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Topic: Constant bit rate

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Variable bit rate

Bit rate

Bits per second

Data transfer rate

Data compression

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	Constant bit rate - Wikipedia, the free encyclopedia
		When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be consumed is constant.
		CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity.
		CBR would not be the optimal choice for storage as it would not allocate enough data for complex sections (resulting in degraded quality) while wasting data on simple sections.
	en.wikipedia.org /wiki/Constant_bit_rate (190 words)

	RealJukebox FAQ - Constant and Variable Bit Rate Encoding
		Constant Bit Rate (CBR) encoding is an encoding method that varies the quality level in order to ensure a consistent bit rate throughout an encoded file.
		In order to maintain constant bit rate throughout the file, difficult passages (for example, passages containing a relatively wide stereo separation), may be encoded with fewer than the optimum number of bits.
		Constant Bit Rate encoding produces MP3 file sizes that are easily predicted by multiplying the bit rate by the duration.
	service.real.com /help/faq/rjbvbrfaq.html (765 words)

	Bit rate (Site not responding. Last check: 2007-10-09)
		In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) "point".
		While often referred to as "speed", bit rate does not measure distance/time but number of bits/time, and thus should be distinguished from the "propagation speed" (which depends on the transmission medium and has the usual physical meaning).
		There are typically eight bits in a byte (octet), but communications data rates are almost never expressed in bytes per second, with the notable exceptions of disk and memory I/O transfer rates.
	www.free-download-soft.com /info/bitrate.html (407 words)

	Variable bit rate - Wikipedia, the free encyclopedia
		Variable bit rate (VBR) is a term used in telecommunications, relating to the quality of service.
		When referring to codecs, variable bit rate encoding varies the amount of output data in each time segment based on the complexity of the input data in that segment.
		The goal is to maintain constant quality instead of maintaining a constant data rate.
	en.wikipedia.org /wiki/Variable_bit_rate (160 words)

	Riptastic! Frequently Asked Questions (Site not responding. Last check: 2007-10-09)
		CBR encoding means that the bit rate, or rate of data consumption per unit of time, is unchanging throughout the entire file.
		Because the actual bit rate varies depending on the complexity of the music, for VBR the bit rates shown on the configuration dialog are estimations and won't necessarily match the “standard” bit rates you're used to.
		Since the bit rate is constant and the same for all frame headers in a CBR-encoded MP3 file, it suffices to retrieve the bit rate from any frame for use in computing the file's duration.
	www.riptastic.com /support/faq.htm (1781 words)

	CBR - Case Based Reasoning, Constant Bit Rate
		Constant Bit Rate, a type of traffic that requires a continuous, specific amount of bandwidth over the ATM network (e.g., digital information such as video and digitized voice).
		Constant Bit Rate: An ATM service category which supports a constant or guaranteed rate to transport services such as video or voice as well as circuit emulation which requires rigorous timing control and performance parameters.
		CBR is used for connections that depend on precise clocking to ensure undistorted delivery.
	www.auditmypc.com /acronym/CBR.asp (492 words)

	Two-pass MPEG-2 variable-bit-rate encoding
		To assign bit rates to specific segments of a video sequence such that we attain constant visual quality, it is optimal to have knowledge of the characteristics of the entire video.
		The bit allocation for the macroblocks in the second pass is done by lexicographically ordering all of the blocks over the entire sequence, but constrained by the buffer and channel requirements.
		The bit rate that is fitted to the data is derived from Table 2, for an average bit rate of 4 Mb/s.
	www.research.ibm.com /journal/rd/434/westerink.html (8477 words)

	Single-pass constant- and variable-bit-rate MPEG-2 video compression
		Another advantage of a CBR stream is that the transmitted signal may be terminated at any time and the user is assured of maintaining a rate close to the target rate.
		Constant K (measured in Mb/s) is modulated for each video interval to ensure that the average rate of the compressed stream meets the desired target.
		Constant K is modulated for each GOP to ensure that the total number of bits produced by the VBR stream is not more than the size of the storage or retrieval device, e.g., a DVD disc.
	www.research.ibm.com /journal/rd/434/mohsenian.html (9428 words)

	3 (Site not responding. Last check: 2007-10-09)
		It means that data output specifies a fixed bit rate so that data is sent in a steady stream and objects generate packets at a constant bit rate.
		Using CBR the quality of the streamed audio/video has to reduce the quality to fit the fixed bit rate.
		So the aim is to use all the available bit rate and the quality of the streamed file so high that it doesn’t overflow the available bit rate.
	osiris.sunderland.ac.uk /~cc3amo/cbr.htm (150 words)

	Source Analysis And Characterisation
		The mean rate is not quite 256 kb/s due to the nature of the design of the codec, however that was the aim for the mean bit rate.
		The 384 kb/s two layer codec produced a combined bit rate as is shown in Figure 2.2, which is quite different to that produced by the one layer codec and shown in Figure 2.1.
		If the two layers are considered together then the total mean bit rate would be 408 kb/s and the peak bit rate would be 1109 kb/s and the peak to mean ratio would be 2.7, which is again close to that found in other studies [87].
	www.eeng.dcu.ie /~murphyj/the/the/node34.html (1446 words)

