Patent ID: 7630438

Claim:
In a computing device that implements a video decoder, the computing device including a processor and memory, a method of decoding video, the method comprising: with the computing device that implements the video decoder, decoding a current direct-mode macroblock in a current interlaced bi-directionally predicted field, including: determining that a co-located macroblock in a temporally future interlaced predicted field was encoded using four-motion-vector encoding; determining one or more motion vectors of the co-located macroblock; and calculating a motion vector to use in direct mode scaling operations for the current direct-mode macroblock, including favoring dominant polarity for the one or more motion vectors of the co-located macroblock when calculating the motion vector by: determining whether more of the one or more motion vectors of the co-located macroblock reference a first reference field or a second reference field; if more of the one or more motion vectors of the co-located macroblock reference the second reference field, computing the motion vector to use in direct mode scaling operations using those of the one or more motion vectors of the co-located macroblock that reference the second reference field; and otherwise, computing the motion vector to use in direct mode scaling operations using those of the one or more motion vectors of the co-located macroblock that reference the first reference field; and with the computing device that implements the video decoder, reconstructing the current interlaced bi-directionally predicted field using the decoded current direct-mode macroblock.