Patent ID: 7646810

Claim:
In a device that implements a video encoder, the device including a processor and memory, a method of encoding video data within a sequence of video frames, the method comprising: with the device that implements the video encoder, encoding at least a portion of a predictive (P) frame relative to at least one reference frame to include motion information associated with the portion of the P frame relative to the at least one reference frame; with the device that implements the video encoder, defining a first direct mode portion of a bidirectionally predictive (B) frame that includes video data predictively correlated to the at least one reference frame based on the motion information associated with the portion of the P frame; with the device that implements the video encoder, defining a second direct mode portion of the B frame that includes video data predictively correlated to the at least one reference frame based on motion information determined using spatial motion vector prediction with motion information for other portions in the B frame; and with the device that implements the video encoder, encoding the first and second direct mode portions of the B frame without including corresponding motion information for the first and second direct mode portions and including mode identifying data that identifies that (a) the first direct mode portion of the B frame can be directly derived using at least the motion information associated with the portion of the P frame relative to the at least one reference frame and (b) the second direct mode portion of the B frame can be directly derived using the motion information determined using spatial motion vector prediction with motion information for other portions in the B frame.