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ffmpeg-4.2.2/libavdevice/utils.c 1.85 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "internal.h"
  #include "libavutil/opt.h"
  #include "libavformat/avformat.h"
  
  int ff_alloc_input_device_context(AVFormatContext **avctx, AVInputFormat *iformat, const char *format)
  {
      AVFormatContext *s;
      int ret = 0;
  
      *avctx = NULL;
      if (!iformat && !format)
          return AVERROR(EINVAL);
      if (!(s = avformat_alloc_context()))
          return AVERROR(ENOMEM);
  
      if (!iformat)
          iformat = av_find_input_format(format);
      if (!iformat || !iformat->priv_class || !AV_IS_INPUT_DEVICE(iformat->priv_class->category)) {
          ret = AVERROR(EINVAL);
          goto error;
      }
      s->iformat = iformat;
      if (s->iformat->priv_data_size > 0) {
          s->priv_data = av_mallocz(s->iformat->priv_data_size);
          if (!s->priv_data) {
              ret = AVERROR(ENOMEM);
              goto error;
          }
          if (s->iformat->priv_class) {
              *(const AVClass**)s->priv_data= s->iformat->priv_class;
              av_opt_set_defaults(s->priv_data);
          }
      } else
          s->priv_data = NULL;
  
      *avctx = s;
      return 0;
    error:
      avformat_free_context(s);
      return ret;
  }