基於Screen Video Codec 2桌面分享之編解碼演算法最佳化

Encoder Optimization for Desktop Sharing Using Screen Video Codec 2

張志揚(Chih-Yang Chang)

指導教授 ： 郭天穎

國立臺北科技大學/電資學院/電機工程系所/碩士(2014年)

摘要

Big Blue Button是一個開放源視訊會議的軟體，這個軟體內有多種功能，如:桌面分享、視訊分享、音訊分享、PPT或PDF分享…等等。Big Blue Button採用Adobe的Screen Video Codec2(簡稱SVC2)桌面分享視訊壓縮規範來進行桌面分享。
本論文在不改變SVC2串流格式下，是針對該軟體進行改進，改進方法，包括了畫面變化偵測機制的改進、畫面重傳時機的選擇、色彩量化的使用、畫面縮小演算法的改進、畫面擷取管線化(pipeline)的使用、畫面擷取的型態轉型函數之更換等機制。實驗結果證明本論文提出的方法在圖框率與頻寬的使用上皆可獲得改善。

關鍵字

桌面分享 ； 色彩量化 ； 視訊會議 ； 管線化 ； Screen Video Codec

並列摘要

Big Blue Button (BBB) is open-source software for video-conferencing, which provides sharing functions for desktop, video, audio, PPT and PDF, etc. For the desktop sharing, BBB adopts an encoder tailored to the Screen Video Codec 2(SVC2) of Adobe’s standard.
The goal of this work is to improve the encoder performance of BBB desktop sharing, while keeping the output video stream conforming to SVC2. This work improves BBB in many aspects, including detection of frame change, decision of frame replenishment, quantization of color, reduction of frame scaling complexity, pipeline structure of screen capture, type conversion of the capture frames. Experiment results shows the frame rate and bandwidth is improved by our proposed method.

並列關鍵字

Desktop Sharing ； color quantization ； video-conferencing ； pipeline ； Screen Video Codec

參考文獻

[1]S. Ichimura and Y. Matsushita, "Lightweight Desktop-Sharing System for Web Browsers," Third International Conference on Information Technology and Applications, 2005, pp. 136-141

[2]G. Kiss, “Using web conference system during the consultation hours”, 7th IEEE International Symposium on Applied Computational Intelligence and Informatics, 2012, Timisoara, Romania, 2012.

[3]G. Kiss, “Comparison of traditional and web-based education – case study ‘BigBlueButton’ ”, Proceedings of the 2012 International Symposium on Information Technology in Medicine and Education, Hokkaido, Japan, IEEE Catalog Number: CFP1253E-PRT ISBN:978-1-4673-2016-8, pp: 224-227, IEEE Xplore digital library Digital Object Identifier:10.1109/ITiME.2012.6291286, 2012.

[4]Adler32,[online] http://en.wikipedia.org/wiki/Adler-32

[5]BigBlueButton,[online] http://bigbluebutton.org/