Method of filtering pixels in a video encoding process
View Patent ↗A method and apparatus, particularly suited to SIMD instruction sets, to filter streaming video information encoded under a predictive encoding algorithm specified under video encoding standards, such as MPEG 4 or H.264/AVC. The filtering operation de-blocks or removes unwanted borders in the perceived video. During the filtering process, a series of filtering mask is generated based on temporal and spatial statistics of predictive encoded video information, which is then recursively applied to the video in order to gate filtered or unfiltered video to an output channel according to coefficients of the masks. The filtering mask effectively yields a decision or rule-based map that transforms the video on a pixel-by-pixel basis thereby avoiding complex and processor-intensive decision tree logic customarily required to process individual pixels of successive macroblocks that may have different filtering requirements.
1. In a method of real-time pre-filtering of pixel groups of streaming video information on a video channel encoded under a predictive encoding standard and processed utilizing SIMD instructions to transform individual pixels of said pixel groups according to threshold values derived during said predictive encoding, said method comprising:
obtaining statistical parameters from respective pixel groups of said streaming video information,
generating, in real time, a pixel transformation filtering mask based on said statistical parameters,
employing said filtering mask to said pixel groups in conjunction with SIMD instructions to transform individual pixels of said pixel groups of said streaming video information to produce a desired video output on the video channel in response to a value of statistical parameters exceeding a predetermined threshold value and otherwise passing the streaming video to the video channel without filtering when said threshold is not exceeded wherein coefficients of said filter mask are mapped to a respective threshold value and at least one statistical parameter comprises a number of non-zero quantized coefficients,
encoding said pixel groups under said predictive coding, and
sending said encoded pixel group over a video channel while continuing pre-filtering of said streaming video whereby to enable transmission of said encoded video information in real time.
2. The method of claim 1 , wherein said video encoding standard is specified by H.264/AVC.
3. The method of claim 2 , wherein said statistical parameters further comprises a quantization scale.
4. The method of claim 3 , further comprising:
selectively applying the filtering mask to transform pixel group values produced during filtering to influence the level of filtering of individual pixels.
5. The method of claim 4 , further comprising:
modifying the filtering mask before selectively applying the filtering mask to filtered values produced during filtering to influence the level of filtering of individual pixels.
6. The method of claim 4 , further comprising:
modifying the filtering mask before selectively applying the filtering mask to threshold values produced during filtering to influence the level of filtering of individual pixels.
7. The method of claim 1 , wherein said filtering mask comprises a transform map that defines decision logic to transform individual pixels of a pixel group.
8. A method of real-time filtering and pre-processing streaming video information prior to encoding under a predictive encoding algorithm prior to sending over a communication channel in order to filter individual elements of pixel groups, said method comprising:
obtaining statistical parameters from video information prior to encoding under said predictive encoding algorithm,
generating in real-time a set of filtering masks based on said statistical parameters,
selectively utilizing said filtering mask to filter individual elements of said pixel groups by gating one of filtered and unfiltered pixel group over a video channel according to a whether an absolute value of statistical parameters in respective groups of pixels exceeds a threshold wherein coefficients of said filter mask are mapped to a respective threshold value and at least one statistical parameter comprises a quantization scale,
subsequently compressing said pixel groups according to said predictive encoding algorithm, and
sending filtered and compressed video stream over a video channel to a receiver for decoding said video stream.
9. The method of claim 8 , further including utilizing a predictive encoding algorithm defined under H.264/AVC.
10. The method of claim 9 , further including utilizing single-instruction-multiple-data instructions in said generating and utilizing steps.
11. The method of claim 8 , wherein at least one of said statistical parameters comprises a number of non-zero quantized coefficients.