Abstract
A software based, three resolution video encoder is developed for use in real time, desktop, packet switched videoconferencing over the Internet. The encoder is capable of encoding simultaneously, three streams for three-80x60, 160x120 and 320x240-video resolutions. One stream is for the medium, 160x120, resolution video and consists of intraframe coded conditional replenishment blocks. It has an average bit rate of 44 kbits/s at two frames/s. The compression algorithm that is used is taken from the popular CU-SeeMe videoconferencing tool. Another stream is for the low, 80x60, resolution video and is produced by decimating the medium resolution conditional replenishment blocks. It has an average bit rate of 17 kbits/S at two frames/s. The third stream is a pyramidal difference layer that is used to reconstruct the full, 320x240, resolution video. A "lossy pyramidal coding" method is used to code the pyramidal difference stream and the average rate varies from over 140 kbits/s to less than 10 kbits/s at two frames/s, depending on the desired quality.
Sazzad, Sharif Mohammad (1995). Development of a three resolution video encoder. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1995 -THESIS -S35.