Techniques and tools for signaling the number of reference fields for an interlaced forward-predicted field are described. For example, a video decoder processes a first signal indicating whether an interlaced forward-predicted field has one or two reference fields for motion compensation. If the first signal indicates the interlaced forward-predicted field has one reference field, the decoder processes a second signal identifying the one reference field from among the two reference fields. On the other hand, if the first signal indicates the interlaced forward-predicted field has two reference fields, for each of multiple motion vectors of the interlaced forward-predicted field, the decoder processes a third signal for selecting between the two reference fields. A video encoder performs corresponding signaling.
RELATED APPLICATION INFORMATION
This application claims the benefit of U.S. Provisional Patent Application No. 60/501,081, filed Sep. 7, 2003, the disclosure of which is hereby incorporated by reference. This application is a continuation-in-part of U.S. patent application Ser. No. 10/857,473, filed May 27, 2004, which claims the benefit of U.S. Provisional Patent Application No. 60/501,081, filed Sep. 7, 2003, the disclosures of which are hereby incorporated by reference.
