I. Dalgic and F. A. Tobagi, "Characterization of quality and traffic for various video encoding schemes and various encoder control schemes," Tech. Rep. CSL--TR--96--701, Stanford University, Departments of Electrical Engineering and Computer Science, Aug. 1996.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....are VBR encoded with high peak to mean ratios. The focus on VBR encoded video is motivated by the fact that for the same perceived video quality, Constant Bit Rate (CBR) encoding produces an output rate significantly higher than the average rate of the corresponding VBR encoding for action movies [1]. Therefore schemes for VBR encoded video that achieve near 100 channel utilization, while keeping losses at a negligible level, can allow for significantly more video connections than can CBR encoded video. Our prefetching protocols achieve the constant perceptual quality, responsiveness to ....

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL TR96 701, Stanford University, Departments of Electrical Engineering and Computer Science, August 1996. 24

....scale is kept constant to maintain high video quality even for high action scenes. For the same quality level the file size and average bit rate of a Constant Bit Rate (CBR) encoded movie or sports clip are typically two times or more than the file size and average bit rate of the VBR encoding [4, 37]. Our first contribution is to develop a unified scheme for admission control and resource reservation in the proxy server as well as the local access network. Toward this end we first de velop a disk model and derive the effective disk bandwidth for the retrieval of continuous media trattic with ....

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL TR96 701, Stanford University, Departments of Electrical Engineering and Computer Science, August 1996.

....manner. Video is typically encoded (1) without rate control (i.e. open loop) which results in constant video quality but highly variable traffic (bit rate) or (2) with rate control (i.e. closed loop) which results in some variations in the video quality but nearly constant bit rate traffic [11], 12] Video traffic smoothing techniques, e.g. 13] are expected to be widely employed for the streaming of stored (prerecorded) video. Note that all videos distributed through caches are prerecorded. These smoothing techniques can (1) significantly reduce the traffic variability of ....

I. Dalgic and F. A. Tobagi, "Characterization of quality and traffic for various video encoding schemes and various encoder control schemes," Tech. Rep. CSL--TR--96--701, Stanford University, Departments of Electrical Engineering and Computer Science, Aug. 1996.

....that the videos are VBR encoded with high peak to mean ratios. The motivation for our approach is that, for the same perceived video quality, Constant Bit Rate (CBR) encoding produces an output rate significantly higher than the average rate of the corresponding VBR encoding for action movies [3]. CBR traffic allows for nearly 100 link utilization; the number of connections that can be carried over a link of given capacity is roughly the link capacity divided by the CBR rate (assuming homogeneous connections) The number of VBR connections that can be transmitted simultaneously is the ....

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL--TR--96-- 701, Stanford University, Departments of Electrical Engineering and Computer Science, August 1996.

....during compression, which causes quality degradation in the encoded video. With CBR encoding, the bit rate of the resulting encoded video actually fluctuates around the target CBR rate; but the video can be transmitted at the CBR rate and a small smoothing buffer at the client ensures continuity [8, 25]. For open loop VBR encoding, the quantization scale remains constant throughout the encoding process, which often produces highly variable bit rates. Digital video distribution systems using satellite and cable have avoided using VBR video due to its burstiness. Nevertheless, for a given movie ....

....distribution systems using satellite and cable have avoided using VBR video due to its burstiness. Nevertheless, for a given movie or sporting event and for the same quality level, the average bit rate of a CBR MPEG encoding is typically 2 times or more the average bit rate of a VBR MPEG encoding [8, 57]. Therefore with VBR video there is potential for increased system efficiency. We note that to our knowledge our study is the first to investigate near VoD systems using periodic broadcasting of VBR encoded video. Although non uniform segmentation can greatly reduce start up latency, for many ....

[Article contains additional citation context not shown here]

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL-TR96 -701, Departments of Electrical Engineering and Computer Science, Stanford University, August 1996.

