A number of automated shot-change detection methods for indexing a video sequence to facilitate browsing and retrieval have been proposed. Many of these methods use color histograms or features computed from block motion or compression parameters to compute frame differences. It is important to evaluate and characterize their performance so as to deliver a single set of algorithms that may be used by other researchers for indexing video databases. We present the results of a performance evaluation and characterization of a number of shot-change detection methods that use color histograms, block motion matching, or MPEG compressed data.

Performance characterization of video-shot-change detection methods

A survey on the use of pattern recognition methods for abstraction, indexing and retrieval of images and video

Signatures from MPEG or Motion JPEG encoded video clips are extracted based on the luminance, chrominance, and motion vector values. The signatures are stored in a database, along with corresponding location, size, and time length information. The signature of a query video clip, also encoded in the MPEG or Motion JPEG format, is extracted. The signature of the query video clip is comparred with the signatures stored in the meta database, with video clips having signatures similar to the signature of the query video clip identified. The video clips are then retrieved and displayed by selection of a user.

Video retrieval of MPEG compressed sequences using DC and motion signatures

Object-based video representation, such as the one suggested by the MPEG-4 standard, offers a framework that is better suited for object-based video indexing and retrieval. In such a framework, the concept of a "key frame" is replaced by that of a "key video object plane". In this paper, we propose a method for key video object plane selection using the shape information in the MPEG-4 compressed domain. The shape of the video object (VO) is approximated using the shape coding modes of I, P, and B video object planes (VOPs) without decoding the shape information in the MPEG-4 bit stream. Two popular shape distance measures, the Hamming and Hausdorff distance measures, are modified to measure the similarities between the approximated shapes of the video objects. Although they feature different computational and implementation complexity tradeoffs, the corresponding algorithms achieve essentially the same performance levels in selecting key video object planes that represent efficiently the salient content of the video objects.

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Automatic key video object plane selection using the shape information in the MPEG-4 compressed domain

Adaptive streaming over Hyper-Text Transport protocol (HTTP) is the new trend in video delivery on the Internet and is expected to be supported by consumer electronic devices such as Blu-ray players and DVRs. Proprietary solutions have been around for a couple of years and standardization efforts are entering the final stage. In order to make this platform successful, optimized content preparation algorithms are needed. We propose a contentbased segmentation process for adaptive streaming over HTTP. This solution offers a good balance between network delivery requirements and rate-distortion (RD) performance. Resulting video stream is tailored for better quality of experience (QoE) for the end user. Experiments confirm that our algorithm outperforms popular segmentation techniques and saves10% of bandwidth on average for the same objective quality levels. This saving is significant given the volume of traffic that video delivery generates every day on the Internet.

Optimizing video encoding for adaptive streaming over HTTP

Video is an important and challenging medium and requires sophisticated indexing schemes for efficient retrieval from visual databases. An important step in video indexing is scene change detection. Recently, several scene change detection algorithms in the pixel and compressed (MPEG-2) domains have been reported in the literature. These algorithms are computationally complex and are not very robust in detecting gradual scene changes. The authors propose an efficient technique for detecting scene changes in the MPEG-2 compressed domain. The proposed algorithm has the advantage of fast scene change detection. In addition, this algorithm has the potential to detect gradual scene changes.

J. Wei

Papers

A scene change detection algorithm for MPEG compressed video sequences