title: error LNK1120: unresolved externals
body: <p>I am trying to build the following code. But it gives the error as "error LNK1120: 5 unresolved externals". I'm using C++ in Visual Studio 2013. Libraries are included properly. Error comes at avformat_open_input method. I'm using muxing in ffmpeg in my code. Please help.</p>
  
  <pre><code>const char *url = "H:/Sanduni_projects/ad_2.mp4";
  
  AVFormatContext *s = NULL;
  int ret = avformat_open_input(&amp;s, url, NULL, NULL);
  if (ret &lt; 0)
      abort();
  
  AVDictionary *options = NULL;
  
  av_dict_set(&amp;options, "video_size", "640x480", 0);
  av_dict_set(&amp;options, "pixel_format", "rgb24", 0);
  
  if (avformat_open_input(&amp;s, url, NULL, &amp;options) &lt; 0){
      abort();
  }
  
  av_dict_free(&amp;options);
  
  AVDictionaryEntry *e;
  
  if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
      fprintf(stderr, "Option %s not recognized by the demuxer.\n", e-&gt;key);
      abort();
  }
  
  avformat_close_input(&amp;s);
  </code></pre>