Encoders and scheduling methods for macroblock-based adaptive frame/filed (MBAFF) coding are provided. The encoder comprises a first processing engine and a second processing engine. The first processing engine executes a first encoding stage of the frame coding and field coding processes. The second processing engine obtains a processed macroblock (MB) pair or a processed frame and field of a MB pair from the first processing engine, and executes a second encoding stage of the frame coding and field coding processes on the obtained MB pair or obtained frame and field while the first processing engine executes the first encoding stage of the frame coding and field coding processes on a subsequent MB pair or subsequent frame and field.