title: Creating a AVAsset with a HTTP NSURL
body: <p>I'm trying to merge two <code>NSURLs</code> that contain video references. One of the urls point to a video on AWS and the other points to a video that is stored locally. My exporting code works because I've tried it with two local videos, but whenever I try merge the HTTP url and the local url I get this error: <code>Error Domain=NSURLErrorDomain Code=-1100 "The requested URL was not found on this server." UserInfo=0x155d2f20 {NSUnderlyingError=0x155b4f60 "The operation couldn’t be completed. No such file or directory", NSLocalizedDescription=The requested URL was not found on this server.}</code>
  This is the code to create the AVAssets:</p>
  
  <pre><code>AVAsset *firstAsset = [AVAsset assetWithURL:awsURL];
  </code></pre>
  
  <p>Does <code>AVAssetExportSession</code> require local urls to be used?</p>