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• Ideas for new HTML5 apps

  10 mars 2011, par silvia

  At the recent Linux conference in Brisbane, Australia, I promised a free copy of my book to the person that could send me the best idea for an HTML5 video application. I later also tweeted about it. While I didn’t get many emails, I am still impressed by the things people want to do. Amongst (...)

• Video Conferencing in HTML5 : WebRTC via Socket.io

  
  5 février 2013, par silvia

  Six months ago I experimented with Web sockets for WebRTC and the early implementations of PeerConnection in Chrome. Last week I gave a presentation about WebRTC at Linux.conf.au, so it was time to update that codebase.

  I decided to use socket.io for the signalling following the idea of Luc, which made the server code even smaller and reduced it to a mere reflector :

   var app = require(’http’).createServer().listen(1337) ;
   var io = require(’socket.io’).listen(app) ;
   io.sockets.on(’connection’, function(socket) 
  
           socket.on(’message’, function(message) 
  
           socket.broadcast.emit(’message’, message) ;
  
       ) ;
  
   ) ;
  

  Then I turned to the client code. I was surprised to see the massive changes that PeerConnection has gone through. Check out my slide deck to see the different components that are now necessary to create a PeerConnection.

  I was particularly surprised to see the SDP object now fully exposed to JavaScript and thus the ability to manipulate it directly rather than through some API. This allows Web developers to manipulate the type of session that they are asking the browsers to set up. I can imaging e.g. if they have support for a video codec in JavaScript that the browser does not provide built-in, they can add that codec to the set of choices to be offered to the peer. While it is flexible, I am concerned if this might create more problems than it solves. I guess we’ll have to wait and see.

  I was also surprised by the need to use ICE, even though in my experiment I got away with an empty list of ICE servers – the ICE messages just got exchanged through the socket.io server. I am not sure whether this is a bug, but I was very happy about it because it meant I could run the whole demo on a completely separate network from the Internet.

  The most exciting news since my talk is that Mozilla and Google have managed to get a PeerConnection working between Firefox and Chrome – this is the first cross-browser video conference call without a plugin ! The code differences are minor.

  Since the specification of the WebRTC API and of the MediaStream API are now official Working Drafts at the W3C, I expect other browsers will follow. I am also looking forward to the possibilities of :

  • multi-peer video conferencing like the efforts around webrtc.io,
  • the media stream recording API,
  • and the peer-to-peer data API.

  The best places to learn about the latest possibilities of WebRTC are webrtc.org and the W3C WebRTC WG. code.google.com has open source code that continues to be updated to the latest released and interoperable features in browsers.

  The video of my talk is in the process of being published. There is a MP4 version on the Linux Australia mirror server, but I expect it will be published properly soon. I will update the blog post when that happens.

• How to run FFMPEG at my web host server

  26 avril 2013, par user1978421

  I want to perform some video process at my web host server. I don't think the web host server will allow me to execute an exe file for security reasons.

  Should I use SharpFFMpeg ?

  I have downloaded SharpFFMpeg. But it's lacking a proper documentation.

  Can someone give one example how to perform a conversion from one video format to another ?

  I have written my execution program, but the compiler says it cannot file the file specified. What's wrong with it ?

          string command = @"D:\Recorded TV\ffmpeg.exe -i ""Australia's Toughest Police_QUEST_2013_04_17_21_57_00.wtv"" -s 800x400 throughCS.mp4";
  
          try
  
          {
  
              ProcessStartInfo psi = new ProcessStartInfo("\"" + command + "\"");
  
              psi.RedirectStandardOutput = true;
  
              psi.UseShellExecute = false;
  
              psi.CreateNoWindow = true;
  
              Process proc = new Process();
  
              proc.StartInfo = psi;
  
              proc.Start();
  
              string result = proc.StandardOutput.ReadToEnd();
  
              tb1.Text = result;
  
              Debug.WriteLine(result);
  
          }