| 1. |
- Devlic, Alisa, et al.
(author)
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Energy consumption reduction via context-aware mobile video pre-fetching
- 2012
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In: Proceedings - 2012 IEEE International Symposium on Multimedia, ISM 2012. - : IEEE. - 9780769548753 ; , s. 261-265
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Conference paper (peer-reviewed)abstract
- The arrival of smartphones and tablets, along with a flat rate mobile Internet pricing model have caused increasing adoption of mobile data services. According to recent studies, video has been the main driver of mobile data consumption, having a higher growth rate than any other mobile application. However, streaming a medium/high quality video files can be an issue in a mobile environment where available capacity needs to be shared among a large number of users. Additionally, the energy consumption in mobile devices increases proportionally with the duration of data transfers, which depend on the download data rates achievable by the device. In this respect, adoption of opportunistic content pre-fetching schemes that exploit times and locations with high data rates to deliver content before a user requests it, has the potential to reduce the energy consumption associated with content delivery and improve the user's quality of experience, by allowing playback of pre-stored content with virtually no perceived interruptions or delays. This paper presents a family of opportunistic content pre-fetching schemes and compares their performance to standard on-demand access to content. By adopting a simulation approach on experimental data, collected with monitoring software installed in mobile terminals, we show that content pre-fetching can reduce energy consumption of the mobile devices by up to 30% when compared to the on demand download of the same file, with a time window of 1 hour needed to complete the content prepositioning.
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| 2. |
- Li, Haopeng, et al.
(author)
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3D model hypotheses for player segmentation and rendering in free-viewpoint soccer video
- 2012
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In: Proceedings - 2012 IEEE International Symposium on Multimedia, ISM 2012. - : IEEE. - 9780769548753 ; , s. 203-209
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Conference paper (peer-reviewed)abstract
- This paper presents a player segmentation approach based on 3D model hypotheses for soccer games. We use a hyperplane model for player modeling and a collection of piecewise geometric models for background modeling. To determine the assignment of each pixel in the image plane, we test it with two model hypotheses. We construct a cost function that measures the fitness of model hypotheses for each pixel. To fully utilize the perspective diversity of the multiview imagery, we propose a three-step strategy to choose the best model for each pixel. The experimental results show that our segmentation approach based on 3D model hypotheses outperforms conventional temporal median and graph cut methods for both subjective and objective evaluation.
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| 3. |
- Lu, Xiaohua, et al.
(author)
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H.264-compatible coding of background soccer video using temporal subbands
- 2012
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In: Proceedings - 2012 IEEE International Symposium on Multimedia, ISM 2012. - : IEEE. - 9780769548753 ; , s. 141-144
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Conference paper (peer-reviewed)abstract
- This paper presents an H.264-compatible temporal subband coding scheme for static background scenes of soccer video. We utilize orthonormal wavelet transforms to decompose a group of successive frames into temporal subbands. By exploiting the property of energy conservation of orthonormal wavelet transforms, we construct a rate distortion model for optimal bitrate allocation among different subbands. To take advantage of the high efficiency video codec H.264/AVC, we encode each subband with H.264/AVC Fidelity Range Extension (FRExt) intra-coding by assigning optimal bitrates. The experimental results show that our proposed coding scheme outperforms conventional video coding with H.264/AVC for both subjective and objective evaluations.
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| 4. |
- Rana, Pravin Kumar, 1982-, et al.
(author)
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A Variational Bayesian Inference Framework for Multiview Depth Image Enhancement
- 2012
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In: Proceedings - 2012 IEEE International Symposium on Multimedia, ISM 2012. - : IEEE. - 9780769548753 ; , s. 183-190
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Conference paper (peer-reviewed)abstract
- In this paper, a general model-based framework for multiview depth image enhancement is proposed. Depth imagery plays a pivotal role in emerging free-viewpoint television. This technology requires high quality virtual view synthesis to enable viewers to move freely in a dynamic real world scene. Depth imagery of different viewpoints is used to synthesize an arbitrary number of novel views. Usually, the depth imagery is estimated individually by stereo-matching algorithms and, hence, shows lack of inter-view consistency. This inconsistency affects the quality of view synthesis negatively. This paper enhances the inter-view consistency of multiview depth imagery by using a variational Bayesian inference framework. First, our approach classifies the color information in the multiview color imagery. Second, using the resulting color clusters, we classify the corresponding depth values in the multiview depth imagery. Each clustered depth image is subject to further subclustering. Finally, the resulting mean of the sub-clusters is used to enhance the depth imagery at multiple viewpoints. Experiments show that our approach improves the quality of virtual views by up to 0.25 dB.
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