Method of reproducing from storage medium storing interactive graphics stream activated in response to user's command

1. A method of reproducing an interactive graphics stream read from a storage medium by a reproducing apparatus, the method comprising:

reading an interactive graphics stream from the storage medium;

decoding the read interactive graphics stream;

determining a type of the read interactive graphics stream as a normal interactive graphics stream which is displayed at a designated time or an on-demand interactive graphics stream which is displayed when an activation command is received; and

blending the decoded interactive graphics stream with video data; and

when the decoded interactive graphics stream is the normal interactive graphics stream, outputting, to a display, the decoded interactive graphics stream at the designated and

when the decoded interactive graphics stream is the on-demand interactive graphics stream, outputting, to a display,the decoded interactive graphics stream when the activation command is received,

wherein the activation command corresponding to the on-demand interactive graphics stream is ignored if the activation command is generated after a predetermined time.

2. The method of claim 1 , wherein the normal interactive graphics stream and the on-demand interactive graphics stream have the same structure.

3. The method of claim 1 , wherein the determining includes analyzing a structure of the interactive graphics stream.

4. The method of claim 3 , wherein a structure of the normal interactive graphics stream is different from a structure of the on-demand interactive graphics stream.

5. The method of claim 1 , further comprising:

removing the blended data corresponding to the normal interactive graphics stream from the display at an output finish time that is configured to occur after the outputting of the blended data corresponding to the normal interactive graphics stream.

6. The method of claim 5 , wherein a composition_time out_pts field value recorded in an interactive composition segment of the normal interactive graphics stream indicates the output finish time.

7. The method of claim 1 , wherein the determining comprises: determining, from a field of the read interactive graphics stream, the type of the read interactive graphics stream.

8. The method of claim 1 , wherein the normal interactive graphics stream and the on-demand interactive graphics stream are contemporaneously streamed.

9. A method of reproducing an interactive graphics stream read from a storage medium by a reproducing apparatus, the method comprising:

reading an interactive graphics stream from the storage medium;

decoding the read interactive graphics stream;

determining a type of the read interactive graphics stream; and

blending the decoded interactive graphics stream with video data; and

one of outputting, to a display, the decoded interactive graphics stream at a designated time when the decoded interactive graphics stream is a normal interactive graphics stream and outputting, to a display, the decoded interactive graphics stream when an activation command is received when the decoded interactive graphics stream is an on-demand interactive graphics stream;

wherein, when the decoded interactive graphics stream is the on-demand interactive graphics stream, the blending includes:

reading a disp_flag flag indicating whether the on-demand interactive graphics stream is to be displayed from a player status register;

outputting, to a display, when a value of the disp_flag flag is a first value, an initial menu page indicating that the on-demand interactive graphics stream is ready to be activated;

outputting, to a display, a menu page according to a user command, when the activation command is received during display of the initial menu page; and

ignoring the activation command when the value of the disp_flag flag is a second value different from the first value.

10. The method of claim 9 , wherein, when the activation command is received from a user interface of a remote control, the initial menu page is displayed.

11. A method of reproducing an interactive graphics stream read from a storage medium by a reproducing apparatus, the method comprising:

reading an interactive graphics stream from the storage medium;

decoding the read interactive graphics stream;

determining a type of the read interactive graphics stream; and

blending the decoded interactive graphics stream with video data; and

one of outputting, to a display, the decoded interactive graphics stream at a designated time when the decoded interactive graphics stream is a normal interactive graphics stream and outputting, to a display, the decoded interactive graphics stream when an activation command is received when the decoded interactive graphics stream is an on-demand interactive graphics stream;

wherein the determining of the type of the read interactive graphics stream includes analyzing a segment_type field of an interactive composition segment (ICS).

12. The method of claim 11 , wherein the segment type field indicates a segment type and is located in a segment_descriptor field.

13. The method of claim 12 , wherein the segment_type field is defined such that the normal interactive graphics stream type has a value 0x18 and the on-demand interactive graphics stream type has a value 0x19.

14. A method of reproducing an interactive graphics stream read from a storage medium by a reproducing apparatus, the method comprising:

reading an interactive graphics stream from the storage medium;

decoding the read interactive graphics stream;

determining a type of the read interactive graphics stream; and

blending the decoded interactive graphics stream with video data; and

one of outputting, to a display, the decoded interactive graphics stream at a designated time when the decoded interactive graphics stream is a normal interactive graphics stream and outputting, to a display, the decoded interactive graphics stream when an activation command is received when the decoded interactive graphics stream is an on-demand interactive graphics stream;

wherein the determining of the type of the read interactive graphics stream includes analyzing a type field included in an interactive composition segment (ICS).

15. The method of claim 14 , wherein the type field is defined so that, when a value of the type field is a first value, the normal interactive graphics stream is indicated, and when the value of the type field is a second value different from the first, the on-demand interactive graphics stream is indicated.

16. A method of reproducing an interactive graphics stream read from a storage medium by a reproducing apparatus, the method comprising:

reading an interactive graphics stream from the storage medium;

decoding the read interactive graphics stream;

determining a type of the read interactive graphics stream, including analyzing a structure of the interactive graphics stream; and

blending the decoded interactive graphics stream with video data; and

one of outputting, to a display, the decoded interactive graphics stream at a designated time when the decoded interactive graphics stream is a normal interactive graphics stream and outputting, to a display, the decoded interactive graphics stream when an activation command is received when the decoded interactive graphics stream is an on-demand interactive graphics stream;

wherein a structure of the normal interactive graphics stream is different from a structure of the on-demand interactive graphics stream; and

wherein the structure of the on-demand interactive graphics stream defines first through nth menu pages.

17. The method of claim 16 , wherein at least one of the menu pages is an initial menu page including an initial button indicating that the on-demand interactive graphics stream is decoded and is ready to be activated, and wherein another of the menu pages includes a button to be displayed after the on-demand interactive graphics stream is activated.