title: ffmpeg, 'protocol not found' error
body: <p>i'm using next code:</p>
  
  <pre><code>const char *sFileOutput;
  AVOutputFormat *ofmt;
  AVFormatContext *ofcx;
  
          int main( int argc, char* argv[] )
          {
              av_log_set_level( AV_LOG_DEBUG );
              av_register_all();
              avcodec_register_all();
              avformat_network_init();
  
              char s1[40]={0};
              const time_t timer = time(NULL);
              u = localtime(&amp;timer);
              strftime(s1, 40, "%d.%m.%Y-%H:%M:%S.avi", u);
              sFileOutput=&amp;s1;
  
              //char *sFileOutput = "01.01.2017-23.23.23.avi";
  
              ofmt = av_guess_format( NULL, sFileOutput, NULL );
              ofcx = avformat_alloc_context();
              ofcx-&gt;oformat = ofmt;
              int ret2=avio_open( &amp;ofcx-&gt;pb, sFileOutput, AVIO_FLAG_WRITE);
              if(ret2&lt;0){
                  fprintf(stderr, "\nError occurred when opening output file: %s\n",av_err2str(ret2));
              }
          }
  </code></pre>
  
  <p>When i run it, i have error in console:</p>
  
  <pre><code>Error occurred when opening output file: Protocol not found
  </code></pre>
  
  <p>but if i uncomment string</p>
  
  <pre><code>char *sFileOutput = "01.01.2017-23.23.23.avi";
  </code></pre>
  
  <p>evirything is ok, progam is working without errors. please tell me what is wrong.</p>