Spectrographic study of speech samples recorded through Voice Over Internet Protocol (VOIP)

The monumental increase in the use of inexpensive and attractive method of communication such as VOIP has led to a substantial number of problems related to its misuse by criminals. VOIP is need of an hour and VOIP services have been adopted by approximately 10 million people worldwide. VOIP services are ubiquitous, cheap, reduces the call cost, easily accessible, simple infrastructure, scalable and secure. Thus, Internet access and Internet driven phone programs (e.g. Skype); VOIP is becoming popular among terrorists who found such type of transmission more difficult to tap or Intercept. Speech sample transmitted over the internet in packet-switched network is compressed before transmission. Due to this compression, distortion and variation in voice characteristics have been noted when compared with normal speech samples. The present study thus, focuses on the effect of compression on voice sample when routed over the internet through various end devices.