Image compression and decompression
View Patent ↗Techniques employable to compress and decompress images are presented herein.
1. A method comprising: compressing an image by:
encoding non-repeating pixels as explicit values that are indexes to a color palette and to be block copied from the compressed image to a screen buffer when the explicit values are rendered;
encoding repeating pixels using a repeating command; and
encoding one or more transparent pixels using a skip command that causes rendering of the transparent pixels of the compressed image to be skipped when the compressed image is rendered.
2. A method as described in claim 1 , wherein the palette is provided separately from the compressed image.
3. A method as described in claim 1 , wherein:
the repeating pixels are included in a plurality of consecutive lines of the image; and
the compressing includes encoding the consecutive lines using a single repeat line command.
4. A method as described in claim 1 , wherein the compressing includes:
color matching the image to the palette; and
generating a table of said indices corresponding to pixels in the image.
5. A method as described in claim 1 , wherein the image is included in television content.
6. A method as described in claim 1 , wherein the compressing includes writing a header and image dimensions of the image as a part of the compressed image.
7. A method as described in claim 6 , wherein;
when the one or more transparent pixels include a plurality of transparent pixels in succession, encoding the one or more transparent pixels using a skip command that includes a value indicating a number of said successive transparent pixels; and
otherwise encoding the one or more transparent pixels using a skip command that does not include the value.
8. A method comprising:
examining encoded commands of a compressed image; and
when an explicit command is examined which indicates that a plurality of pixel representations are configured to act as an index to a color palette, copying the pixel representations to a screen buffer as a single block.
9. A method as described in claim 8 , wherein the explicit value also indicates a number of pixels represented by the plurality of pixel representations.
10. A method as described in claim 8 , wherein the image is included in television content.
11. A method as described in claim 8 , wherein the color palette is not included within the compressed image.
12. A method as described in claim 8 , wherein when a skip command is examined, skipping rendering of a number of pixels indicated by the skip command.
13. A method as described in claim 12 , wherein:
when the skip command includes a value, skipping rendering of a number of pixels indicated by the value; and
when the skip command does not include a value, skipping rendering of a single pixel.
14. One or more computer-readable media comprising computer executable instructions that, when executed, direct a computer to compress an image by encoding:
transparent pixels using a skip command that causes rendering of the transparent pixels of the compressed image to be skipped when the compressed image is rendered; and
non-repeating pixels as explicit values that are configured to be block copied from the compressed image to a screen buffer when the explicit values are rendered.
15. One of more computer-readable media as described in claim 14 , wherein the image is configured for display in an onscreen display layer as disposed over a video layer.
16. One of more computer-readable media as described in claim 14 , wherein the computer-executable instructions further direct the computer to encode repeating pixels using a repeating command.
17. One of more computer-readable media as described in claim 16 , wherein the repeating pixels are included in a single line of the image.
18. One of more computer-readable media as described in claim 16 , wherein, wherein:
the repeating pixels are included in a plurality of consecutive lines of the image; and
the compressing includes encoding the consecutive lines using a single repeat line command.
19. One of more computer-readable media as described in claim 14 , wherein the computer is included at a head end that is configured to communicate television content and the compressed image to a plurality of clients over a network.