【正文】 ： Research on Digitization Terminal of Audio Broadcast System Based on IP Network in Intelligent Building Master Degree’s Candidate Supervisor: Associated Prof: 摘要 I 摘 要 樓宇 智能化技術(shù)和計算機網(wǎng)絡(luò)技術(shù)的飛速發(fā)展，給傳統(tǒng)的音頻處理和傳輸領(lǐng)域帶來了極大的沖擊。在音頻傳輸領(lǐng)域，計算機網(wǎng)絡(luò)的應(yīng)用，解決了傳統(tǒng)音頻傳輸網(wǎng)絡(luò)中不便于管理，布線復(fù)雜，難以自動切換等缺點。 第一章介紹了樓宇廣播系統(tǒng)的背景和現(xiàn)狀，以及基于網(wǎng)絡(luò)傳輸?shù)男滦蛷V播系統(tǒng)的優(yōu)勢。 第四章介紹了 MP3 音頻編解碼的基本原理。 最后，根據(jù)實際運行情況所存在的缺陷，提出了改進措施和進一步的設(shè)想，期待在后續(xù)工作中完成。 MPEG Decoding 目錄 V 目 錄 摘 要 ........................................................ I 第一章 緒論 ............................................. 1 研究背景 ........................................... 1 研究現(xiàn)狀 ............................................ 2 研究意義 ............................................ 3 主要研究工作 ........................................ 4 第二章 系統(tǒng)硬件及操作系統(tǒng)的移植 ......................... 5 系統(tǒng)硬件概述 ....................................... 5 操作系統(tǒng)的移植 ..................................... 7 交叉開發(fā)環(huán)境的建立與主機的配置 ................. 8 Uboot 的移植 ................................... 9 內(nèi)核的移植、配置和編譯 ........................ 11 制作 RAMdisk ................................... 12 第三章 音頻模塊的驅(qū)動技術(shù) ............................... 14 驅(qū)動程序基礎(chǔ) ...................................... 14 音頻編程接口 ...................................... 17 open 系統(tǒng)調(diào)用 .................................. 17 read 系統(tǒng)調(diào)用 .................................. 18 write 系統(tǒng)調(diào)用 ................................. 18 ioctl 系統(tǒng)調(diào)用 ................................. 18 close 系統(tǒng)調(diào)用 ................................. 19 UDA1341 驅(qū)動程序分析 ............................... 19 UDA1341 的初始化 ............................... 19 緩存區(qū)的設(shè)計 ................................... 20 UDA1341 的 ioctl 系統(tǒng)調(diào)用 ....................... 20 音頻數(shù)據(jù)的播放與錄制 .......................... 22 VI 音頻設(shè)備的打開與卸載 .......................... 22 第四章 音頻解碼技術(shù) ..................................... 24 MP3 編解碼的基本原理 ............................... 24 MP3 解碼過程 ....................................... 28 頭信息和輔助信息的讀取及相應(yīng)處理 ............... 30 比例因子解碼 ................................... 30 霍夫曼解碼 ..................................... 31 非均勻反量化 ................................... 31 立體聲處理 ..................................... 32 混疊信號的消除 ................................. 33 IMDCT .......................................... 34 合成濾波器 ..................................... 35 針對 ARM 的優(yōu)化 .................................... 35 用定點數(shù)來代表浮點數(shù) .......................... 36 算法的改進 ..................................... 37 子程序與宏的結(jié)合 .............................. 39 第五章 網(wǎng)絡(luò)廣播的實現(xiàn)與測試 ............................. 40 在嵌入式 LINUX 系統(tǒng)中實現(xiàn)網(wǎng)絡(luò)廣播 ................... 40 解碼程序 ....................................... 40 創(chuàng)建線程 ....................................... 42 數(shù)據(jù)接收線程和音樂播放線程 .................... 43 數(shù)據(jù)接收線程和音樂播放線程之間的同步 .......... 44 程序運行實例 ................................... 45 系統(tǒng)測試 .......................................... 48 結(jié)論 .................................................... 52 1． 尚待改進之處 ....................................... 52 2．進一步設(shè)想 ......................................... 53 攻讀學(xué)位期間發(fā)表的論文 .................................. 54 目錄 VII 獨創(chuàng)性聲明 .............................................. 55 致 謝 ................................................... 56 參考文獻 ................................................ 57 VIII Catalogue ABSTRACT ..................................................... I CHAPTER 1 INTRODUCE...................................... 1 THE BACKGROUND OF RESEARCH .......................... 1 THE SITUATION OF RESEARCH ........................... 2 THE SIGNIFICANCE OF RESEARCH ........................ 3 THE MAIN CONTENTS OF RESEARCH ....................... 4 CHAPTER 2 SYSTEM HADRWARE AND OPERATING SYSTEM TRANSPLANT ........................................................ 5 THE DESCRIPTION OF SYSTEM HARDWARE .................. 5 THE TRANSPLANTION OF OPERATING SYSTEM ............... 7 Integrated Development Enviroment and Configuration Of Host ............................................... 8 The Transplantation of Uboot .................. 9 Configuration, Portint and Compile of Kernel .. 11 RAMdisk making................................. 12 CHAPTER 3 THE DRIVER OF AUDIO DEVICE ................... 14 THE FOUNDATION OF AUDIO DEVICE ..................... 14 APPLICATION PROGRAMMING INTERFACE OF AUDIO DEVICE .. 17 open System Calls ............................. 17 read System Calls .............................. 18 write System Calls ............................. 18 ioctl System Calls ............................. 18 close System Calls ............................. 19 THE ANALYSIS OF UDA1341 DRIVER ..................... 19 The Initialization of UDA1341 ................. 19 Buffer Design.................................. 20 目錄 IX ioctl System Calls of UDA1341 ................. 20 Play and Record of Audio Device ............... 22 Open and Close of Audio Device ................ 22 CHAPTER 4 THE TECHNOLOGY OF AUDIO DECODING ............. 24 THE PRINCIPLE OF MP3 ENCODING AND DECODING ......... 24 THE PROCESS OF MP3 DECODING ........................ 28 The Processing of Header Information and Side Informatin .......................................... 30 Scale Factor Decoding ......................... 30 Huffman Decodi