Method and apparatus for buffer management in cloud based virtual reality services

A buffer management method performed by a server to provide a cloud-based virtual reality service, comprising:

• receiving user's motion information from a user terminal via a network;
• calculating user's first viewpoint based on user's first motion information among the received user's motion information;
• calculating user's second viewpoint based on user's second motion information subsequent to the first motion information among the received user's motion information;
• determining a plurality of image tiles corresponding to a content to be displayed on the user terminal based on the first viewpoint;
• and
• transmitting modified image tiles obtained by modifying the plurality of image tiles to the user terminal via the network,
• wherein the modified image tiles are modified based on the second viewpoint according to a difference between the first viewpoint and the second viewpoint with a predetermined value, and
• wherein the modified image tiles are modified by deleting image tiles that is not consistent with the second viewpoint among the plurality of image tiles.

A server apparatus for providing a cloud-based virtual reality service, comprising:

• a transmission buffer;
• and
• one or plurality of microprocessors configured to:
• receive user's motion information from a user terminal via a network,
• calculate user's first viewpoint based on user's first motion information among the received user's motion information,
• calculate user's second viewpoint based on user's second motion information subsequent to the first motion information among the received user's motion information,
• determine a plurality of image tiles corresponding to a content to be displayed on the user terminal based on the first viewpoint,
• transmit modified image tiles obtained by modifying the plurality of image tiles to the user terminal via the network,
• wherein the modified image tiles are modified based on the second viewpoint according to a difference between the first viewpoint and the second viewpoint with a predetermined value, and
• wherein the modified image tiles are modified by deleting image tiles that is not consistent with the second viewpoint among the plurality of image tiles.