In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that...In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the 'moov' box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Re1-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.展开更多
National and international publishers have been depositing digital publications at the National Library of the Netherlands (KB) since 2003. Until recently, most of these publications were deposited in the Portable Doc...National and international publishers have been depositing digital publications at the National Library of the Netherlands (KB) since 2003. Until recently, most of these publications were deposited in the Portable Document Format. New projects, for example the Web archiving project, force the KB to handle more heterogeneous material. Therefore, the KB has developed a quantifiable file format risk assessment method. This method can be used to define digital preservation strategies for specific file formats. The choice for a specific file format at creation time or later in the life cycle of a digital object influences the long-term access to the digital object. The evaluation method contains seven sustainability criteria for file formats that are weighed for importance. There seems to be consensus on the sustainability criteria. However, as the weighing of these criteria is connected to an institution's policy, the KB wonders whether agreement on the relative importance of the criteria can be reached at all. With this paper, the KB hopes to inspire other cultural heritage institutions to define their own quantifiable file format evaluation method.展开更多
A file format for storage of scalable video is proposed. A generic model is presented to enable a codec independent description of scalable video stream. The relationships, especially the dependencies, among sub-strea...A file format for storage of scalable video is proposed. A generic model is presented to enable a codec independent description of scalable video stream. The relationships, especially the dependencies, among sub-streams in a scalable video stream are specified sufficiently and effectively in the proposed model. Complying with the presented scalable video stream model, the file format for scalable video is proposed based on ISO Base Media File Format, which is simple and flexible enough to address the demands of scalable video application as well as the non-scalable ones.展开更多
本文设计了一种专用的图形文件格式(CPF:Pattern format for CETC48),旨在优化电子束光刻设备中的图形数据存储与传输。详细阐述了CPF文件格式的文件结构、数据组成及所采用的多种图形压缩算法。实验结果表明,CPF格式在文件存储效率及...本文设计了一种专用的图形文件格式(CPF:Pattern format for CETC48),旨在优化电子束光刻设备中的图形数据存储与传输。详细阐述了CPF文件格式的文件结构、数据组成及所采用的多种图形压缩算法。实验结果表明,CPF格式在文件存储效率及处理性能上均优于现有格式,该格式已通过了实验证,满足了设计要求及电子束光刻设备的需求。展开更多
目的嵌入式数字视频录像机(digital video recorder,DVR)系统中的多媒体(视频/音频)数据往往是电子数据司法鉴定领域的重要证据,然而在司法鉴定实践中,DVR被意外删除、恶意删除或遭受损坏导致DVR中数据无法访问的现象屡见不鲜,这无疑使...目的嵌入式数字视频录像机(digital video recorder,DVR)系统中的多媒体(视频/音频)数据往往是电子数据司法鉴定领域的重要证据,然而在司法鉴定实践中,DVR被意外删除、恶意删除或遭受损坏导致DVR中数据无法访问的现象屡见不鲜,这无疑使得电子数据鉴定过程变得更加困难。方法结合司法鉴定工作实务,主要以存储于Micro SD卡中无法访问的DVR视频文件为例,开展了基于文件分配表(file allocation table,FAT)32文件系统和H.264相关文件格式的DVR数据恢复研究。结果通过探讨的两种方法恢复的视频文件可以正常访问,同时还可通过运行脚本文件实现DBR的自动重建。结论探讨的两种方法可有效恢复FAT32文件系统的DVR数据和H.264格式的DVR数据。此外,通过运行脚本文件自动重构DBR,可有效提高司法鉴定效率。相关鉴定技术的研究对嵌入式DVR视频的鉴定技术研究具有重要的理论研究意义和实践应用价值。展开更多
文摘In this paper we describe how progressive download and adaptive streaming can be combined into a simple and efficient streaming framework. Based on the MPEG-4 file format (MP4) we use HTTP for transport and argue that these two components are sufficient for specifying an open streaming architecture. The client selects appropriate chunks from the MP4 file to be transferred based on (1) the header information (i.e. the 'moov' box) in the first part of the file and (2) his observation of network throughput. The framework is completely client driven which allows for better server scalability and reduces signalling overhead. We discuss architecture and implementation issues such as complexity, interoperability and scalability and compare to 3GPP PSS Re1-6 adaptive streaming when appropriate. Measurements from a simple MP4/HTTP streaming client are presented showing that appropriate chunks are selected such that increased reliability is achieved.
文摘National and international publishers have been depositing digital publications at the National Library of the Netherlands (KB) since 2003. Until recently, most of these publications were deposited in the Portable Document Format. New projects, for example the Web archiving project, force the KB to handle more heterogeneous material. Therefore, the KB has developed a quantifiable file format risk assessment method. This method can be used to define digital preservation strategies for specific file formats. The choice for a specific file format at creation time or later in the life cycle of a digital object influences the long-term access to the digital object. The evaluation method contains seven sustainability criteria for file formats that are weighed for importance. There seems to be consensus on the sustainability criteria. However, as the weighing of these criteria is connected to an institution's policy, the KB wonders whether agreement on the relative importance of the criteria can be reached at all. With this paper, the KB hopes to inspire other cultural heritage institutions to define their own quantifiable file format evaluation method.
基金Project supported by the National Natural Science Foundation of China (No. 60572104) and the Natural Science Foundation (No. 40410031) of Beijing, China.
文摘A file format for storage of scalable video is proposed. A generic model is presented to enable a codec independent description of scalable video stream. The relationships, especially the dependencies, among sub-streams in a scalable video stream are specified sufficiently and effectively in the proposed model. Complying with the presented scalable video stream model, the file format for scalable video is proposed based on ISO Base Media File Format, which is simple and flexible enough to address the demands of scalable video application as well as the non-scalable ones.
文摘本文设计了一种专用的图形文件格式(CPF:Pattern format for CETC48),旨在优化电子束光刻设备中的图形数据存储与传输。详细阐述了CPF文件格式的文件结构、数据组成及所采用的多种图形压缩算法。实验结果表明,CPF格式在文件存储效率及处理性能上均优于现有格式,该格式已通过了实验证,满足了设计要求及电子束光刻设备的需求。
