Video coding methods and apparatuses are provided that make use of various models and/or modes to significantly improve coding efficiency especially for high/complex motion sequences. The methods and apparatuses take advantage of the temporal and/or spatial correlations that may exist within portions of the frames, e.g., at the Macroblocks level, etc. The methods and apparatuses tend to significantly reduce the amount of data required for encoding motion information while retaining or even improving video image quality.
RELATED PATENT APPLICATIONS
This U.S. Non-provisional Application for Letters Patent claims the benefit of priority from, and hereby incorporates by reference the entire disclosure of, co-pending U.S. Provisional Application for Letters Patent Ser. No. 60/376,005, filed Apr. 26, 2002, and titled "Video Coding Methods and Arrangements".
This U.S. Non-provisional Application for Letters Patent further claims the benefit of priority from, and hereby incorporates by reference the entire disclosure of, co-pending U.S. Provisional Application for Letters Patent Ser. No. 60/352,127, filed Jan. 25, 2002.
In the method of determining a motion vector for deriving motion vectors of a bi-predictive image block, one of a first and second motion vector of a co-located image block for a bi-predictive image block is selected as a motion vector for deriving motion vectors of the bi-predictive image block.
In the method of determining a motion vector for deriving motion vectors of a bi-predictive image block, a list 1 motion vector of a co-located image block for a bi-predictive image block is selected as a motion vector for deriving motion vectors of the bi-predictive image block when the co-located image block only has a list 1 motion vector.
In one embodiment, the method includes selecting the list 1 motion vector of the co-located block in a first list 1 reference picture as the motion vector for deriving list 0 and list 1 motion vectors of the bi-predictive block, if the co-located block only has the list 1 motion vector. The first list 1 reference picture is a type of reference picture permitted to be located temporally before or after a current picture, and the selected list 1 motion vector points to a second list 1 reference picture which is a reference picture of the first list 1 reference picture. Also, the current picture includes the bi-predictive block. The selected motion vector is scaled based on a temporal distance between the current picture and the first list 1 reference picture, and the motion vector of the bi-predictive block is derived based on the scaled motion vector.
Request bits estimation for a Wyner-Ziv codec is described. In one aspect, and prior to communicating Wyner-Ziv parity bits to a Wyner-Ziv decoder, an estimated total number of parity bits to send to the Wyner-Ziv decoder are determined. This estimated number of parity bits allows the Wyner-Ziv decoder to reconstruct a frame of different coded content using the Wyner-Ziv parity bits such that the reconstructed frame will meet particular quality criteria. This estimated number of parity bits is determined independent of a request-bits feedback loop between the Wyner-Ziv coder and the Wyner-Ziv decoder. The estimated number of parity bits is communicated to the Wyner-Ziv decoder for reconstruction and presentation of the frame to a user.
