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Topic: Video compression

Related Topics

Data compression

MPEG

Frames per second

Interlace

Sampling frequency

Universal code

Audio compression

Ultra High Definition Video

Discrete cosine transform

Digital television

Digital signal processing

Digital

Audio signal processing

Medical image processing

Digital image processing

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	Video compression - Wikipedia, the free encyclopedia
		With temporal compression only the changes from one frame to the next are encoded as often a large number of the pixels will be the same on a series of frames (About video compression).
		While lossless compression of video is possible, any lossless compression system will sometimes result in a file (or portions of) that is as large and/or has the same data rate as the uncompressed original.
		Other methods, such as fractal compression, matching pursuits, and the use of a discrete wavelet transform (DWT) have been the subject of some research, but are typically not used in practical products (except for the use of wavelet coding as still-image coders without motion compensation).
	en.wikipedia.org /wiki/Video_compression (914 words)

	Video compression: Facts and details from Encyclopedia Topic (Site not responding. Last check: 2007-11-07)
		Lossless data compression is a class of data compression algorithms that allows the original data to be reconstructed exactly from the compressed data....
		Video compression typically reduces this redundancy using lossy compression[Follow this hyperlink for a summary of this subject].
		A compression artifact is a particular type of data error that is typically the result of quantization in lossy data compression....
	www.absoluteastronomy.com /encyclopedia/v/vi/video_compression.htm (1298 words)

	Video codec - Wikipedia, the free encyclopedia
		A video codec is a device or software module that enables the use of data compression for digital video.
		A typical digital video codec design starts with conversion of camera-input video from RGB color format to YCbCr color format, and often also chroma subsampling to produce a 4:2:0 (or sometimes 4:2:2 in the case of interlaced video) sampling grid pattern.
		This emerging new standard is the current state of the art of ITU-T and MPEG standardized compression technology, and is rapidly gaining adoption into a wide variety of applications.
	en.wikipedia.org /wiki/Video_codec (1594 words)

	Video compression
		As data is discarded in the compression process, the resulting signal looses quality—especially during the copying process (which is essential for sophisticated editing).
		This means that 4:4:4 is a pure, uncompromised signal; 4:2:2 represents minimal and unnoticed compression; and 4:1:1, which is associated with DV camcorders, involves significant signal compression.
		Since MPEG2 compressed video relies on data in adjacent frames, if the video is stopped on a particular frame—as would be the case in editing—critical data will be missing.
	columbiaisa.50megs.com /camcord_video_compression.htm (1145 words)

	Video Compression Tutorial
		Discrete cosine transform is a lossy compression algorithm that samples an image at regular intervals, analyzes the frequency components present in the sample, and discards those frequencies which do not affect the image as the human eye perceives it.
		Compression is performed by locating self-similar sections of an image, then using a fractal algorithm to generate the sections.
		The standard uses DCT to compress the pixel data and is a form of lossy compression.
	www.wave-report.com /tutorials/VC.htm (1024 words)

	DIGITAL VIDEO: COMPRESSION: (Site not responding. Last check: 2007-11-07)
		Compression is a reversible conversion of data to a format that requires fewer bits, usually performed so that the data can be stored or transmitted more efficiently.
		Compression is analagous to folding a letter before placing it in a small envelope so that it can be transported more easily and cheaply.
		Compressed data, like the folded letter, is not easily read and must first be decompressed, or unfolded, to restore it to its original form.
	www.newmediarepublic.com /dvideo/compression/adv04.html (369 words)

	Video Compression Basics \| Hardware Secrets
		In order to reduce the video file size, a video compression technique is used, which works by removing from the video parts of the image that were already shown.
		You would need to play the video file from the beginning to build the image that is located in the middle of the movie, since in the middle of the file there is only information of what is different from the previous frame, not a complete image.
		This means that compressed video doesn’t have the same quality as the original video.
	www.hardwaresecrets.com /article/278 (714 words)

	MotionWavelets Video Compression - Aware, Inc. (Site not responding. Last check: 2007-11-07)
		Makers of PC video capture devices such as video capture boards, TV tuner boards and digital video cameras who want to add high quality video compression to their products at low cost and with minimal development effort.
		Compression methods based on a mathematical technique known as wavelets are widely acknowledged as producing results superior to traditional block-based compression schemes such as JPEG.
		Wide range of compression ratios/quality levels: A higher compression ratio allows you to store more compressed video files on your hard disk and to continuously capture video for a longer period of time before reaching limits imposed by maximum file or disk partition sizes.
	www.aware.com /products/compression/motionwavelets.htm (863 words)

