It’s sure that HP has reported the expected date was “this summer” when they revealed the webOS slate on February 9th, to which many analysts responded, “too late.” Then, rumor said HP will start shipping the webOS-empowered tablet by the end of March, citing sources from HP’s “upstream component partners”.

To DVD viewers who have some insight into what makes DVDs tick, MPEG is the name of the method used to compress the audio and video into bit stream tokens. These compressions–not detectable by the normal viewer–allow data to effectively fit into smaller storage areas. That’s why an entire movie can fit onto a single DVD disc. This article sums up the evolution of several MPEG compression types.

The MPEG–1 standard was developed for video transmission rates of about 1.5 million bits per second. The resolution of video at this rate is 352 X 240 at 30 frames per second; this creates a video of slightly lower quality than a VCR video.

A VCD (Video Compact Disk) is a CD that can play moving pictures and sounds. Each CD has the capacity to hold 650MB to 700MB of data. That translates to 74 to 80 minutes of video and stereo sound. This format was an offshoot of MPEG–1 technology.

In 1994, the Motion Pictures Coding Experts Group and the ISO agreed upon the MPEG–2 standard. MPEG–2 is the coding format used in most DVD movies today. This format has characteristics similar to MPEG–1, but incorporates TV broadcast interlaced video. (To learn about interlaced video, read our article: What is Interlacing .)

MPEG–2 introduced transport stream technology; this is the ability to carry digital video and audio over unreliable media such as the Internet. MPEG–2 can also be used to compress a two hour movie onto a single DVD, offering resolutions of 720 X 480 and 1280 X 720 at 60 frames per second. MPEG–2 audio also introduced multi–channel support–up to 5.1 audio channels and a low bit rate encoding–allowing complex stereo sound to accompany movies for the first time, such as Dolby ProLogic Surround Sound signals.

In 1998, the Motion Pictures Coding Experts Group and the ISO standards agreed upon the MPEG–4 standard. MPEG–4 is the first network–based technology platform and is designed for streaming media across the World Wide Web, interactive graphics (such as videophones) and digital broadcast television. MPEG–4 is based on MPEG–1, MPEG–2 and Apple’s QuickTime technology. The compression in an MPEG–4 file is smaller than a JPEG or QuickTime file, allowing for more efficient storage and data transfer.

With common use of streaming media broadcasts online and other areas (such as cell phones), a standard had to be implemented for real–time and non real–time content. With the increasing need and demand for audio and video across a variety of media–including DVD Video, Audio CDs, streaming video on the Internet, Digital Audio Broadcasting, and a number of other formats–the Moving Picture Experts Group developed standardized tools to describe the multimedia content. MPEG–7 is the standard for production, distribution and content access for interactive multimedia, mobile multimedia, interactive graphics, and enhanced digital television.

As will always be the case, new needs crop up–this time, security. MPEG–21 is the latest standard designed to meet this challenge. With high–volume media exchanging hands freely across the Internet, the new MPEG–21 format allows users to secure their privacy to prevent unauthorized access or modification of their data.

MPEG works hard to keep communication data transfer standards in pace with the needs of our society. It’s a tough job, but someone has to do it.