For outstanding coding efficiency with scalability functions, SVC (Scalable Video Coding) is being standardized.
SVC can support spatial, temporal and SNR scalability and these scalabilities are useful to provide a smooth video
streaming service even in a time varying network such as a mobile environment. But current SVC is insufficient to
support dynamic video conversion with scalability, thereby the adaptation of bitrate to meet a fluctuating network
condition is limited. In this paper, we propose dynamic full-scalability conversion methods for QoS adaptive video
streaming in SVC. To accomplish full scalability dynamic conversion, we develop corresponding bitstream extraction,
encoding and decoding schemes. At the encoder, we insert the IDR NAL periodically to solve the problems of spatial
scalability conversion. At the extractor, we analyze the SVC bitstream to get the information which enable dynamic
extraction. Real time extraction is achieved by using this information. Finally, we develop the decoder so that it can
manage the changing scalability. Experimental results showed that dynamic full-scalability conversion was verified and
it was necessary for time varying network condition.
In this paper, we propose a new functionality to Scalable Video Coding, which is the support of multiple ROIs. SVC is targeted at the flexible extraction of some bitstream from the original SVC bitstream, and it is discussed in the MPEG committee for standardization. Region of interest (ROI) is an area that is semantically important to a particular user. It is expected that a bitstream that contains the ROI can be extracted without any transcoding operations. In many cases, the user may want to see more than one ROIs at the same time. The existence of multiple ROIs results in some difficulties in extracting the bitstream containing more than one ROI. In this paper, we present solutions to address these difficulties.
In scalable video coding (SVC), video quality can be controlled by bit-stream extraction. The bit-stream extraction is to extract network abstraction layer (NAL) units for the required quality. Since scalable bit-stream is packed in NAL units, quality control of SVC video is highly related to NAL unit extraction policy at a given bit-rate. Therefore, effective extraction policy is required to provide SVC video with optimal quality. In this paper, a SVC bit-stream extraction method based on perceptual quality is proposed. The main goal of this work is to find the optimal extraction policy for SVC bit-stream that contain the spatial, temporal, and SNR scalability at a given bit-rate. Also, to consider perceptual quality relied on video characteristics, the video segments are classified into different classes, namely action, crowd, dialog, scenery, and text&graphic. As a result of a subjective test on the classified video scenes, consistent characteristic of perceptual quality preference is achieved. Based on this, quality information table (QIT) has been determined for each class which guides the bit-stream extraction process. The determined QIT is applied to SVC bit-stream extraction depending on to which class a video segment belongs. In the experiment, the proposed extraction scheme is applied for SVC bit-stream extraction belongs to action class. Extraction policy to maximize perceptual quality of action class is applied based on QIT for action class. The extracted video and multi-dimensional scalability resulted from the proposed scheme are also described.
Quality is an essential factor in multimedia communication, especially in compression and adaptation. Quality metrics can be divided into three categories: within-modality quality, cross-modality quality, and multi-modality quality. Most research has so far focused on within-modality quality. Moreover, quality is normally just considered from the perceptual perspective. In practice, content may be drastically adapted, even converted to another modality. In this case, we should consider the quality from semantic perspective as well. In this work, we investigate the multi-modality quality from the semantic perspective. To model the semantic quality, we apply the concept of "conceptual graph", which consists of semantic nodes and relations between the nodes. As an typical of multi-modality example, we focus on audiovisual streaming service. Specifically, we evaluate the amount of information conveyed by a audiovisual content where both video and audio channels may be strongly degraded, even audio are converted to text. In the experiments, we also consider the perceptual quality model of audiovisual content, so as to see the difference with semantic quality model.
