title: WEBRTC How to capture video from camera library?
body: <p>Can't load video from a UIImagePickerController using WebRTC. 
  With saved in-app Bundle file, it works, but if I use UIImagePickerController</p>
  
  <pre><code>UIImagePickerControllerDelegate.imagePickerController(_:didFinishPickingMediaWithInfo:))
  </code></pre>
  
  <p>so I use mediaInfo like this:</p>
  
  <pre><code>(info[.mediaURL] as! URL).path
  </code></pre>
  
  <p>This code I use to start capturing a video file </p>
  
  <pre><code>   public func startCaptureLocalVideoFile(name: String, renderer: RTCVideoRenderer) {
          print("startCaptureLocalVideoFile")
  
          stopLocalCapture()
  
          localRenderer = renderer
          videoCapturer = RTCFileVideoCapturer(delegate: videoSource)
  
          guard let capturer = videoCapturer as? RTCFileVideoCapturer else {
              print("WebRTCService can't get capturer")
              return
          }
  
          capturer.startCapturing(fromFileNamed: name) { error in
              print("startCapturing error ", error)
              return
          }
  
          localVideoTrack?.add(renderer)
      }
  </code></pre>
  
  <p>so I get this media info:</p>
  
  <pre><code>info  [__C.UIImagePickerControllerInfoKey(_rawValue: UIImagePickerControllerMediaURL): file:///private/var/mobile/Containers/Data/PluginKitPlugin/5F7A4469-5006-4590-8F59-396CD86A083B/tmp/trim.B46C5878-BAF2-432B-B627-9787D74CE7B0.MOV, __C.UIImagePickerControllerInfoKey(_rawValue: UIImagePickerControllerMediaType): public.movie, __C.UIImagePickerControllerInfoKey(_rawValue: UIImagePickerControllerReferenceURL): assets-library://asset/asset.MOV?id=33EECFB7-514A-435A-AA19-26A055FB9F06&amp;ext=MOV]
  </code></pre>
  
  <p>and this error:</p>
  
  <pre><code>startCapturing error  Error Domain=org.webrtc.RTCFileVideoCapturer Code=2001 "(null)" UserInfo={NSUnderlyingError=File /private/var/mobile/Containers/Data/PluginKitPlugin/5F7A4469-5006-4590-8F59-396CD86A083B/tmp/trim.B46C5878-BAF2-432B-B627-9787D74CE7B0.MOV not found in bundle}
  </code></pre>
  
  <p>Seems like it works with <code>Bundle.main</code> only, but we can't write to it.</p>
  
  <p>Am I doing it right? Maybe there is another way to accomplish this? 
  Thanks for the help!</p>