數位音訊編碼已經非常流行而且被廣泛的應用在各種不同的領域中，在本論文中會針對音訊編碼的應用提出兩個主題。在第一個主題中，近年來，多媒體資料的搜尋與索引技術受到愈來愈多的注意，尤其是在內涵式搜尋領域中。在音訊這個範圍裡，許多的研究皆專注在MIDI或WAV這些未壓縮的音樂格式上，很少會針對壓縮過的音樂格式這個領域來探討。然而，MP3在目前已是一個重要且受歡迎的音樂格式，許多網路或是個人電腦中所流通的都是以MP3為主。在本篇論文中，我們提出了一個利用以歌找歌方式並且以MP3為主的內涵式音樂搜尋系統。我們將MP3中的次頻帶值取出來當成特徵值，並且利用量化樹索引方法及旋律線擷取方法將所取出的特徵值建成我們要的索引資料，最後再利用這些索引資料作為輸入歌曲片段與資料庫歌曲之相似度比對的依據。此外我們將整個內涵式音樂搜尋系統移植到以ARM為主的嵌入式系統平台上來做實現，整個系統的評估實驗分別進行在PC及嵌入式系統平台上，大約有95%的機率可以在前三首歌中找到。 第二個主題部分則是針對軟硬體共同設計做介紹，因為在一個SoC 的平台上可以同時提供通用處理器所具備的高彈性優點以及客製化硬體的高效能、低功率消耗特性，所以我們特別提出軟硬體共同設計的方式來實現多種標準數位音訊解碼器。分別有MP3、AC-3、AAC這三種標準。首先，我們採用開放源碼中的32 位元處理器 — OpenRISC 1200 (OR1200) 為基底，安裝完整的工具鏈(ToolChain)及建立軟硬體的模擬環境，最後，符合匯流排規格並成功在Xilinx FPGA板和Cell-Base驗證其功能。 Digital audio coding is popular and has been applied in many areas. In this thesis is focus on audio coding and brings two contributions. First, the searching and indexing techniques for multimedia data are getting more attention in the area of multimedia databases. As many research works were done on the content-based retrieval of MIDI or waveform format music, less attention was received on the compressed domain audio data. As the explosive growth of internet, MP3 audio has become one of the most important and popular media. Most of the audio accessed from database of Internet are all compressed on MP3 domain, not raw data or even low quality MIDI audio. The content-based retrieval of audio example on MP3-based (MPEG 1 layer III) digital music archive is considered. In the proposed approach, the sub-band coefficients (SBC) in a MP3 frame are used. These values are extracted from the MP3 decoder to compute the MP3 features for indexing the MP3 objects. A quantization-tree indexing (QTI) and the melody-line pitch tracking (MLPT) method are also proposed for indexing MP3 objects. These indexes are used to measure the similarity between MP3 objects. Evaluations on a content-based MP3 retrieval system are performed on the pc version and platform-based embedded system version which indicate the proposed approach can achieve a good performance. Second, an SoC-Based hardware/software co-design method for a multi-standard audio decoder. It is developed to support the audio standards of AAC LC profile, Dolby AC3 and MPEG-1 Layer 3. We present the approach not only for the characteristics of the algorithm, but also provide the numerical decision for evaluation of the various approaches. The overall system is first analyzed and profiled with ARM profiler. Then the decoder system is partitioned into software part and hardware part respectively based on the property of analysis. The software part is developed for the implementation of intensive decision making operations needed for audio bitstreams. The hardware part is a dedicated hardware for the regular and computation-intensive operations in multi-standard audio decoding. Here is focused on the implementation of OpenRISC 1200 (OR1200) CPU and the profiler of ARM is only for analyzing and profiling
