【正文】 要 編碼 主要有三方面的含義：模擬信號的數(shù)字化過程、數(shù)據(jù)的壓縮過程和數(shù)據(jù)的加密過程。 本文先對已有的視頻、音頻的編解碼原理、機(jī)制和主流編解碼框架進(jìn)行了整理和研究，然后根據(jù)已有原理嘗試應(yīng)用新的思想開發(fā)了一種音視頻 編碼解碼方法，通過運用 DirectShow和 VC++作為開發(fā)工具，引用 Zlib 函數(shù)庫來實現(xiàn)了這種音視頻編碼解碼方法，并通過運行測試對新的編解碼方法對 CPU 運行的影響、編碼后的文件大小和網(wǎng)絡(luò)傳輸時間的花費三方面進(jìn)行了測試和總結(jié) 。 無損 壓縮音視頻的編碼方式可應(yīng)用于對于圖像還原有較高要求的領(lǐng)域。 Decoding 音視頻編碼解碼研究 III 目 錄 摘 要 ............................................................................................................................. I Abstract............................................................................................................................... II 一、引言 ............................................................................................................................ 1 二、音視頻編解碼原理 .................................................................................................... 2 （一）視頻編碼原理 ........................................................................................................ 2 1. 去時域冗余信息 ................................................................................................... 2 2. 去幀域冗余信息 ................................................................................................... 2 （二）視頻編碼機(jī)制 ........................................................................................................ 3 ................................................................................................................. 4 ................................................................................................................. 4 （三）主流視頻編碼框架 ................................................................................................ 5 1. MPEG ..................................................................................................................... 5 2. ..................................................................................................................... 5 3. 微軟 windows media............................................................................................. 6 4. QuickTime.............................................................................................................. 6 5. Real Media ............................................................................................................. 6 （四）視頻解碼原理 ........................................................................................................ 6 （五）音頻編碼原理 ........................................................................................................ 6 （六）音頻 編碼機(jī)制 ........................................................................................................ 6 （七）主流音頻編碼框架 ................................................................................................ 7 1. WAVE .................................................................................................................... 7 2. MP3 ........................................................................................................................ 7 3. OGG ....................................................................................................................... 7 4. WMA...................................................................................................................... 8 5. RA .......................................................................................................................... 8 （八）音頻解碼原理 ........................................................................................................ 8 三、音視頻編碼解碼實現(xiàn) ................................................................................................ 9 （一）系統(tǒng)分析 ................................................................................................................ 9 1. 開發(fā)工具及函數(shù) ................................................................................................... 9 工作模型 ............................................................................................. 9 3．編碼器模型 ........................................................................................................ 10 音視頻編碼解碼研究 IV 4．解碼器模型 ........................................................................................................ 11 （二）壓縮算法 .............................................................................................................. 11 1．編碼解碼算法 .................................................................................................... 11 2． Deflate 算法工作原理 ....................................................................................... 12 （三）編解碼設(shè)計 .......................................................................................................... 14 1． Filter 的注冊 ...................................................................................................... 14 2．主要編碼函數(shù) .................................................................................................... 17 3．主要解碼函數(shù) .................................................................................................... 18 （四）性能比照 .............................................................................................................. 19 1． CPU 運行效率比較 ........................................................................................... 19 2．壓縮比 ................................................................................................................ 19 3．壓縮實時速率比較 ............................................................................................ 21 結(jié) 論