| 摘要 |
A mechanism for performing a motion vector search at a current block within a current frame of video data. For each test vector position v of a plurality of test vector positions, compute a rate distortion value J(v) based on a combination of a distortion value D(v) and a bit cost value R(v,p,C). The distortion value D(v) represents a measure of distortion of the current block relative to a corresponding block Bv in the reference frame. The bit cost value R(v,p,C) depends on the test vector position v, a prediction vector p for the current block and a set C of one or more vectors c1, c2, . . . , cn. The one or more vectors c1, c2, . . . , cn are estimates (or predictions) of statistically-popular motion vectors for the current frame. The test vector position v* that gives a minimum rate-distortion value J(v*) is selected as the motion vector for the current block. |
| 主权项 |
1. A method for encoding video data including a frame sequence, the method comprising:
encoding a current frame of the frame sequence with respect to a reference frame of the frame sequence, wherein said encoding the current frame includes sequentially processing a plurality of blocks of the current frame according to an ordering of the blocks, wherein processing a current block includes performing a motion vector search for the current block over a plurality of test vector positions, wherein said performing the motion vector search includes:
for each test vector position v of the plurality of test vector positions, computing a rate distortion value J(v) based on a linear combination of a distortion value D(v) and a bit cost value R(v,p,C), wherein the distortion value D(v) represents a measure of distortion of the current block relative to a corresponding block Bv in the reference frame, wherein the corresponding block Bv has a position in the reference frame that is defined by the test vector position v and a position of the current block in the current frame, wherein the bit cost value R(v,p,C) depends on the test vector position v, a prediction vector p for the current block and a set C of one or more vectors c1, c2, . . . , cn, wherein the vectors c1, c2, . . . , cn are estimates of statistically popular motion vectors for the current frame;selecting a test vector position v* from said plurality of test vector positions that gives a minimum rate-distortion value, wherein the bit cost value R(v,p,C) is determined by:
computing a baseline bit cost value R0(v,p) that represents a bit cost for encoding a difference vector d=v−p;computing a bias value ΔR(v,C) based on a bias function AR that has a local minimum at each of the vectors c1, c2, . . . , cn, wherein the bias function ΔR approaches zero as the difference vector d approaches zero; andadding the baseline bit cost value R0(v,p) and the bias value ΔR(v,C) to obtain the bit cost value R(v,p,C). |
