臺灣博碩士論文加值系統

在現代，數位影音市場上最主流的方式便是串流服務。以往的影音串流中，音訊主要都是使用MP3格式或是AAC格式，隨著MP3逐漸要退出市場，近年來在音樂串流技術上也有許多新的格式被使用著。
　　本論文主要為研究新的音訊串流格式Opus中所使用的CELT Layer，並利用MP3跟AAC所使用的Huffman Coding的壓縮方式，取代CELT Layer中使用PVQ(Pyramid Vector Quantizer)以及壓縮PVQ編碼結果的Range Encoding，比較兩者在編碼使用的位元數差異。
　　在這次研究中的實驗主要分成二段，第一段是取得音檔在透過Opus編碼器編碼的過程中，CELT Layer中使用到PVQ以及Range Encoding所處理部分的資料。第二段，將這些資料分別透過MP3使用的Huffman Coding Table以及AAC所使用的Huffman Coding Table編碼後，對這兩種方式與Opus的編碼方法作比較，觀察其中的優劣。

Nowadays, streaming is the particular way to listen to the digital music online. People use the MP3 and AAC format in the past but the MP3 format is retired gradually in recent. Now there are lots of digital audio format in streaming technology and one of them is Opus Codec.
　　In this thesis, we study the CELT Layer in Opus Codec. Use the Huffman Coding in MP3 and AAC to replace the original method PVQ and Range Encoding in CELT. Through this experiment, we can know the compression efficiency between the Range Encoding and Huffman Coding.
　　We let this experiment separate into two parts. First, is obtaining the data from the source file. Second, code these data in MP3’s and AAC’s Huffman Coding method respectively and compare this method’s difference with the original method.

摘　要 i
ABSTRACT ii
誌　謝 iv
目　錄 v
表目錄 vii
圖目錄 ix
第一章 緒論 1
1.1 前言 1
1.2 研究動機與目的 1
1.3 章節編排 2
第二章 Opus Codec標準 3
2.1 基本架構 3
2.2 CELT 4
2.3 Pyramid Vector Quantization 11
2.4 Range Encoding 14
第三章 MP3與AAC使用的資料壓縮技術 20
第四章 實驗及結果 23
4.1 利用MP3的Huffman Code編碼表 27
4.2 利用AAC的Huffman Code編碼表 29
4.3 與Pyramid VQ及Range Encoding之比較 31
第五章 結論與未來展望 35
參考資料 36

[1] J.-M. Valin, T. B. Terriberry, K. Vos, "Definition of the Opus Audio Codec", RFC 6716, 2012.
[2] J.-M. Valin, G. Maxwell, T. B. Terriberry, K. Vos, "High-Quality, Low-Delay Music Coding in the OpusCodec", Accepted for the 135th AES Convention, 2013.
[3] Martin, G., "Range encoding: An algorithm for removing redundancy from a digitised message", Proc. Institution of Electronic and Radio Engineers International Conference on Video and Data Recording, 1979.
[4] Fischer, T., "A Pyramid Vector Quantizer", IEEE Trans. on Information Theory, Vol. 32, pp. 568-583, July 1986.
[5] D. Cadel, G. Parladori, "Pyramid vector coding for high quality audio compression", IEEE International Conference on Acoustics, Speech, and Signal Processing, 1997.
[6] ISO/IEC 11172-3, Coding of Moving Pictures and Associated Audio for Digital Storage Media at up to about 1.5Mbit/s, Part3: Audio, 1992.
[7] ISO/IEC 13818-7, Information Technology – Generic Coding of Moving Pictures and Associated Audio, Part 7: Advanced Audio Coding, 1997.