Study Of ITU-TG.729 Coder And Decoder And Its Arithmetic Optimized In TMS320C54x

G.729 agreement is made by ITU_T to realize speech code with good quality at the rate of 8kb/s. and used widely because of its good quality and low code rate. In VoIP gateway, G.729 agreement is used to realize instant speech code process.The realized emphasis of G.729 arithmetic lies in realization of coder and decoder and collection and storage of data .ITU put forward the agreement as well as its software reference application. Written with ANSI.C, the software can be translated and run on many hardware platform. However, the software is not optimized to any platformThe article briefly introduces some basic techniques of G.729 and states the theory of coder and decoder in details. Based on the result of testing the capability of coder and decoder, it concludes that G.729 meets the basic need of long-distance quality in most cases.The article analyses emulated C language software of decoder that is CS-ACELP with 16bit fixed point, then come to conclusion that the software realizes the main function of G729 agreement, but it fails to provide concealment of frame erasures.To solve the problem of optimizing, the article uses the instruction of TMS320C54x to rewrite C language process. Firstly, storage section is optimized, then code by optimizing equipment at last C language process is rewritten in compilation process with the instruction ofTMS320C54x.In the optimizing test, 675 frames speech information is used as test data to test its coded and decoded time. The test is done 10 times and the data .from the test is averaged in order to make the system affect speech information consistently. From the result of the test, it reaches the conclusion that postponement time between coder and decoder is less than15ms, which proves that the optimizing method can be used in reality.