Moving　object　is　too　fast　or　a　long　exposure　of　a　moving　object　will　cause　a　＂streak＂　of　the　moving　object　in　the　recorded　video　sequence.　In　this　case,　it＇s　hard　to　recognize　the　detail　of　objects,　and　not　necessary　to　encode　the　detail　of　motion　which　usually　consumes　lots　of　bits,　especially　under　the　situation　of　high　resolution　sequence.　In　this　paper,　we　propose　an　up-sampling　based　encoding　method　for　the　high　resolution　sequence　with　rapid　motion.　When　rapid　motion　is　detected　in　the　current　sequence,　only　a　down-sampled　version　is　encoded　and　sent　to　the　decoder　to　save　bit-rate.　The　decoder　recovery　the　high　resolution　sequence　through　up-sampling　the　received　low　resolution　bit　stream.　To　avoid　the　visible　artifacts　and　merge　the　synthesis　into　nowadays＇　I,　P,　B　frame　based　codec,　a　synthetic　region　selection　strategy　is　employed,　which　can　help　achieving　a　smooth　transition　between　the　synthetic　frames　and　the　adjacent　non-synthetic　frames.　This　scheme　has　been　integrated　into　H.264,　and　experimental　results　show　large　amount　of　bit-rate　is　saved　at　similar　visual　quality　levels　compared　with　H.264.