Implementation and Evaluation of DSP-Assisted Synchronization Algorithms for Heterogeneous Teleconferencing
Date Issued
2010
Date
2010
Author(s)
Ke, Jhu-Ze
Abstract
The video conference among heterogeneous network could not only provide stable connection through PSTN network but also provide good experience by transmitting picture frames among IP network. However, the audio and video streams might be asynchronous among heterogeneous network. In our previous work, algorithms based on digital speech processing techniques are provided to deal with the problem. However, the algorithms are not evaluated on the real system. In this thesis, synchronization algorithms of previous research are implemented and evaluated on the existing hardware. In hardware part, we use dual mode wireless card and audio cable to make notebook have the same capability as dual mode mobile phone which can communicate with both PSTN(GSM) and IP(WLAN) networks at same time. In software part, we add the synchronization modules in existing softphone to measure the delay difference between networks and postpone the waveform if needed. After the algorithms of our previous work are implemented and evaluated upon the prototype, we found both accuracy and execution time of our previous work should be improved for real-time system. Accelerating methods are proposed in thesis to resolve the problem. We proposed two accelerating algorithms using feature of speech formant after analyzing speech production model. We found the proposed algorithm would only spend one-tenth execution time of original algorithm without sacrificing any accuracy after implementation our proposed algorithm on existing hardware. Therefore, we evaluate the possibility of resolving audio/video conference asynchrony in heterogeneous networks by digital speech processing technology.
Subjects
DSP
formant
Heterogeneous Teleconferencing
Type
thesis
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