H.261, H.263, MPEG-1, and MPEG-2 Video Coding

¶ … H.261, H.263, MPEG-1, and MPEG-2 video coding standards in regard to Video Compression. The basis of this technology is founded on the idea of combining audio compression and video compression in order to create the concept of digital compression. When put together, these techniques literally revolutionized the way that audio and video data could be stored and/or transmitted electronically and more important, digitally.

The new world order is dominated by the internet. One of the reasons for the overall success of the internet is that anyone can see and hear complete film clips from the war in Afghanistan on Yahoo News or they can choose to watch a Will Ferrell comedy movie in its entirety. The objective is to discuss the state of the technology and offering some insight into how the process of Video Compression works. There are many new vendors and significant amounts of research in this field of study and the technology will continue to improve.

Baseline

There is and there will continue to be great demand on the producers of Video Compression technology because of the likes of the Internet, MP3 Players, new cell phones like the iPhone, DVD players, HDTV and new digital television standards, and those cool handheld digital cameras. These new 'must have necessities' are each pushing for the industry for newer and faster methods of compressing audio and video data. The technology is based on the ideas and techniques of MPEGs or the Moving Picture Experts Group.

MPEGs, pronounced M-pegs, are a standard that has been used to program or code both audio and visual data into either binary or hexadecimal formats. Examples of this type of coding can be seen every time that someone goes on YouTube to watch movies, music videos or over on iTunes to buy digital music. This compressed information is transferred into the MPEG format with special software so that it can be more easily moved, sent or stored in or on digital technologies. There are clear advantages to using the MPEG format as compared to other video and audio coding techniques. One major advantage is that MPEG files are significantly smaller because they use such an intricate compression methodology.

Many countries, schools and scientific bodies create standards. MPEG and other digital compression techniques are classified by these standards. For example, ANSI or the American National Standards Institute in the United States or the ISO, the International Organization for Standardization, create and manage these standards on a global scale. The Internet and all of the new advancements in the technological fields occur quickly and easily because, like Henry Ford, standardization permits new and existing technologies to be created faster and more cost effectively when a single standard is accepted on a global scale.

Techniques & Vendors

MPEG, and other video compression techniques, work through the combined efforts of the hardware and software. The combination of hardware and software take data and convert it into the format that is understood by software programs. An example of a software program that can read the logical sequencing of data in an MPEG format might be the REAL player that is often on most PCs. The format has evolved so MPEG formatted data can also be identified by other naming extensions like: MPG, MP2, MP3, MP4, MP7 and MP21. Today, MP7 is the current standard and MP21 will be the standard in the future.

MPEG is used for movies and videos that need to contain sound bites, but there are other standards that may not require motion, sound or both. These standards include several other choices like: JPEG, DV or H26. "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. DCT is the basis of standards such as JPEG, MPEG, H.261, and H.263." (Unknown) It is important to note that even though they are different from MPEG standards, the concepts associated with standardized compression methodologies are the same. If comparing the code of a movie MPEG and a picture jpeg, they would look similar. "JPEG is a lossy compression technique used for full-color or gray-scale images, by exploiting the fact that the human eye will not notice small color changes." (Unknown)

The compression techniques are not patented or owned by any single vendor. Because of the standardization of the technology, any and all vendors can apply the principles to their designed products. What that means is, if Andre Agassi takes a picture with his Canon digital camera in Germany, he can email it to Maria Sharapova's Canon camera in Russia and her camera will be able to understand his picture file and thus be able to display it.

Definitions

H.261 was developed by ITU-T around 1992. It is a video compression standard that works with integrated digital service networks. It works be compressing data at a rate of 64 P. kilobits per second. The P. means that the transfer ranges from 1 to 30 depending on possible ISDN channels available. The technology standard is used most often for video phones.

H.263 was also created as an ITU standard that is used to compress video and was based on the H.261 standard. The upgrade in technology basically allowed for better video quality on analog phone lines.

MPEG-1 was just that, the first version of the MPEG format for compressing video. This format was actually created for the CD-ROM and was designed for transmission rates around 1.5 Mbps. The International Standard (IS-11172) is free and can be accessed through the white papers on the internet.

MPEG-2 is to MPEG -- 1 as is H263 is to H261. The 2 version is just an upgrade in the technology and was mainly used to create DVD's and the old TV digital standards. The International Standard (IS-13818) is also free and can be accessed through the white papers on the internet.

Standards

These technologies get better all of the time. Currently there is a large amount of research being done using the MPEG-7 and MPEG -21 standards because the ANSI and ISO standards are well established. "MPEG-7, this standard, currently under development, is also called the Multimedia Content Description Interface. When released, the group hopes the standard will provide a framework for multimedia content that will include information on content manipulation, filtering and personalization, as well as the integrity and security of the content." (Unknown, 2003) MPEG -21, also called the Multimedia Framework, will be taking over the internet by the end of this year and early into next year as broadband technology gives the internet and the business community added speed and power.

People take for granted how impressive this technology really is. One cannot stop and think that sending a picture of cat through the internet would mean much but the technology that allows that picture to be sent also allows information to be sent from the space shuttle back to earth. Or, it allows Google Maps to take a picture of your back yard as though you were just a few feet above your house. It really does take a great deal of elaborate program logic to make this video compression a reality. There are four critical steps to making it work. "These steps are commonly called signal analysis, quantization and variable length encoding respectively. There are four methods for compression, discrete cosine transform (DCT), vector quantization (VQ), fractal compression, and discrete wavelet transform (DWT)" (Unknown) Luckily there are standard boards that keep all of those mathematical concepts in line.