In heterogeneous computing environments, multimedia contents would be adapted drastically in terms of quality as well as modality. There is a strong need to measure the content quality in this context, i.e. with both content scaling and modality conversion. However, the quality is often considered within a single modality (e.g. video, audio). There has been very little work on quality evaluation when the content's modality is variously converted (e.g. a video converted to a sequence of "important" images or explanatory text). This paper aims at evaluating the content quality across different scaling levels and modalities. We contend that the quality consists of two key aspects: the perceptual quality and the semantic quality. The former refers to user's satisfaction in perceiving the content, regardless of what information the content contains; the latter, which is crucial in modality conversion, refers to the amount of conveyed information, regardless of how the content is presented. We design a procedure to measure these two qualities through subjective tests, and then we present computational methods that can be used to replace the time-consuming subjective method. The experiments show the insights into the dependence of the qualities on modalities and content scaling levels.
KEYWORDS: Visualization, Color vision, Cones, Multimedia, Eye, Visual process modeling, RGB color model, Information visualization, Image enhancement, Color blindness
In this paper, we propose content adaptation for visual impairments in MPEG-21. The proposed content adaptation aims
to give enhanced visual accessibility to users with visual impairment in MPEG-21. In this paper, we consider two major
visual impairments: low vision impairment and color vision deficiency. The proposed method includes description for
the visual impairments and content adaptation technique based on it. We have developed a symptom-based description
of visual impairment characteristics for users with visual impairment in the context of MPEG-21 digital item adaptation
(DIA). To verify usefulness of the proposed method, we performed some experiments with the content adaptation based
on the description in MPEG-21. The experiment results showed that the proposed method is effective content adaptation
for user with visual impairment and gives enhanced visual accessibility to them.
In this paper we propose an automated abstract extraction for soccer video using MPEG-7 descriptors. The video abstraction is created in form of highlight scenes which represent some pre-defined contexts. For soccer video, the events often have some specific order of actions, so the Hidden Markov Models (HMMs) are employed to detect the interested highlights. In our system, the input video is first separated into shots, then the video shots are classified and clustered based on the features of MPEG-7 standard descriptors. The HMM-based detection has two layers. The first is to eliminate the trivial scenes, and the second is to distinguish the highlights of different semantic events. Specific user preference will be used to select the highlight scenes relevant to the interest of user.
Traffic specification plays a crucial role in resource reservation for multimedia services over packet networks. The current development of QoS-guaranteed services still leaves a wide room for the selection of traffic specification. In this paper, we propose a new method to estimate the traffic specification of deterministic service. Usually, the estimation of traffic specification is independent of the QoS requirements, e.g. the delay bound. The proposed method is based on the point-of-view of the call admission control that takes the delay bound requirement into the estimation process. The solution is efficient in the sense that the resulting traffic specification is simple while still providing the excellent network utilization. Additionally, traffic smoothing is now a popular technique used to flatten the bursty video traffic, so reducing the potential congestion in the networks. We consider the traffic specification of video traffic in two cases: with traffic smoothing and without traffic smoothing. Initial experiments show that traffic smoothing does not result in significant changes in values of traffic specification. This highlights the importance of global burstiness of video traffic to the traffic parameters. The results of this research can be directly applied to some existing applications such as the integrated services of ATM and IETF.
KEYWORDS: Video, Internet, Receivers, Prototyping, Local area networks, Multimedia, Video processing, Network architectures, Communication engineering, Signal to noise ratio
MPEG streaming over Mobile Internet leads to degradation of MPEG video quality. When a handoff of a mobile node (MN) occurs, it is quite difficult to guarantee seamless video quality due to the change of routing path towards the MN. In this paper, we propose a new scheme, MPEG streaming over Concatenation and Optimization for Reservation Path (CORP), to guarantee QoS of MPEG streaming service in the Mobile Internet. When a handoff of a MN occurs, the CORP extends the existing reservation path, which was established using RSVP between a server and a MN, to a new Base Station (BS) that the MN currently connected to, instead of making a new RSVP session between the server and the MN. To demonstrate practicality of the proposed scheme, we built a prototype system which provides the MPEG-1 Video and Audio on demand over Mobile Internet using Mobile IP and IEEE 802.11b wireless LAN. Our experiment shows that the proposed scheme significantly improves the peak signal-to-noise rate (PSNR) of MPEG streaming video. Also, we analyzed the video quality of our scheme with respect to TCP and UDP transport protocols.
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