title: Upload a video captions file to Facebook?
body: <p>According to Facebook's <a href="https://developers.facebook.com/docs/graph-api/reference/video/captions/" rel="nofollow">documentation</a> and this bug <a href="https://developers.facebook.com/bugs/1470577926590877" rel="nofollow">report</a> the contents of the .srt file should be in the captions_file parameter. I have tried doing this, but continue to get the error:</p>
  
  <pre><code>facebookSDK.GraphAPIError: (#100) Invalid file. Expected file of one of the following types: application/octet-stream
  </code></pre>
  
  <p>This is the same error Facebook user Ravi mentions in the bug report. What am I doing wrong? Do the file contents need to be converted to binary? Does a Content-Type:application/octet-stream header need to be added? What specifically needs to be sent via HTTP request?  </p>