Electronic device for encoding or decoding frames of video and method for controlling thereof

1. A control method of an electronic device, the method comprising:

obtaining a video;

detecting a user gaze based on information on a direction on which the electronic device is tilted;

determining a part of a first frame of the video corresponding to the detected user gaze;

predicting a user gaze in at least one frame after the first frame;

determining, from the first frame, a part corresponding to the predicted user gaze in the at least one frame after the first frame;

determining a decoding-target part in the first frame, the decoding-target part including the part of the first frame corresponding to the detected user gaze, the part corresponding to the predicted user gaze in the at least one frame after the first frame, and an additional part including pixels of a predetermined number from a boundary of the part of the first frame corresponding to the detected user gaze and a boundary of the part corresponding to the predicted user gaze in the at least one frame after the first frame;

decoding the decoding-target part; and

displaying an image of the part of the first frame corresponding to the detected user gaze among the decoding-target part.

2. The method of claim 1 , wherein the predetermined number of pixels is variable based on a reliability of the predicted user gaze in the at least one frame after the first frame.

3. The method of claim 1 , further comprising:

determining a part corresponding to a user gaze in a second frame of the video;

decoding the part corresponding to the user gaze in the second frame; and

displaying an image associated with the part corresponding to the user gaze in the second frame.

4. The method of claim 3 , wherein decoding the part corresponding to the user gaze in the second frame comprises:

predicting at least one block of the part corresponding to the user gaze in the second frame from at least one block of the decoding-target part of the first frame.

5. The method of claim 3 , wherein decoding the part corresponding to the user gaze in the second frame comprises:

determining a decoding-target part of the second frame, which includes the part corresponding to the user gaze in the second frame and has a size greater than or equal to the part corresponding to the user gaze in the second frame; and

decoding the decoding-target part of the second frame.

6. The method of claim 5 , further comprising:

if it is determined that at least one block in the decoding-target part of the second frame is not decodable, performing error correction with respect to the at least one block which is not decodable.

7. The method of claim 1 , wherein predicting the user gaze in the at least one frame after the first frame comprises:

predicting the user gaze in the at least one frame after the first frame based on at least one of sensing data from a sensor of the electronic device, a behavioral habit of a user of the electronic device, and information associated with content of the video.

8. The method of claim 1 , wherein decoding the decoding-target part comprises:

decoding a first block of the decoding-target part independently; and

predicting a second block of the decoding-target part by referring to the first block,

wherein the first block is not included in the part corresponding to the detected user gaze in the first frame and the second block is included in the part corresponding to the detected user gaze in the first frame.

9. The method of claim 8 , further comprising:

if it is determined that at least one block in the decoding-target part of the first frame is not decodable, performing error correction with respect to the at least one block that is not decodable.

10. An electronic device, comprising:

a display; and

a processor configured to:

obtain a video;

detect a user gaze based on information on a direction on which the electronic device is tilted;

determine a part of a first frame of the video corresponding to the detected user gaze;

predict a user gaze in at least one frame after the first frame;

determine, from the first frame, a part corresponding to the predicted user gaze in the at least one frame after the first frame;

determine a decoding-target part in the first frame, the decoding-target part including the part of the first frame corresponding to the detected user gaze, the part corresponding to the predicted user gaze in the at least one frame after the first frame, and an additional part including a predetermined number of pixels from a boundary of the part of the first frame corresponding to the detected user gaze and a boundary of the part corresponding to the predicted user gaze in the at least one frame after the first frame;

decode the decoding-target part; and

display, on the display, an image associated with the part of the first frame corresponding to the detected user gaze among the decoding-target part.

11. The electronic device of claim 10 , wherein the processor is further configured to:

predict the user gaze in the at least one frame after the first frame based on at least one of sensing data from a sensor of the electronic device, a behavioral habit of a user of the electronic device, and information associated with content of the video.

12. The electronic device of claim 10 , wherein the processor is further configured to:

decode a first block of the decoding-target part independently; and

predict a second block of the decoding-target part by referring to the first block,

wherein the first block is not included in the part corresponding to the user gaze in the first frame and the second block is included in the part corresponding to the user gaze in the first frame.

13. A control method of an electronic device that performs encoding, the method comprising:

obtaining a video including a wide-angle image for providing a virtual reality service;

receiving information associated with a current user gaze from an electronic device that performs decoding;

determining a part of a first frame of the video corresponding to the current user gaze;

predicting a user gaze in at least one frame after the first frame;

determining, from the first frame, a part corresponding to the predicted user gaze in the at least one frame after the first frame;

determining an encoding-target part in the first frame, the encoding-target part including the part of the first frame corresponding to the current user gaze, the part corresponding to the predicted user gaze in the at least one frame after the first frame, and an additional part including a predetermined number of pixels from a boundary of the part of the first frame corresponding to the user gaze and the part corresponding to the predicted user gaze in the at least one frame after the first frame;

encoding the encoding-target part; and

transmitting encoded data to the electronic device that performs decoding.

14. The method of claim 13 , wherein determining the encoding-target part comprises:

determining the encoding-target part including the part corresponding to the user gaze in the first frame and a part corresponding to a user gaze in at least one frame after the first frame.

15. The method of claim 13 , wherein the encoding-target part includes a plurality of blocks, and the sizes of the plurality of blocks are identical to or different from one another.

16. The method of claim 13 , wherein determining the part corresponding to the user gaze in the first frame comprises:

determining the part corresponding to the user gaze in the first frame by considering a delay between a time when encoding is performed and a time when displaying is performed in the electronic device that performs decoding.