....that the videos are VBR encoded with high peak to mean ratios. The motivation for our approach is that, for the same perceived video quality, Constant Bit Rate (CBR) encoding produces an output rate significantly higher than the average rate of the corresponding VBR encoding for action movies [2]. CBR traffic allows for nearly 100 link utilization; the number of connections that can be carried over a link of given capacity is roughly the link capacity divided by the CBR rate (assuming homogeneous connections) The number of VBR connections that can be transmitted simultaneously is the ....

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL--TR--96-- 701, Stanford University, Departments of Electrical Engineering and Computer Science, August 1996.

....addition, the broadcast schemes impose particular synchronization relations between the different segments of the same video. Finally, the bandwidth requirements are further compoundedby the fact that most periodic broadcast schemes assume Constant Bit Rate (CBR) coded video. It has been observed [5] that, for the same video quality, the average CBR bandwidth demands far exceed the average bandwidth demands of Variable Bit Rate (VBR) coded video. In addition, VBR coding schemes are becoming commonplace (MPEG 1 and MPEG 2) and extensive libraries of video material are already available in VBR ....

I. Dalgic and F. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL--TR--96--701, Department of Electrical Engineering and Computer Science, Stanford University, August 1996.

....scale is kept constant to maintain high video quality even for high action scenes. For the same quality level the file size and average bit rate of a Constant Bit Rate (CBR) encoded movie or sports clip are typically two times or more than the file size and average bit rate of the VBR encoding [17], 18] Our first contribution is to develop a unified scheme for admission control and resource reservation in the proxy server as well as the local access network. Towards this end we first develop a disk model and derive the effective disk bandwidth for the retrieval of continuous media traffic ....

I. Dalgic and F. A. Tobagi, "Characterization of quality and traffic for various video encoding schemes and various encoder control schemes," Tech. Rep. CSL--TR--96--701, Stanford University, Departments of Electrical Engineering and Computer Science, Aug. 1996.

....during compression, which causes quality degradation in the encoded video. With CBR encoding, the bit rate of resulting encoded video actually fluctuates around the target CBR rate; but the video can be transmitted at the CBR rate and a small smoothing buffer at the client ensures continuity [8] [9]. For open loop VBR encoding, the quantization scale remains constant throughout the encoding process, which often produces highly variable bit rates. Digital video distribution systems using satellite and cable have avoided using VBR video due to its burstiness. Nevertheless, for a given movie ....

....Digital video distribution systems using satellite and cable have avoided using VBR video due to its burstiness. Nevertheless, for a given movie or sporting event and for the same quality level, the average bit rate for CBR video is typically 2 times or more the average bit rate of VBR video [9] [10] Therefore with VBR video there is potential for increased system efficiency. Although non uniform segmentation can greatly reduce startup latency, for many practical circumstances the start up latency remains unacceptably high for CBR encoded video. When a near VoD system broadcasts ....

[Article contains additional citation context not shown here]

I. Dalgic F. A. Tobagi, "Characterization of quality and traffic for various video encoding schemes and various encoder control schemes," Tech. Rep. CSL-TR-96-701, Departments of Electrical Engineering and Computer Science, Stanford University, August 1996.

....scale is kept constant to maintain high video quality even for high action scenes. For the same quality level the file size and average bit rate of a Constant Bit Rate (CBR) encoded movie or sports clip are typically two times or more than the file size and average bit rate of the VBR encoding [16], 17] Our first contribution is to develop a unified scheme for admission control and resource reservation in the proxy server as well as the local access network. Towards this end we first develop a disk model and derive the effective disk bandwidth for the retrieval of continuous media traffic ....

I. Dalgic and F. A. Tobagi, "Characterization of quality and traffic for various video encoding schemes and various encoder control schemes," Tech. Rep. CSL--TR--96--701, Stanford University, Departments of Electrical Engineering and Computer Science, Aug. 1996.

