Browsing by Subject "MPEG (Video coding standard)"

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    BilVideo-7 : video parsing, indexing and retrieval
    (2010) Baştan, Muhammet
    Video indexing and retrieval aims to provide fast, natural and intuitive access to large video collections. This is getting more and more important as the amount of video data increases at a stunning rate. This thesis introduces the BilVideo-7 system to address the issues related to video parsing, indexing and retrieval. BilVideo-7 is a distributed and MPEG-7 compatible video indexing and retrieval system that supports complex multimodal queries in a unified framework. The video data model is based on an MPEG-7 profile which is designed to represent the videos by decomposing them into Shots, Keyframes, Still Regions and Moving Regions. The MPEG-7 compatible XML representations of videos according to this profile are obtained by the MPEG-7 compatible video feature extraction and annotation tool of BilVideo-7, and stored in a native XML database. Users can formulate text, color, texture, shape, location, motion and spatio-temporal queries on an intuitive, easy-touse visual query interface, whose composite query interface can be used to formulate very complex queries containing any type and number of video segments with their descriptors and specifying the spatio-temporal relations between them. The multithreaded query processing server parses incoming queries into subqueries and executes each subquery in a separate thread. Then, it fuses subquery results in a bottom-up manner to obtain the final query result and sends the result to the originating client. The whole system is unique in that it provides very powerful querying capabilities with a wide range of descriptors and multimodal query processing in an MPEG-7 compatible interoperable environment.
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    Query processing for an MPEG-7 compliant video database
    (2008) Çam, Hayati
    Based on the recent advancements in multimedia, communication, and storage technologies, the amount of audio-visual content stored is increased dramatically. The need to organize and access the growing multimedia content led researchers to develop multimedia database management systems. However, each system has its own way of describing the multimedia content that disables interoperability among other systems. To overcome this problem and to be able to standardize the description of audio-visual content stored in those databases, MPEG-7 standard has been developed by MPEG (Moving Picture Experts Group). In this thesis, a query language and a query processor for an MPEG-7 compliant video database system is proposed. The query processor consists of three main modules: query parsing module, query execution module, and result fusion module. The query parsing module parses the XML based query and divides it into subqueries. Each sub-query is then executed with related query execution module and the final result is obtained by fusing the results of the sub-queries according to user defined weights. The prototype video database system BilVideo v2.0, which is formed as a result of this thesis work, supports spatio-temporal and low level feature queries that contain any weighted combination of keyword, temporal, spatial, trajectory, and low level visual feature (color, shape and texture) queries. Compatibility with MPEG-7, low-level visual query support, and weighted result fusion feature are the major factors that highly differentiate between BilVideo v2.0 and its predecessor, BilVideo.
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    Three-dimensional video coding on mobile platforms
    (2009) Bal, Can
    With the evolution of the wireless communication technologies and the multimedia capabilities of the mobile phones, it is expected that three-dimensional (3D) video technologies will soon get adapted to the mobile phones. This raises the problem of choosing the best 3D video representation and the most efficient coding method for the selected representation for mobile platforms. Since the latest 2D video coding standard, H.264/MPEG-4 AVC, provides better coding efficiency over its predecessors, coding methods of the most common 3D video representations are based on this standard. Among the most common 3D video representations, there are multi-view video, video plus depth, multi-view video plus depth and layered depth video. For using on mobile platforms, we selected the conventional stereo video (CSV), which is a special case of multi-view video, since it is the simplest among the available representations. To determine the best coding method for CSV, we compared the simulcast coding, multi-view coding (MVC) and mixed-resolution stereoscopic coding (MRSC) without inter-view prediction, with subjective tests using simple coding schemes. From these tests, MVC is found to provide the best visual quality for the testbed we used, but MRSC without inter-view prediction still came out to be promising for some of the test sequences and especially for low bit rates. Then we adapted the Joint Video Team’s reference multi-view decoder to run on ZOOMTM OMAP34xTM Mobile Development Kit (MDK). The first decoding performance tests on the MDK resulted with around four stereo frames per second with frame resolutions of 640×352. To further improve the performance, the decoder software is profiled and the most demanding algorithms are ported to run on the embedded DSP core. Tests resulted with performance gains ranging from 25% to 60% on the DSP core. However, due to the design of the hardware platform and the structure of the reference decoder, the time spent for the communication link between the main processing unit and the DSP core is found to be high, leaving the performance gains insignificant. For this reason, it is concluded that the reference decoder should be restructured to use this communication link as infrequently as possible in order to achieve overall performance gains by using the DSP core.