Abstract: A reference picture is processed to generate, first, second and third pictures. The first picture has a lower resolution than the second picture and the second picture has a lower resolution than the third picture. Using independent starting positions, first and second stage field motion estimation (motion vector) searches are preformed using the first and second pictures, respectively. By performing the first stage field motion estimation search, a first field motion vector candidate is obtained. By performing the second stage field motion estimation search, a second field motion vector candidate is obtained. Using at least one of the first and second field motion vector candidates as a starting position and the third picture, a third stage field motion estimation search is performed. Alternatively, a first stage field motion estimation search is performed using the first picture to obtain a first motion vector from a top reference field and a second motion vector from a bottom reference field.

Abstract: A method and apparatus for performing multi-stage motion estimation on an input video sequence to be encoded. An original image in the video sequence, such as a CCIR601 image, is preprocessed to generate first, second and third reduced resolution images which may be a QQSIF image, a QSIF image and a SIF image, respectively, which are 1/64 size, 1/16 size and 1/4 size, respectively, relative to the original CCIR601 image. A first stage motion vector search is performed on the 1/64 size QQSIF image using a (0,0) motion vector starting point and a first search range suitable for detecting global motion. A second stage motion vector search is performed on the 1/16 size QSIF image using the (0,0) starting point and a second search range smaller than the first search range and suitable for detecting local motion.