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• YouTube's HD Video Streaming Server Technology ?

  30 septembre 2013, par bgentry

  Lately I've been researching different methods for streaming MP4s to the browser. Flash Media Server is an obvious choice here (using Cloudfront), and most solutions I've seen use the RTMP protocol.

  However, I spent some time on YouTube with Firebug and Chrome debugger figuring out how their streaming worked and I discovered some interesting differences between some of their videos and quality rates.

  My two sample videos are A and B. A is available up to 480p and B is available up to 1080p. For both videos, all rates up to 480p are served in an FLV container with H.264 video and AAC audio, over HTTP. What's interesting here is that if you have not yet downloaded (cached) the entire video, and you try to skip forward to an uncached part of the video, a new request will be made with a 'begin' parameter equal to the target offset in milliseconds. Example from Video A at 480p :

  http://v11.lscache8.c.youtube.com/videoplayback?ip=0.0.0.0&sparams=id%2Cexpire%2Cip%2Cipbits%2Citag%2Calgorithm%2Cburst%2Cfactor%2Coc%3AU0dWTldQVF9FSkNNNl9PSlhJ&fexp=904806%2C902906%2C903711&algorithm=throttle-factor&itag=35&ipbits=0&burst=40&sver=3&expire=1279756800&key=yt1&signature=D2D704D63C242CF187CAA5B5D5BAFB8DFACAC5FF.39180C01559C976717B651A7EB1D0C6249231EB7&factor=1.25&id=8568eb3135971f6f&begin=111863
  
  
  
  Response Headers:
  
  Cache-Control:public,max-age=23472
  
  Connection:close
  
  Content-Length:14320637
  
  Content-Type:video/x-flv
  
  Date:Wed, 21 Jul 2010 17:23:48 GMT
  
  Expires:Wed, 21 Jul 2010 23:55:00 GMT
  
  Last-Modified:Wed, 19 May 2010 12:31:41 GMT
  
  Server:gvs 1.0
  
  X-Content-Type-Options:nosniff

  The file returned by this URL is a fully valid FLV containing only the portion of the video after the requested offset.

  I did the same kind of test on the higher resolution versions of Video B. At 720p and 1080p, YouTube will return a video in an MP4 container, also with H.264 video and AAC audio. What's impressive to me is that their server takes the same type of offset for an MP4 video (via the 'begin' parameter) and returns a valid, streamable MP4 (moov atom at the front of the file with correct offsets) that also only includes the requested portion of the video.

  So, how does YouTube do this ? How do they generate the FLV or MP4 container on the fly with the correct headers and only the desired segment of the requested video ? I know this can be accomplished using FFMPEG to seek to the desired start point and the qt-faststart script to reposition the moov atom to the front of the stream, but it seems like this would be too slow to handle on-demand for millions of YouTube viewers.

  Ideas ?

  Thanks in advance !

  Footnote : I am not allowed to include more than 1 link at this point, so here is Video A's URL : http:// www.youtube .com/watch ?v=hWjrMTWXH28 "Video available up to 480p"

• How to i add a background music to a video in React Native ?

  23 août 2023, par James

  How do I add background music to a video in React Native ? using ffmpeg-kit ? https://github.com/arthenica/ffmpeg-kit/tree/main/react-native

  


  I have a video in my project root folder, But the audio I want to add is a remote URL stored in the cloud music link is https://storage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4

  


  Can anyone give me a basic example to do this in React Native ?

  


• Android FFmpegMediaPlayer - MediaPlayer error(0, 0)

  14 décembre 2016, par Dionis Beqiraj

  I’m using this piece of code to play an acc that is on the cloud with FFmpegMediaPlayer taken from here :

  https://github.com/wseemann/FFmpegMediaPlayer

  Code :

  FFmpegMediaPlayer player = new FFmpegMediaPlayer();
  
  try {
  
    player.setAudioStreamType(AudioManager.STREAM_MUSIC);
  
    player.setDataSource(url);
  
    player.prepareAsync();
  
  } catch ( IOException | ExecutionException | InterruptedException e ){
  
        e.printStackTrace();
  
  }

  When the URL format is like "http://something.com/audio.aac" that code works fine.

  But, when the URL is like "https://something.com/audio.aac?something_else_here" that code doesn’t work and it fires en Error(0,0).

  Before FFmpegMediaPlayer I used the MediaPlayer with exact the same methods. Sometimes it had the same problems sometimes not, so I thought to switch to FFmpegMediaPlayer even because it is faster, but I’m not handling this error.

  Does anyone now how to deal with this ?