....vary. 2. Variable memory use per cycle: Since the amount of data that is pre fetched must be adequate to sustain a cycle of consumption, the memory use can be different from cycle to cycle. Many studies propose encoding, data placement and scheduling policies to support VBR streams. Dalgic et al. [12], for example, propose a Constant Quality VBR (CQ VBR) encoding scheme, which controls the peak to average bitrate ratio between 2 and 3. Chang [9] and Makaroff [17] propose scheduling policies that retrieve a constant number of frames per IO (rather than a constant number of bits) These ....

I. Dalgic and F. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Stanford Technical Report CSL-TR-96-701, August 1996.

....the control parameters. Our design goal is to avoid, as much as possible, display glitches due to variability and delays in the input stream. Studies have shown that even just losing 0:1 of data can cause significant degradation in display quality, resulting from inter frame decoding dependencies [14, 15]. Therefore, in computing our control parameters we take a conservative approach. That is, we assume the worst case disk latency, as well as peak data consumption and input rates. Of course, we cannot prevent glitches due to data not showingup at the client. However, we do compute how much main ....

I. Dalgic and F. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Stanford Technical Report CSL-TR-96-701, August 1996.

....VBR encoded with high peak to mean ratios. The focus on VBR encoded video is motivated by the fact that for the same perceived video quality, Constant Bit Rate (CBR) encoding produces an output rate significantly higher than the average rate of the corresponding VBR encoding for action movies [1]. Therefore schemes for VBR encoded video that achieve near 100 channel utilization, while keeping losses at a negligible level, can allow for significantly more video connections than can CBR encoded video. Our prefetching protocols achieve the constant perceptual quality, responsiveness to ....

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL--TR--96-- 701, Stanford University, Departments of Electrical Engineering and Computer Science, August 1996.

....during compression, which causes quality degradation in the encoded video. With CBR encoding, the bit rate of resulting encoded video actually fluctuates around the target CBR rate; but the video can be transmitted at the CBR rate and a small smoothing buffer at the client ensures continuity [9] [3]. For open loop VBR encoding, the quantization scale remains constant throughout the encoding process, which often produces highly variable bit rates. Digital video distribution systems using satellite and cable have avoided using VBR video due its burstiness. Nevertheless, for a given movie or ....

....rates. Digital video distribution systems using satellite and cable have avoided using VBR video due its burstiness. Nevertheless, for a given movie or sporting event and for the same quality level, the average bit rate for CBR video is typically 2 times or more the average bit rate of VBR video [3] [16] Therefore with VBR video there is potential for increased system efficiency. Although non uniform segmentation can greatly reduce start up latency, for many practical circumstances the start up latency remains unacceptably high for CBR encoded video. When a near VoD system broadcasts ....

[Article contains additional citation context not shown here]

I. Dalgic and F. A. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Technical Report CSL-TR-96-701, Departments of Electrical Engineering and Computer Science, Stanford University, August 1996.

....to the statistics collected by the Stanford University Wireless Computing Group [2] the average packet loss rate is about 3:6 in a wireless environment and occurs in a bursty fashion. According to the study conducted by the Stanford Multimedia Network Group for a teleconferencing application [8, 9], the duration of a burst, or the number of successive packets lost, ranges from one to seven packets. In terms of an ATM network, since each packet contains 56 bytes or 448 bits of data, each burst of loss translates to a loss of 448 to more than 3,000 consecutive bits, which can be a significant ....

I. Dalgic and F. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Stanford Technical Report CSL-TR-96-701, August 1996.

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I. Dalgic and F. A. Tobagi, "Characterization of quality and traffic for various video encoding schemes and various encoder control schemes," Tech. Rep. CSL--TR--96--701, Stanford University, Departments of Electrical Engineering and Computer Science, Aug. 1996.

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I. Dalgic and F. Tobagi. Characterization of quality and traffic for various video encoding schemes and various encoder control schemes. Stanford Technical Report CSL-TR-96-701, August 1996.

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