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