| Summary: | 碩士 === 國立高雄第一科技大學 === 電腦與通訊工程所 === 91 === Internet application has been changing day after day from searching and transmitting simple data to multimedia applications. It has become a home appliance rather than a professional tool only. It serves us as telephone, television, radio, etc, and Internet Phone is very popular at the moment.
The Internet Phone, PC to PC communication, discussing in this paper is based on VoIP, including critical technologies such as network programming, voice processing, speech codec, and real time transmission. All these techniques are practiced perfectly in Speak Freely.
Speak Freely, an Internet Phone software, enable you to have a free talk on Internet, was originally written by John Walker in 1991. In 1997, John Walker agreed Brian C. Wiles officially taking over the project. With the spirit of Open Source SoftwareTM, he licensed this program under the GNU General Public License.
The specific of Speak Freely is including client-server operateion, it provides voice buffer process, several speech codec algorithms to adapt different bandwidth environments, and three optional protocols.
This thesis is to probe the critical technologies of Internet Phone by discussing the example of Speak Freely. Modifying some subroutines for observing how it works, knowing the specific of algorithms, and analyzing its reason would be seen in the following pages.
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