多媒體資料庫中連續媒體資料的儲存管理之設計與分析

Abstract

多媒體資料乃是包含文字，影像，動畫，聲音與視訊等各式的集合。而多 媒體資料庫管理系統則是來管理這些多媒體資料。為了提昇資料擷取的效 能，設計良好的儲存結構將是必須的。其設計的重點包括:資料儲存放置 策略以及相關播放動作的建立。"連續性媒體"，例如:視訊，需要很大的 頻寬與儲存空間且只有在它被及時地播放時，其蘊含的資訊才有意義。所 以，針對連續性媒體，如何提供連續擷取，隨機存取與互動瀏覽，將是極 大的挑戰。首先﹐我們提出一種無需重組資料的"碰撞解除"法以保證資料 連續擷取的特性。進而﹐為降低資料搬動成本﹐我們改良此法並提出兩 種"延遲"法: 一為"先解決碰撞"法﹐一為"後解決碰撞"法。其次﹐我們提 出一種無需額外資源的"多重取樣"策略以提供隨選視訊系統互動式瀏覽的 需求﹐此法乃是延伸"段落取樣"策略以提供多重物件以不同的速度播放。 再則﹐對一個互動式播放的應用﹐系統必須提供使用者隨時隨意地選擇播 放的內容﹐即使是系統正在播放中。對此﹐我們提出一種僅需記錄少許擷 取資訊的"滑動視窗"法。進而﹐為提供線上互動式播放﹐我們提出了"動 態滑動視窗"法。最後﹐對一些應用﹐諸如: "自我學習"系統﹐使用者可 能快速地瀏覽其所熟悉的部份而緩慢地學習其所不熟的部份。在如此的系 統中﹐所有的資料都是重要且不能被漏失的。因此﹐我們提出一種有效率 的方法以支援此種動態需求頻寬的狀況。 A multimedia database management system manages multimedia data, where multimedia data is defined as any combination of data in the form of text, image, animation, sound and video. To improve the performance for efficient dataaccess in a multimedia database system, the design of a multimedia storage server, including storage placement strategies and the implementation of related operations, is required. A continuous media, like video, requires high bandwidth and large storage space and conveys meaning only when presented in time. Therefore, how to support continuous retrieval, random access and interactive browsing of multimedia data at its required bandwidth is a challenging task. First, to guarantee the property of continuous retrieval, we propose a conflict-resolution approach to supporting random access without reorganization of the whole data. Moreover, a deferring approach is proposed to reduce those additional movement cost at the cost of an additional buffer. Based on this approach, we develop two strategies: the conflict-resolved- first-deferring approach and the conflict-resolved-last- deferring strategy. Second, to support interactive browsing functions such as the fast forward function in a Video-On- Demand system, we propose a multi-sampling strategy, which generalizes the approach of the segment-sampling strategy to support continuous display of multiple objects at different display speed rates, simultaneously, without any additional resources. Third, for an interactive display application, a system must support users to make any choice of objects for display even when display has started. To achieve this goal, we propose a sliding window approach to supporting interactive display for continuous media, in which we only record a little necessary information of retrieval of the following subobjects for display in a sliding window. To further support on-line interactive display, in which the combination of objects for display and the branch points for choices are dynamically determined, we extend the sliding window approach to the dynamic sliding approach. Finally, for some applications, such as self- learning system, users may quickly browse some familiar objects while they will slowing scan some unfamiliar objects. To completely support such a learning system, no subobjects of the objects can be omitted and the required bandwidth of each object must be dynamically increased or decreased depending on the user's requirement. Therefore, we propose an efficient approach to supporting continuous retrieval with dynamic required bandwidths without reorganizing the whole striped object.