libavfilter/vsrc_nullsrc.c

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 /**
  20  * @file libavfilter/vsrc_nullsrc.c
  21  * null video source
  22  */
  23
  24 #include "avfilter.h"
  25
  26 typedef struct {
  27     int w, h;
  28 } NullContext;
  29
  30 static int init(AVFilterContext *ctx, const char *args, void *opaque)
  31 {
  32     NullContext *priv = ctx->priv;
  33
  34     priv->w = 352;
  35     priv->h = 288;
  36
  37     if (args)
  38         sscanf(args, "%d:%d", &priv->w, &priv->h);
  39
  40     if (priv->w <= 0 || priv->h <= 0) {
  41         av_log(ctx, AV_LOG_ERROR, "Non-positive size values are not acceptable.\n");
  42         return -1;
  43     }
  44
  45     return 0;
  46 }
  47
  48 static int config_props(AVFilterLink *outlink)
  49 {
  50     NullContext *priv = outlink->src->priv;
  51
  52     outlink->w = priv->w;
  53     outlink->h = priv->h;
  54
  55     av_log(outlink->src, AV_LOG_INFO, "w:%d h:%d\n", priv->w, priv->h);
  56
  57     return 0;
  58 }
  59
  60 static int request_frame(AVFilterLink *link)
  61 {
  62     return -1;
  63 }
  64
  65 AVFilter avfilter_vsrc_nullsrc = {
  66     .name        = "nullsrc",
  67     .description = "Null video source, never return images.",
  68
  69     .init       = init,
  70     .priv_size = sizeof(NullContext),
  71
  72     .inputs    = (AVFilterPad[]) {{ .name = NULL}},
  73
  74     .outputs   = (AVFilterPad[]) {
  75         {
  76             .name            = "default",
  77             .type            = CODEC_TYPE_VIDEO,
  78             .config_props    = config_props,
  79             .request_frame   = request_frame,
  80         },
  81         { .name = NULL}
  82     },
  83 };