This　paper　proposes　a　scheme　of　H.264　high-definition　encoder/transcoder.　The　system　is　based　on　ASIC.　Application-specific　high-definition　encoding/transcoding　chip,　software　control　module,　HDMI　interface,　analog　video/audio　input　interface　and　ASI　input/output　interface,　etc.　are　discussed　in　detail　in　this　paper.　The　system　also　provides　the　Ethernet　interface,　which　is　used　for　real-time　monitoring　of　coding/transcoding　system.　The　proposed　scheme　with　the　property　of　good　real-time　and　low　cost　accord　with　the　need　of　high-definition　digital　TV　front-end　system.