	Video Compression: MPEG-4 and Beyond
		Compression ratio is the ratio of the size of the original video to the size of the compressed video.
		MPEG video compression standard [ MPEGa, LeGall91] is a layered, DCT-based video compression standard that results in VHS quality compressed video stream that has a bit rate of approximately 1.5Mbps at a resolution of approximately 352x240.
		Video compression is gaining popularity since storage requirements and bandwidth requirements are reducced with compression.
	www.cse.wustl.edu /~jain/cis788-99/ftp/compression (4201 words)

	MPEG-2 video compression
		This tutorial paper introduces the principles used for compressing video according to the MPEG-2 standard, outlines the general structure of a video coder and decoder, and describes the subsets ('profiles') of the toolkit and the sets of constraints on parameter values ('levels') defined to date.
		It is a three-part standard defining audio and video compression coding methods and a multiplexing system for interleaving audio and video data so that they can be played back together.
		This paper introduces the principles used in MPEG-2 video compression systems, outlines the general structure of a coder and decoder, and describes the profiles and levels defined to date.
	www.bbc.co.uk /rd/pubs/papers/paper_14/paper_14.html (4263 words)

	Video Compression: A Codec Primer
		Her less-than-dazzling grasp of video technology nearly made me fall off my chair, but as digital-video capture and editing became my specialty, I realized that many people are unfamiliar with the time required to capture and compress video, and the large file sizes required to store it.
		The truth is that the capture and compression process is slow and cumbersome, and raw, captured video is huge.
		We will take a brief look at the main ingredients of video compression, including the difference between compression schemes, hardware and software codecs, video-compressing freeware that works just fine, and architectures (which are like all-in-one packages that handle the entire compression and decompression process).
	www.webmonkey.com /97/34/index1a.html?tw=multimedia (369 words)

	Image and Video Compression Techniques
		Cosine transforms are used in JPEG compression for still images, MPEG-2 compression for moving video, and the FCC-standard for HDTV.
		Essentially, simple images are highly compressible, complex images less compressible and random noise images not compressible at all.
		Since it transmits only the moving portions of video images, it can be used to sense and emphasize motion or change in an image stream.
	www.autosophy.com /videcomp.htm (5727 words)

	Video Compression Glossary
		Cell compression is similar to MPEG and H.261 in that there is a lot of room for value-add on the compressor end.
		This produces a compression of 12-1 (or 8-1) since each 16 pixel block is represented by 32 bits (16-bit mask, and two 8-bit codebook indices).
		The codes used for compression are computed on the basis of the statistics gathered during the first pass with compressed texts being prefixed by a copy of the Huffman encoding table for use with the decoding process.
	bmrc.berkeley.edu /projects/mpeg/faq/mpeggloss.html (7679 words)

	Compression Links: Video area
		Our technology set is based on the Essential Video 4.0 codec, which is a flexible and dynamic codec which utilises a number of video compression techniques using our BestFirst algorithm; methods include vector quantisation, motion compensation and residual encoding.
		A growing concern for video researchers and broadcasters alike, is the assurance and maintenance of an acceptable service quality level for the distribution of video programming.
		It is intended as a tool for learning about compression techniques: from basic sampling and PCM to today's most advanced scalable embedded zerotree wavelet image compression technique and the MPEG video compression standard.
	www.compression-links.info /Video (5896 words)

	FLV Video Compression
		The video quality of most video formats is quite similar, except for the MP4 format which results in a slightly better size-quality performance.
		If you use one of these two formats you get great video quality at small filesizes, but since the software is quite new, it's possible that your visitors first have to upgrade their plugin.
		Compress with more keyframes (can be set in nearly every compression tool) to get rid of this problem.
	www.jeroenwijering.com /?item=FLV+Video+Compression (1081 words)

	Video Compression (Site not responding. Last check: 2007-11-07)
		As can be seen, this restriction in data rate means that the original signal must be compressed by a figure of approximately 83:1.
		This number seems all the more impressive when it is realized that the intent is to deliver very high quality video to the end user, with as few visible artifacts as possible.
		Lossy methods have to employed since the compression ratio of lossless methods (e.g., Huffman, Arithmetic, LZW) is not high enough for image and video compression, especially when distribution of pixel values is relatively flat.
	www.cs.cf.ac.uk /Dave/Multimedia/node245.html (244 words)

	HEI's DBS, MPEG and Video Compression Page
		Video compression is used for all the DBS satellite's video signals.
		The availability of the FEC information, transmitted together with the compressed video, provides the means to restore the signal to its error-free form.
		Video codecs, in an otherwise unconstrained environment, produce an instantaneous bit rate more-or-less proportional to the differences between video in adjacent video frames (similar in concept to frames of film).
	www.mpeg4.de /doc/hei/mpeg2.htm (2367 words)

