title: Changing bitrate on the fly in AVCaptureSession
body: <p>I developed a fully functional live streaming app on iOS but my biggest issue right now is the Quality of Service. I implemented an RTSP protocol on the phone to send SR packets and handle RR packets for QoS informations. I need to find a way to change the bitrate settings for my stream session on the fly in order to get a smooth stream.</p>
  
  <p>Currently I can set my own custom settings with this method :</p>
  
  <pre><code>(AVAssetWriterInput *)assetWriterInputWithMediaType:(NSString *)mediaType outputSettings:(NSDictionary *)outputSettings
  </code></pre>
  
  <p>However, outputSettings is readonly so I need to find a way to deal with it.</p>
  
  <pre><code>@property(nonatomic, readonly) NSDictionary *outputSettings
  </code></pre>
  
  <p>I saw that LiVu app can do it, so there should be a way to do it too :)</p>
  
  <p>So is it possible to change the bitrate of an AVCaptureSession without restarting it and configuring a new AVCaptureInput? I saw we can change some defined presets but I want to configure the bitrate with more accuracy.</p>