Rendering scrolling captions
A method, system, and computer program product for rendering scrolling captions for media content includes a processor to receive a first request to display a first line of text associated with a media file. The processor may generate a framebuffer object (FBO) and a first texture per-line (TPL) for the first line of text. The processor may draw one or more glyphs on the first TPL, and render the first TPL in a first position of the FBO. The processor may receive a second request to display a second line of text. The processor may generate a second TPL for the second line of text, draw one or more glyphs on the second TPL, render the first TPL in a second position and the second TPL in the first position.
1. A method for rendering scrolling captions for media content, the method comprising:
receiving, by a computing device, a first request to display a first line of text associated with a media file, the first line of text being caption data for a first portion of audio content of the media file;
generating, by the computing device, a framebuffer object (FBO), the FBO being an active framebuffer for the media file;
generating, by the computing device, a first texture per-line (TPL) for the first line of text;
drawing, by the computing device, one or more glyphs on the first TPL;
rendering, by the computing device, the first TPL in a first position of the FBO;
displaying, by the computing device, the first TPL on a display at the first position;
receiving, by the computing device, a second request to display a second line of text associated with the media file, the second line of text being caption data for a second portion of the audio content of the media file;
generating, by the computing device, a second texture per-line (TPL) for the second line of text;
drawing, by the computing device, one or more glyphs on the second TPL;
rendering the first TPL in a second position and the second TPL in the first position; and
displaying the second TPL on the display in the first position and the first TPL in the second position.
2. A method according to claim 1 , wherein the first TPL and the second TPL are bound to the FBO.
3. A method according to claim 1 , wherein the first TPL and the second TPL are generated using OpenGL.
4. A method according to claim 1 , wherein the displaying the second TPL on the display in the first position and the first TPL in the second position comprises:
scrolling, by the computing device, the first TPL from the first position to the second position on the display.
5. A method according to claim 1 , wherein the second position is partially visible on the display.
6. A method according to claim 1 , comprising:
storing, by the computing device, the first TPL and the second TPL in an active TPL list, the active TPL list stored in a memory of the computing device.
7. A method according to claim 6 , comprising:
determining, by the computing device, the second position is not visible on the display; and
removing, by the computing device, the first TPL from the active TPL list.
8. A system for rendering scrolling captions for media content, the system comprising:
a processor configured to receive a first request to display a first line of text associated with a media file, the first line of text being caption data for a first portion of audio content of the media file;
the processor configured to generate a framebuffer object (FBO), the FBO being an active framebuffer for the media file,
the processor configured to generate a first texture per-line (TPL) for the first line of text;
a graphics processing unit of the processor configured to:
draw one or more glyphs on the first TPL;
render the first TPL in a first position of the FBO;
a display unit configured to display the first TPL on a display at the first position;
the processor configured to receive a second request to display a second line of text associated with the media file, the second line of text being caption data for a second portion of the audio content of the media file;
the processor configured to generate a second texture per-line (TPL) for the second line of text;
the graphics processing unit of the processor configured to:
draw one or more glyphs on the second TPL;
render the first TPL in a second position and the second TPL in the first position; and
the display unit configured to display the second TPL on the display in the first position and the first TPL in the second position.
9. A system according to claim 8 , wherein the first TPL and the second TPL are bound to the FBO.
10. A system according to claim 8 , wherein the first TPL and the second TPL are generated using OpenGL.
11. A system according to claim 8 , wherein the display unit is configured to display the second TPL on the display in the first position and the first TPL in the second position comprises:
the processor configured to scroll the first TPL from the first position to the second position on the display.
12. A system according to claim 8 , comprising:
a memory configured to store the first TPL and the second TPL in an active TPL list, the active TPL list.
13. A system according to claim 12 , comprising:
the processor configured to determine the second position is not visible on the display; and
the processor configured to remove the first TPL from the active TPL list stored in the memory.
14. A computer program product for rendering scrolling captions for media content, the computer program product comprising:
a non-transitory computer-readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method, comprising:
receiving, by a computing device, a first request to display a first line of text associated with a media file the first line of text being caption data for a first portion of audio content of the media file;
generating, by the computing device, a framebuffer object (FBO), the FBO being an active framebuffer for the media file;
generating, by the computing device, a first texture per-line (TPL) for the first line of text;
drawing, by the computing device, one or more glyphs on the first TPL;
rendering, by the computing device, the first TPL in a first position of the FBO;
displaying, by the computing device, the first TPL on a display at the first position;
receiving, by the computing device, a second request to display a second line of text associated with the media file, the second line of text being caption data for a second portion of the audio content of the media file;
generating, by the computing device, a second texture per-line (TPL) for the second line of text;
drawing, by the computing device, one or more glyphs on the second TPL;
rendering the first TPL in a second position and the second TPL in the first position; and
displaying the second TPL on the display in the first position and the first TPL in the second position.
15. A computer program product according to claim 14 , wherein the first TPL and the second TPL are bound to the FBO.
16. A computer program product according to claim 14 , wherein the first TPL and the second TPL are generated using OpenGL.
17. A computer program product according to claim 14 , wherein the displaying the second TPL on the display in the first position and the first TPL in the second position comprises:
scrolling, by the computing device, the first TPL from the first position to the second position on the display.
18. A computer program product according to claim 14 , wherein the second position is partially visible on the display.
19. A computer program product according to claim 14 , comprising:
storing, by the computing device, the first TPL and the second TPL in an active TPL list, the active TPL list stored in a memory of the computing device.
20. A computer program product according to claim 19 , comprising:
determining, by the computing device, the second position is not visible on the display; and
removing, by the computing device, the first TPL from the active TPL list.