- 學位論文
DVB-H IP解封裝器設計與實現
Design and Implementation of a DVB-H IP-Decapsulator
摘要
自歐洲電信標準組織制定DVB-H規範後，數位電視即邁入手持式應用的領域。DVB-H標準以DVB-T為基礎，更加以制定編碼正交分頻多工、時間切片與多協定封裝前向錯誤更正機制，並相容於現有的DVB-T廣播標準。 本論文主旨為設計具時間切片與解多協定封裝機制的DVB-H IP解封裝器，並以軟體的方式實現具備跨平台、高度適應性與高度擴充性的IP解封裝模組。在手持式裝置的應用中，能源消耗的問題一直是手持裝置的設計重點，時間切片的機制能有效減低能源消耗最為嚴重的DVB-H解調器耗電問題，能源節省的效能達到90%，省電效果依據電視台所送出的時間切片而異。DVB-H協定倚重多協定封裝的傳輸方式，不同於DVB組織的其他協定，DVB-H的影音資料不再是直接封裝於MPEG-2傳輸串流中，而是採用IP廣播封包封裝影像串流後，再經多協定封裝後載送於MPEG-2傳輸串流中，以達到向下相容於DVB-T的目的。 本研究以純Java語言實現DVB-H解碼機制，以實現跨平台能力。並制定平台適配層減低Java虛擬機器與解調器硬體之間的驅動複雜度。DVB-H IP解封裝器中設置傳輸串流分派模組，讓DVB-H傳輸串流中的資訊表單解碼模組各自獨立，解碼模組僅需向傳輸串流分派器註冊特定的傳輸封包資訊後，便能從傳輸串流分派器中取得該解碼器所支援的封包，以利於未來規範中新增資訊表單時，能夠以現有的資源擴充新的解碼模組。
並列摘要
Since the European Telecommunications Standard Institute standardizes the DVB-H standard, the digital TV intrudes into the applications of handheld devices. The fundamental of DVB-H standard is based on DVB-T and additionally incorporates with the techniques of Coded Orthogonal Frequency Division Multiplexing, Time-slicing and Multi-Protocol Encapsulation-Forward Error Correction for compatible with the existing broadcasting standard. The main subject of this thesis is to design a DVB-H IP-Decapsulator which can achieve the operation of Time-slicing and Multi-Protocol Encapsulation. The proposed DVB-H IP-Decapsulator can provide the capability of platform cross, high adaptation and high adaptability through the software implementation manner. In the applications of the handheld device, the problem of power consumption is always a design issue. The mechanism of time-slicing can effectively reduce the most serious power consumption problem of DVB-H demodulator. Although the official specification has pointed out that it can achieve 90% power consumption saving, but the real power consumption saving extremely depends on the time-slice transmitted from the television station. The DVB-H protocol uses the MPE to deliver the information. Differ from the other protocols of the DVB organizations, the video and sound data of the DVB-H are not packed into the MPEG-2 transport stream directly, they are firstly packed into the IP datagram followed by Multi-Protocol Encapsulation, and finally delivered via the MPEG-2 transport stream. Consequently, the purpose of the backward compatible with the DVB-T can be achieved. This research implements the mechanism of the DVB-H IP-Decapsulation by using the pure Java language to aim at the ability of platform across. We specific a Platform Adaptive Layer to reduce the driving complexity between Java virtual machine and the demodulator. Since the DVB-H has built-in an IP-Dencaplator Transport Stream Dispatcher module, it makes the sub decoders of Program Specific Information/Service Information independently. Therefore, the identification of the packet which recognized by the sub decoders can be obtained from the Transport Stream Dispatcher while the registration for specific packet was completed. Via the above mechanism, the new decoding module can be expended through the existing resources in case of the additional information tables are included in the future.