Video playback device and control method thereof

1. A device comprising:

a display;

a memory storing one or more instructions; and

at least one processor configured to display a first video on at least one portion of the display by executing the one or more instructions to:

compare an aspect ratio of the first video with an aspect ratio of a display area of the display;

determine a category of the first video based on at least one frame included in the first video, when the aspect ratio of the first video is different from the aspect ratio of the display area;

select a trained artificial intelligence (AI) model related to the category of the first video;

obtain an expanded video by applying the at least one frame of the first video to the trained AI model, the expanded video having an aspect ratio corresponding to the aspect ratio of the display area; and

display the expanded video in the display area.

2. The device of claim 1 , wherein the at least one processor is further configured to execute the one or more instructions to identify a letterbox to be displayed in the display area when the aspect ratio of the first video is different from the aspect ratio of the display area.

3. The device of claim 1 , wherein the at least one processor is further configured to execute the one or more instructions to:

extract frames included in the first video;

generate training data to be input to the trained AI model based on the extracted frames; and

obtain the expanded video by updating the trained AI model by inputting the training data to the trained AI model.

4. The device of claim 1 , wherein the at least one processor is further configured to execute the one or more instructions to generate a frame of the expanded video corresponding to a reference frame included in the first video by inputting the reference frame and a resized frame obtained by resizing the reference frame to the trained AI model.

5. The device of claim 4 , wherein the at least one processor is further configured to execute the one or more instructions to:

extract the reference frame, at least one previous frame, and at least one next frame included in the first video; and

apply the reference frame, the at least one previous frame, and the at least one next frame, to the trained AI model.

6. The device of claim 1 , wherein the device further comprises a communicate interface configured to transmit the first video to a server and receive, from the server, the trained AI model generated by the server using the first video, and

wherein the at least one processor is further configured to execute the one or more instructions to obtain the expanded video by inputting the at least one frame of the first video to the trained AI model received from the server.

7. The device of claim 4 , wherein the at least one processor is further configured to execute the one or more instructions to generate the frame of the expanded video corresponding to the reference frame included in the first video by training the trained AI model by inputting the reference frame, at least one previous frame, and at least one next frame, to the trained AI model.

8. The device of claim 4 , wherein the device further comprises a communicate interface, and

wherein the at least one processor is further configured to execute the one or more instructions to:

detect at least one of a pattern and a color constituting the reference frame included in the first video;

search for an image related to the detected at least one of the pattern and the color by using the communicate interface; and

generate the frame of the expanded video corresponding to the reference frame by inputting the reference frame and the searched image to the trained AI model.

9. The device of claim 1 , wherein the at least one processor is further configured to execute the one or more instructions to:

identify an object included in the at least one frame of the first video; and

determine the category of the first video according to the object.

10. The device of claim 1 , wherein the category comprises at least one from among a scientific fiction (SF) movie, a documentary, a live performance, a 2D animation, a 3D animation, an augmented reality (AR) video and a hologram video.

11. A method of displaying a video, the method comprising:

comparing an aspect ratio of a first video with an aspect ratio of a display area in which the first video is to be displayed;

determining a category of the first video based on at least one frame included in the first video, when the aspect ratio of the first video is different from the aspect ratio of the display area;

selecting a trained artificial intelligence (AI) model related to the category of the first video;

obtaining an expanded video by applying the at least one frame of the first video to the trained AI model, the expanded video having an aspect ratio corresponding to the aspect ratio of the display area; and

displaying the expanded video in the display area.

12. The method of claim 11 , wherein the comparing the aspect ratio of the first video with the aspect ratio of the display area comprises identifying a letterbox to be displayed in the display area when the aspect ratio of the first video is different from the aspect ratio of the display area.

13. The method of claim 11 , wherein the obtaining of the expanded video comprises:

extracting frames included in the first video;

generating training data to be input to the trained AI model based on the extracted frames; and

obtaining the expanded video by updating the trained AI model by inputting the training data to the trained AI model.

14. The method of claim 11 , wherein the obtaining the expanded video comprises generating a frame of the expanded video corresponding to a reference frame included in the first video by inputting the reference frame and a resized frame obtained by resizing the reference frame to the trained AI model.

15. The method of claim 14 , wherein the obtaining of the expanded video comprises:

extracting the reference frame, at least one previous frame, and at least one next frame included in the first video; and

applying the reference frame, the at least one previous frame, and the at least one next frame, to the trained AI model.

16. The method of claim 11 , wherein the obtaining of the expanded video comprises:

transmitting the first video to a server and receive, from the server, the trained AI model generated by the server using the first video; and

obtaining the expanded video by inputting the at least one frame of the first video to the trained AI model received from the server.

17. The method of claim 14 , wherein the obtaining of the expanded video comprises generating the frame of the expanded video corresponding to the reference frame included in the first video by training the trained AI model by inputting the reference frame, at least one previous frame, and at least one next frame, to the trained AI model.

18. The method of claim 14 , wherein the obtaining of the expanded video comprises:

detecting at least one of a pattern and a color constituting the reference frame included in the first video;

searching for an image related to the detected at least one of the pattern and the color by using a communicate interface; and

generating the frame of the expanded video corresponding to the reference frame by inputting the reference frame and the searched image to the trained AI model.

19. The method of claim 11 , wherein the determining the category of the first video further comprises identifying an object included in the at least one frame of the first video, and determining the category of the first video according to the object.

20. The method of claim 11 , wherein the category comprises at least one from among a scientific fiction (SF) movie, a documentary, a live performance, a 2D animation, a 3D animation, an augmented reality (AR) video and a hologram video.