	DataCompression.info - Video (Site not responding. Last check: 2007-11-07)
		The project was started as a reaction to the high cost of commercial implementations of audio and video compression code implementing the various components of H.323.
		Tool for the building of simple avisynth script from which is possible to automate the video compression with any codec and audio files into the formats: Mp3, Ogg and Wav; the tool have also a Compress Test and a Bitrate/size calc.
		A short paper with some links that describe the compression algorithm used with Microsoft Portrait, which is a demonstration project for video telephony.
	datacompression.info /Video.shtml (8285 words)

	Video Compression and Video Communication (MIT 6.344, Spring 2002)
		The goal of these lectures is to convey the basic principles and practice of video compression and video communication.
		This lecture finishes image compression (which was started in the prior lecture) and then begins to discuss video compression.
		Manipulating Temporal Dependencies in Compressed Video Data with Applications to Compressed-Domain Processing of MPEG Video, S. Wee, International Conference on Acoustics, Speech, and Signal Processing (ICASSP) 1999.
	web.mit.edu /afs/athena/course/6/6.344/www/Video/teaching_MIT6344.html (262 words)

	H263 Video Compression
		H.264 is being widely recognized as the future platform of video compression for applications such as new HDTV services, portable game console, mobile broadcast video services, video on solid-state camcorders, instant video messaging on cell phone.
		The new H.264 video compression standard is the first to be ratified by both the ISO/IEC and ITU-T. It raises the bar considerably compared to MPEG4-ASP and yields better picture quality while significantly lowering the bit rate.
		H.264 is considered the greatest achievement in video compression in the past 10 years and is already finding its way into many mainstream video applications.
	www.h263l.com (1570 words)

	digital video compression
		If you apply too much compression, lowering the data rate too far, you won’t be taking advantage of the full capacity of the system and the picture quality may suffer unnecessarily.
		The goal of data compression is to represent the same content using less data.
		The most common compression strategies used by codecs and the kinds of video they are intended to compress are described below.
	www.mapacourse.com /DVpages/compression.htm (220 words)

	MSU Lossless Video Codec
		This codec is intended for lossless video compression (used for saving master copies or intermediate rendering results).
		Compression method allows you to choose compression algorithm - the new one or the old one.
		The new one is much faster on compression and decompression, but the old one gives better compression on most files (but on some files the new method works better).
	www.compression.ru /video/ls-codec/index_en.html (851 words)

	Amazon.com: Video Compression: Books: Peter Symes,Peter D. Symes (Site not responding. Last check: 2007-11-07)
		From the fundamentals of the sampled images that form the actual input to any compression system to available compression tools and performance considerations, the material is clear, concise, and richly relevant.
		If you are looking for a basic understanding of the various video compression standards, then this book is for you.
		If you know nothing or little about video compression and you don't want to mess with complicated math, this is the book you should read.
	www.amazon.com /exec/obidos/tg/detail/-/0070633444?v=glance (1213 words)

	Video Compression (Site not responding. Last check: 2007-11-07)
		In MPEG video compression, the motion compensated prediction step is very computationally intense.
		In this project we explore the use of high performance parallel computers to compress video sequences.
		Shen and E. Delp, "A Spatial-Temporal Parallel Approach For Real-Time MPEG Video Compression," Proceedings of the 25th International Conference on Parallel Processing, August 13-15, 1996, Bloomingdale, IL, pp.
	dynamo.ecn.purdue.edu /~ace/compression/compression.html (295 words)

	H261 Video Compression
		H.261 is designed to run at multiples of 64Kbps data rates from 1x to 30x.
		Although some early streaming solutions commandeered its video compression algorithm, discarding much of communication layer and using TCP/IP instead.
		Please contact me for assistance on Video Compression and Streaming projects.
	www.h261.com (227 words)

	Direct Broadcast Satellite (DBS) and Broadcasting Using Video Compression -- Other Information (Site not responding. Last check: 2007-11-07)
		Basil Halhed, the author of this article and an HEI founder, has been involved with video compression RandD and applied compressed video including videoconferencing, broadcasting, DBS, MMDS and satellites for more than 35 years.
		He recalls, “ I remember the days when a codec occupied three eight-foot high racks of equipment and could operate at bit rates as low as 28 Mbps, a 5:1 compression ratio!
		If the above has piqued your interest in video compression, you might also like to read Halhed's articles on the video compression for video teleconferencing; the techniques are quite similar, only the degree of processing is greater.
	www.heiconsulting.com /mpeg2i.html (213 words)

	RAD Game Tools
		Bink Video is our ubiquitous game video codec - it has been used in 2,900 games!
		It is this popular because it looks great, it uses absolutely minimal CPU and memory, it runs on all of the platforms out there, it supports high-end features like 5.1 audio and pixel shaders, and has a terrific run-time API.
		The latest version includes video compression with twice the video quality and now uses the Bink audio codec for perceptually lossless 8 to 1 compression!
	www.radgametools.com (609 words)

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