An important issue in the performance of Video Streaming systems is the data transmission mechanism used by the server. Streaming servers can use a variety of techniques, which have an impact on a number of metrics as...
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ISBN:
(纸本)9781467362399
An important issue in the performance of Video Streaming systems is the data transmission mechanism used by the server. Streaming servers can use a variety of techniques, which have an impact on a number of metrics associated with the performance and the quality of the video presentation. One of the related issues is the assignment of buffer space at the client in order to hold data that has arrived earlier than their playback time. In this article, we conduct a number of experiments with MPEG-4 compressed video, in order to obtain buffering occupancy values for various transmission mechanisms. In particular, we consider some of the mechanisms used by YouTube video servers, and contrast their performance with that of other mechanisms.
This paper presents a comparison of original couplings between color filter array demosaicking methods and wavelet compression (JPEG2000). We focus on an application handling huge microscopy images (64 K/spl times/64 ...
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This paper presents a comparison of original couplings between color filter array demosaicking methods and wavelet compression (JPEG2000). We focus on an application handling huge microscopy images (64 K/spl times/64 K pixels) for telediagnosis. Whereas coding is usually achieved after interpolation, we also consider demosaicking after decompression in order to optimize image quality for a given size of data. We also study the JPEG2000 stream structure for interactive visualization.
Due to the ubiquitous nature of the Internet, it is being targeted to support video applications, such as video-on-demand (VOD). However, with the growing popularity of the Internet, congestion in the network poses a ...
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Due to the ubiquitous nature of the Internet, it is being targeted to support video applications, such as video-on-demand (VOD). However, with the growing popularity of the Internet, congestion in the network poses a great hurdle in transferring real-time video data. For pre-compressed MPEG-2 video streams, the network may not be able to maintain acceptable level of quality of service (QoS) if there are insufficient resources available during the life of the connection. In such situations, we can use rate control to reduce the bit rate of the video according to the available resources. In this paper we propose a scaleable delivery mechanism for pre-compressed VBR MPEG-2 video streams, where the traffic rate is adapted according to the network congestion status. Using this scheme, a reasonable level of QoS is maintained when the network is congested. Based on the scheme a prototype system has been developed which demonstrates the usefulness of the scheme.
Our proposed Level Adaptive Overdrive Technology, that has improved gray-level response of LCDs, has been reviewed. We also introduced a recently developed advanced level-adaptive overdrive (ALAO) method applicable to...
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ISBN:
(纸本)9781509065530
Our proposed Level Adaptive Overdrive Technology, that has improved gray-level response of LCDs, has been reviewed. We also introduced a recently developed advanced level-adaptive overdrive (ALAO) method applicable to full-digital HD-LCTVs, which not only reduced the gray level response time to less than one fourth, but also improved S/N for still pictures by 10 dB and reduced the circuit cost for LAO method to almost half that of a conventional LAO circuit. We applied the ALAO method to a full-HDLC projector with 1.84 M pixels and obtained high full-HD motion picture qualities. In addition, we introduced the most recently developed software-processed level-adaptive overdrive (SLAO) method without any additional hardware and cost-up.
This paper presents some arguments in favour of further research in video compression because of scarce spectrum resources for mobile applications and the lack of powerful tools for scalable coding. Finally some ideas...
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This paper presents some arguments in favour of further research in video compression because of scarce spectrum resources for mobile applications and the lack of powerful tools for scalable coding. Finally some ideas and results for metadata based compression, improved prediction and scalable schemes are presented.
For the digital transmission of TV the video-signal will be highly compressed with the MPEG-2 source coding algorithm. The MPEG-2 source coded stream is very sensitive to channel disturbances due to variable length co...
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For the digital transmission of TV the video-signal will be highly compressed with the MPEG-2 source coding algorithm. The MPEG-2 source coded stream is very sensitive to channel disturbances due to variable length coding. A single bit error may result in error propagation, therefore, it will cause a high degradation of picture quality. Hence, error concealment techniques or iterative decoding techniques might be required at the receiver. The aim of this article is to study different techniques for handling channel errors at the receiver side. The first way is to apply error concealment techniques after source decoding. For P- and B-pictures, the inherent motion vectors can be used for temporal error concealment (TEC) which yields very good results. However, in I-pictures no motion vectors exist for TEC. Furthermore, the spatial error concealment (SEC) techniques suffer from the non existence of neighbored macroblocks (MBs) because of the re-synchronization at the slice level. Therefore, another technique, which is called early re-synchronization, in combination with an enhanced error detection technique is investigated in this article. With this technique most of the correct received data can be exploited for error concealment and the quality of service mainly in I-pictures will be improved. A second way for handling channel errors is to apply iterative channel decoding. With this, the error correction capability of the channel decoding part can be improved and less residual errors will occur in the bitstream.
This paper presents a robust method to detect scene changes from compressed video streams. Scene changes are detected with DC components of DCT coefficients in MPEG encoded video sequences. Instead of decoding full fr...
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ISBN:
(纸本)0780355830
This paper presents a robust method to detect scene changes from compressed video streams. Scene changes are detected with DC components of DCT coefficients in MPEG encoded video sequences. Instead of decoding full frames, partial macroblocks of each frame, horizontal and vertical macroblocks, are decoded to perform scene changes. This method detects abrupt and gradual scene changes by decoding minimal blocks and saves a lot of computations. The experiment results show at least 95% detection performance for dramas, news and animations.
In this paper, A wireless video monitoring system based on GPRS network and ARM9 is designed. The embedded chip and the programming techniques are adopted. The central monitor which adopts S3C2416 chip as controller i...
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In this paper, A wireless video monitoring system based on GPRS network and ARM9 is designed. The embedded chip and the programming techniques are adopted. The central monitor which adopts S3C2416 chip as controller is the core of the whole system. First, USB camera video data are collected by the embedded Linux system, processed, compressed and transferred by the processing chip. Then, video data are sent to the monitor client by GRPS network. Tests show the presented wireless video surveillance system is reliable and stable. And it has a perfect application prospects with real-time monitor.
MPEG-4 supports coding of video objects with spatial and temporal scalability. Scalability allows decoding a part of a stream and construct images with reduced decoder complexity (reduced quality)
MPEG-4 supports coding of video objects with spatial and temporal scalability. Scalability allows decoding a part of a stream and construct images with reduced decoder complexity (reduced quality)
An original algorithm for the approximation of the discrete cosine transform (DCT) without multiplication is presented. The method is based on a recursive generator of discrete harmonic signals. The "speed/accura...
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An original algorithm for the approximation of the discrete cosine transform (DCT) without multiplication is presented. The method is based on a recursive generator of discrete harmonic signals. The "speed/accuracy" ratio can be tuned due to input specifications. The actual accuracy and error analysis depend on the length of the DCT. We analyse the possibility of using our algorithm in JPEG image compression. However, application of the approximation method is possible in all problems using DCT. Our new approach to the DCT approximation is applicable to other transforms such as the DFT.
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