Does youtube store different video files for different bit rate?
Does youtube store different video files for different bit rate?



Yes



  is the technique called "resampling" ?



No



  Does youtube make live resampling for every user ?



No



  All this things happens live ?



No, not on youtube. But Yes on twitch.tv



  Or it encode and save different video files for different bitrate, so
  that when a user changes bitrate it servers that file.



Yes



  Isn't that a disk space destroyer too ?



Yes