	United States Patent: 5,604,731
		The invention of claim 2 wherein each of said stored rates within said second memory represents the instantaneous transmission rate that would be required to support the transmission of said series of data segments so that the represented video signal is received at said second site in real-time.
		The invention of claim 8 wherein each of said stored rates within said second memory represents the instantaneous transmission rate that would be required to support the transmission of said series of data segments so that the represented video signal is received at said second site in real-time.
		In response, the rate value R.sub.0 (associated with the initial segment, S.sub.0, of the particular compressed video data program stored within video source 207) is transmitted from video data transmission rate memory 208 to network renegotiation controller 213.
	www.eecs.berkeley.edu /~dtse/rcbr_patent.html (4475 words)

	Bit Rate (Site not responding. Last check: 2007-10-09)
		The formal abbreviation for "bit per second" is "bit/s" (not ''bits/s'').
		For large bit rates, SI prefixes are used, ''not'' binary prefixes: There are typically eight bits in a byte (''octet''), but communications ''data rates'' are almost never expressed in bytes per second, with the notable exceptions of disk and memory I/O ''transfer rates''.
		The bit rates in this section are approximately the ''minimum'' that the
	www.wwwtln.com /finance/19/bit-rate.html (1037 words)

	Glossary (Site not responding. Last check: 2007-10-09)
		CBR - Common abbreviation for Constant Bit Rate.
		Cell Loss Priority - A bit in the ATM cell header that indicates that if all other factors are equal for two cells and there is a need to discard a cell, the cell with the CLP bit set is to be discarded.
		Constant Bit Rate - Information that is represented in a digital form by a constant stream of bits is said to have a constant bit rate.
	www.webtorials.com /public/dnagloss/cgloss.htm (496 words)

	Encyclopedia: Constant bit rate (Site not responding. Last check: 2007-10-09)
		In the fields of packet-switched networks and computer networking, the traffic engineering term Quality of Service (QoS) refers to the probability of the telecommunication network meeting a given traffic contract, or in many cases is used informally to refer the probability of a packet succeeding in passing between two...
		Data transmission In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point.
		Average bit rate refers to the average amount of data transfered per second.
	www.nationmaster.com /encyclopedia/Constant-bit-rate (396 words)

	Providing constant bit rate upstream data transport in a two way cable system by scheduling preemptive grants for ...
		CBR and ABR data are also different on the prospects of the traffic patterns.
		CBR sources produce data in a constant rate fashion while the ABR sources are usually in the burst mode.
		Having described preferred embodiments of a novel constant bit rate mechanism in a contention based medium access control (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings.
	www.freepatentsonline.com /5966163.html (5177 words)

	Station Information - Constant bit rate
		CBR is also sometimes used to describe a method of encoding audio, where the output of the codec is constrained to produce a constant bit rate.
		Some other audio codecs use CBR, others are designed to be used in a VBR mode.
		Both CBR and VBR can be used for MP3 encoding.
	www.stationinformation.com /encyclopedia/c/co/constant_bit_rate_1.html (74 words)

	A Constant Bit Rate Component
		CBR is an applicate layer component that generates constant traffic during the simulation.
		The CBR component can be linked to any lower layer component, provided their inports and outport are compatible.
		FinishTime specifies a time after which the CBR component won't be active, i.e., it won't create more packets; this gives the network a chance to clean up packets in transit, forcing packets sent earlier to reach their destinations.
	www.cs.rpi.edu /~cheng3/sense/cbr.h.html (946 words)

	Method and apparatus for storing and accessing multiple constant bit rate data - Patent 6282207
		To facilitate storage of multiple constant bit rate programs, current servers require the bit rates of various programs to be integer multiple of one another such that the extents of any given program are of equal size and the extents across programs are integer multiples of each other.
		The extent is a number of bits that can be read from memory during a data read period for a given bit rate, rounded up to the next full packet.
		For example, if the bit rate for movie 1 (M.sub.1) is 5 Mbps and the service period is 1.8 seconds, then the extent size will be 5984.04 packets (assuming 188 byte MPEG packets are used to carry the data).
	www.freepatentsonline.com /6282207.html (3481 words)

	BROADCASTPAPERS.COM (Site not responding. Last check: 2007-10-09)
		These implementations apply a constant bit-rate control algorithm to the compression engine, to make sure that every picture can be delivered through the channel at the correct time.
		The DCT coefficients are all signed 11- bit integers except for the dc term which is unsigned up to 11 bits.
		The result is a a significant reduction in the number of coded bits with no visually apparent difference between the decoded output and the original source data.
	www.broadcastpapers.com /sigdis/GVGMPEG202.htm (633 words)

