Motion compensated de-blocking
Digital noise removal methods and systems for picture quality improvement on next generation high quality set-top-box and digital TV SOCs is disclosed with particular to a de-blocking method and system that is effective on on-grid and off-grid blocky artifacts generated by lossy video compression standards. Blocky artifacts are filtered by extracting motions vectors for a current pixel block, calculating off-grid positions based on the extracted motion vectors, and applying de-blocking filtering along the calculated off-grid positions. The methods and systems can further skip filtering on-grid blocky artifacts to be filtered by an on-grid de-blocking filter known in the art.
1. A method of motion compensated de-blocking of a current picture of a video, the method comprising:
extracting at least one motion vector for a current pixel block of the current picture;
operating a blocking noise positions calculation unit for calculating at least one position for the current pixel block and based on the extracted at least one motion vector, the calculating of the at least one position comprising
retrieving decoder information and at least one prior stored position,
determining if the current pixel block is intra-coded based upon the retrieved decoder information, and
if so, then resetting the at least one position of the current pixel block to a zero value, and
otherwise
determining if the current pixel block is a skipped transformation, and
if so, then calculating the at least one position of the current pixel block, and
otherwise keeping the at least one prior stored position,
determining if the current pixel block is an anchor frame, and
if so, then storing the at least one calculated position, and
otherwise keeping the at least one prior stored position; and
operating a de-blocking filter for applying de-blocking filtering along the at least one calculated position.
2. The method of claim 1 , wherein the calculating of the at least one position based on the extracted at least one motion vector comprises calculating at least one off-grid position.
3. The method of claim 1 , wherein the extracted at least one motion vector is extracted from the current pixel block and from at least one co-sited pixel block of at least one previous picture of the video.
4. The method of claim 1 , wherein the extracted at least one motion vector is extracted from pixel blocks of the current and previous pictures of the video that are surrounding the current pixel block.
5. The method of claim 2 , wherein the calculating of the at least one off-grid position is further based on at least one of current block coded information, coded block information, skipped transform information, and previously determined off-grid positions.
6. The method of claim 2 , further comprising applying de-blocking filtering to on-grid positions of the current picture.
7. The method of claim 1 , wherein the de-blocking filtering is applied independently using at least one of horizontal and vertical motion, the de-blocking filtering being on at least one of a luma and chroma.
8. The method of claim 1 , wherein the retrieving of the decoder information comprises:
retrieving a coded picture type;
retrieving intra/inter coded information;
retrieving coded block pattern and skipped transform information; and
retrieving the at least one motion vector from the current pixel block of the current picture and co-sited pixel blocks of at least one previous decoded picture.
9. A system for motion compensated de-blocking of a current picture of a video, the system comprising:
a processor and memory coupled thereto and configured to:
receive an extracted at least one motion vector;
calculate at least one position for a current pixel block of the current picture and based on the extracted at least one motion vector, the calculating of the at least one position comprising
retrieving decoder information and at least one prior stored position,
determining if the current pixel block is intra-coded based upon the retrieved decoder information, and
if so, then resetting the at least one position of the current pixel block to a zero value, and
otherwise
determining if the current pixel block is a skipped transformation, and
if so, then calculating the at least one position of the current pixel block, and
otherwise keeping the at least one prior stored position,
determining if the current pixel block is an anchor frame, and
if so, then storing the at least one calculated position, and
otherwise keeping the at least one prior stored position; and
apply de-blocking filtering along the at least one calculated position.
10. The system of claim 9 , wherein the calculating of the at least one position based on the extracted at least one motion vector comprises calculating at least one off-grid position.
11. The system of claim 9 , wherein the extracted at least one motion vector is extracted from the current pixel block and from at least one co-sited pixel block of at least one previous picture of the video.
12. The system of claim 9 , wherein the extracted at least one motion vector is extracted from pixel blocks of the current and previous pictures of the video that are surrounding the current pixel block.
13. The system of claim 9 , wherein the de-blocking filtering is applied independently using at least one of horizontal and vertical motion, the de-blocking filtering being on at least one of a luma and chroma.
14. The system of claim 10 , wherein the calculating the of the at least one off-grid position is further based on at least one of current block coded information, coded block information, skipped transform information, and previously determined off-grid positions.
15. The system of claim 10 , wherein said processor and memory are configured to apply de-blocking filtering to on-grid positions of the current picture.