
 122     av_assert0(buf->audio->nb_samples > offset);
 123
 124     for (i = 0; i < planes; i++)
 125         buf->extended_data[i] += block_align*offset;
 126     if (buf->data != buf->extended_data)
 127         memcpy(buf->data, buf->extended_data,
 128                FFMIN(planes, FF_ARRAY_ELEMS(buf->data)) * sizeof(*buf->data));
 129     buf->linesize[0] -= block_align*offset;
 130     buf->audio->nb_samples -= offset;
 131
 132     if (buf->pts != AV_NOPTS_VALUE) {
 133         buf->pts += av_rescale_q(offset, (AVRational){1, link->sample_rate},
 134                                  link->time_base);
 135     }
 136 }
 137
 138 static int calc_ptr_alignment(AVFilterBufferRef *buf)
 139 {
 140     int planes = av_sample_fmt_is_planar(buf->format) ?
 141                  av_get_channel_layout_nb_channels(buf->audio->channel_layout) : 1;
 142     int min_align = 128;
 143     int p;
 144
 145     for (p = 0; p < planes; p++) {
 146         int cur_align = 128;
 147         while ((intptr_t)buf->extended_data[p] % cur_align)
 148             cur_align >>= 1;
 149         if (cur_align < min_align)
 150             min_align = cur_align;
 151     }
 152     return min_align;
 153 }
 154
 155 static int return_audio_frame(AVFilterContext *ctx)
 156 {
 157     AVFilterLink *link = ctx->outputs[0];
 158     FifoContext *s = ctx->priv;
 159     AVFilterBufferRef *head = s->root.next->buf;
 160     AVFilterBufferRef *buf_out;
 161     int ret;
 162
 163     if (!s->buf_out &&
 164         head->audio->nb_samples >= link->request_samples &&
 165         calc_ptr_alignment(head) >= 32) {
 166         if (head->audio->nb_samples == link->request_samples) {
 167             buf_out = head;
 168             queue_pop(s);
 169         } else {
 170             buf_out = avfilter_ref_buffer(head, AV_PERM_READ);
 171             buf_out->audio->nb_samples = link->request_samples;
 172             buffer_offset(link, head, link->request_samples);
 173         }
 174     } else {
 175         int nb_channels = av_get_channel_layout_nb_channels(link->channel_layout);
 176
 177         if (!s->buf_out) {
 178             s->buf_out = ff_get_audio_buffer(link, AV_PERM_WRITE,
 179                                              link->request_samples);
 180             if (!s->buf_out)
 181                 return AVERROR(ENOMEM);
 182
 183             s->buf_out->audio->nb_samples = 0;
 184             s->buf_out->pts               = head->pts;
 185             s->allocated_samples          = link->request_samples;
 186         } else if (link->request_samples != s->allocated_samples) {
 187             av_log(ctx, AV_LOG_ERROR, "request_samples changed before the "
 188                    "buffer was returned.\n");
 189             return AVERROR(EINVAL);
 190         }
 191
 192         while (s->buf_out->audio->nb_samples < s->allocated_samples) {
 193             int len = FFMIN(s->allocated_samples - s->buf_out->audio->nb_samples,
 194                             head->audio->nb_samples);
 195
 196             av_samples_copy(s->buf_out->extended_data, head->extended_data,
 197                             s->buf_out->audio->nb_samples, 0, len, nb_channels,
 198                             link->format);
 199             s->buf_out->audio->nb_samples += len;
 200
 201             if (len == head->audio->nb_samples) {
 202                 avfilter_unref_buffer(head);
 203                 queue_pop(s);
 204
 205                 if (!s->root.next &&
 206                     (ret = ff_request_frame(ctx->inputs[0])) < 0) {
 207                     if (ret == AVERROR_EOF) {
 208                         av_samples_set_silence(s->buf_out->extended_data,
 209                                                s->buf_out->audio->nb_samples,
 210                                                s->allocated_samples -
 211                                                s->buf_out->audio->nb_samples,
 212                                                nb_channels, link->format);
 213                         s->buf_out->audio->nb_samples = s->allocated_samples;
 214                         break;
 215                     }
 216                     return ret;
 217                 }
 218                 head = s->root.next->buf;
 219             } else {
 220                 buffer_offset(link, head, len);
 221             }
 222         }
 223         buf_out = s->buf_out;
 224         s->buf_out = NULL;
 225     }
 226     return ff_filter_samples(link, buf_out);
 227 }
 228
 229 static int request_frame(AVFilterLink *outlink)
 230 {
 231     FifoContext *fifo = outlink->src->priv;
 232     int ret = 0;
 233
 234     if (!fifo->root.next) {
 235         if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0)
 236             return ret;
 237     }
 238
 239     /* by doing this, we give ownership of the reference to the next filter,
 240      * so we don't have to worry about dereferencing it ourselves. */
 241     switch (outlink->type) {
 242     case AVMEDIA_TYPE_VIDEO:
 243         ff_start_frame(outlink, fifo->root.next->buf);
 244         ff_draw_slice (outlink, 0, outlink->h, 1);
 245         ff_end_frame  (outlink);
 246         queue_pop(fifo);
 247         break;
 248     case AVMEDIA_TYPE_AUDIO:
 249         if (outlink->request_samples) {
 250             return return_audio_frame(outlink->src);
 251         } else {
 252             ret = ff_filter_samples(outlink, fifo->root.next->buf);
 253             queue_pop(fifo);
 254         }
 255         break;
 256     default:
 257         return AVERROR(EINVAL);
 258     }
 259
 260     return ret;
 261 }
 262
 263 AVFilter avfilter_vf_fifo = {
 264     .name      = "fifo",
 265     .description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),
 266
 267     .init      = init,
 268     .uninit    = uninit,
 269
 270     .priv_size = sizeof(FifoContext),
 271
 272     .inputs    = (const AVFilterPad[]) {{ .name      = "default",
 273                                     .type            = AVMEDIA_TYPE_VIDEO,
 274                                     .get_video_buffer= ff_null_get_video_buffer,
 275                                     .start_frame     = start_frame,
 276                                     .draw_slice      = draw_slice,
 277                                     .end_frame       = end_frame,
 278                                     .rej_perms       = AV_PERM_REUSE2, },
 279                                   { .name = NULL}},
 280     .outputs   = (const AVFilterPad[]) {{ .name      = "default",
 281                                     .type            = AVMEDIA_TYPE_VIDEO,
 282                                     .request_frame   = request_frame, },
 283                                   { .name = NULL}},
 284 };
 285
 286 AVFilter avfilter_af_afifo = {
 287     .name        = "afifo",
 288     .description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),
 289
 290     .init      = init,
 291     .uninit    = uninit,
 292
 293     .priv_size = sizeof(FifoContext),
 294
 295     .inputs    = (AVFilterPad[]) {{ .name             = "default",
 296                                     .type             = AVMEDIA_TYPE_AUDIO,
 297                                     .get_audio_buffer = ff_null_get_audio_buffer,
 298                                     .filter_samples   = add_to_queue,
 299                                     .rej_perms        = AV_PERM_REUSE2, },
 300                                   { .name = NULL}},
 301     .outputs   = (AVFilterPad[]) {{ .name             = "default",
 302                                     .type             = AVMEDIA_TYPE_AUDIO,
 303                                     .request_frame    = request_frame, },
 304                                   { .name = NULL}},
 305 };