	Method of transferring structured data of constant bit rate traffic in an ATM network - US Patent 5703878 (Site not responding. Last check: 2007-10-09)
		It requires a constant bit rate at source and destination, a timing relationship between source and destination and permits to transfer structured information between source and destination.
		It is therefore a principal object of the invention to provide a method to transfer structured data of constant bit rate traffic in an ATM network, wherein, when a cell is lost during transmission, the receiver does not need to know the number of octets of user information contained in the lost cell.
		It is another object of the invention to provide a method to transfer structured data of constant bit rate traffic in an ATM network which does not require reading of the pointer of P-formats and identification of the start of the structured data field.
	www.patentstorm.us /patents/5703878.html (2432 words)

	Ethnomusicology C169
		It is 480 x 480 pixels, variable bit rate, Mpeg 2, at approx.
		This format is constant bit rate, in contrast to Mpeg 2.
		This frame is a bit map (720 x 480) of digitized video that is a direct capture of the original source.
	www.ethnomusic.ucla.edu /courses/c169-269/quiz2terms.htm (821 words)

	Re: unspecified bit rate vs. constant bit rate (Site not responding. Last check: 2007-10-09)
		Re: unspecified bit rate vs. constant bit rate
		UBR and CBR are terms commonly associated with ATM services.
		CBR specifies a bit rate which can be continuously met over time, with little or no variation in the bit rate.
	www.mailarchive.ca /lists/comp.dcom.sys.cisco/2003-08/0524.html (172 words)

	Variable Bit Rate (Site not responding. Last check: 2007-10-09)
		The stream is bursty; that is, sometimes the bandwidth required is low and other times it is high.
		Circuit-switched networks are engineered to provide enough bandwidth in each circuit or virtual circuit to handle the peak rate required by the VBR application.
		Packet-switched networks are engineered to provide enough bandwidth to handle the average rate required by the set of VBR applications that are running.
	www.uta.edu /cse/ye/6392/presentation2/qos_2.htm (132 words)

	Variable vs. Constant Bit Rate Question: DVD Authoring (Site not responding. Last check: 2007-10-09)
		If you limit the VBR peaks to the CBR rate, you guarantee that you VBR cannot be better than your CBR, only smaller.
		In cbr I use severe pixelization whith is all gone with vbr.
		This results in higher quality video than CBR encoding at the same overall bit-rate, or the same level of quality as CBR encoding at a lower overall bit-rate.
	www.thehelparchive.com /new-2943116-86.html (1481 words)

	* Publications * (Site not responding. Last check: 2007-10-09)
		To avoid excessive losses the transmission rate of the ABR applications should be modulated by the amount of remaining resources.
		Since the ABR applications use the remaining resources after CBR (Constant Bit Rate) and VBR (Variable Bit Rate) applications have been accommodated, the ABR rate should be controlled through a feedback based flow control scheme to avoid excessive losses.
		While in a given state, the VBR source is supposed to transmit at a fixed rate; the VBR time scale is then defined in terms of the time constant associated with the rate of change of the rate of the VBR source.
	www.cdsp.neu.edu /info/students/tdag/aboutme/publications.html (1023 words)

	VideoHelp.com :: View topic - Constant Bit Rate vs. variable Bit Rate
		If your video will fit using cbr ~2.5 mbits then there is really no reason to use vbr, it will only take longer to encode.
		The point of vbr is to achieve the SAME level of quality that you can get with cbr but in a much smaller filesize.
		For instance if you encoded at an avg of 2mbits you would probably get about the same quality as you would get with cbr at 2.5mbits but you would be able to fit considerably more content onto each disk with vbr.
	www.videohelp.com /forum/viewtopic.php?t=89892 (810 words)

	Medium Bit Rate (Site not responding. Last check: 2007-10-09)
		28K bit rate is also economical of space- frequently if some device is boasting '10 hours of solid music!' from playing mp3s, it is probably assuming 128K mp3s.
		C128, CokaCoda constant bit rate of 128K, falls solidly into the LAME camp with regard to its sonic characteristics.
		Fraunhofer were brilliant with the low bit rate algorithms- but their evident decision to push the accuracy of 12-16K at the cost of introducing a _severe_ ringing at the cutoff point is a very bad decision, sonically.
	www.airwindows.com /encoders/mediumbitrate (2134 words)

	Constant bit rate (CBR) compression (Site not responding. Last check: 2007-10-09)
		This is usually to fit within a given bandwidth such as that available on a video tape recorder or a constant bit rate transmission channel.
		Using constant bit rate means that the quality is altered to reduce the information to fit the fixed bit rate.
		As overflowing the available bit rate could have disastrous results with bits being lost, the aim is always to use just under the available bit rate.
	www.quantel.com /domisphere/infopool.nsf/HTML/58CCCE6FB45056A580256C87004D3034 (200 words)

	Constant Bit Rate (Site not responding. Last check: 2007-10-09)
		Historically, voice and old video codecs produced a constant stream of bits.
		These applications are described as constant bit rate (CBR) applications because they require a specific minimum amount of bandwidth.
		Traditionally these applications have run in circuit-switched environments where they have fixed, dedicated bandwidth.
	www.uta.edu /cse/ye/6392/presentation2/qos_1.htm (60 words)

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