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Communication plays a very pivotal role in today’s fast paced world. Advanced techniques assist in information exchange. Audio and video communication has become the order of the day with companies opting for video conferencing and more lately, telepresence!
High Definition Television (HDTV), teleconferencing, satellite communications; storage of movies and music in digital form would not be possible without a compressing it to a significant extent. Now, let us discuss more about digital video compression; internet video compression to be precise.
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Basics of Video Compression
Events that occur more frequently are assigned fewer bits and events that occur less frequently are assigned codes with more bits, as information is inversely proportional to frequency of occurrence; this is called variable length encoding.
There is always a trade-off between image quality and file size. Various compression standards use different compression algorithms to balance these two parameters effectively. So, now let us move on to the Internet video compression standards.
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Internet Video Compression Standards and Their Applications
MPEG is the acronym for the Moving Pictures Experts Group. MPEG is a group that develops standard audio and video formats. There are different MPEG standards implemented for use in specific applications.
Here are some of the most popular internet video compression standards -
• MPEG-1: It is a compression standard for audio and moving pictures, with support for bit rates up to 1.5 Mbit/sec.
This is a popular standard for streaming videos as .mpg files over the internet. The ubiquitous MP3 format, standing for MPEG 1 Audio Layer 3, is a famed standard for audio compression.
• MPEG-4: It is a popular object-based compression standard for multimedia compression. Objects in a frame are tracked independently and compressed together to form an MPEG4 stream. The result is an efficient compression standard flexible over a vast range of bit rates. Its interactivity provides developers to control independent objects in a scene with ease.
• DV: DV is a high-resolution digital video format which employs lossy compression where certain redundant information in a file is permanently deleted, so that even when the file is uncompressed, only a part of the original information is still there.
• H.261 and H.263: H.261 is standard for duplex communication over ISDN lines and supports data rates in multiples of 64Kbit/s. The algorithm uses intraframe and interframe compression. H.263 is an enhanced version of the H.261 codec that improves quality of video streaming over modems.
• DivX Compression: It is an application that employs MPEG-4 compression standards to facilitate fast downloads over DSL/cable modem, without compromising on video quality.
• Flash Video: The most popular compression format for videos on the internet is .flv or Flash Video. FLV and F4V are container file formats which play videos on the internet through Adobe Flash Player. Encoding of audio and video data for FLV files are same as those for SWF files. This format is the favorite choice for embedded video on the web as it compresses video to low bitrates and maintains optimum quality. Leading video sites like YouTube, Reuters, Yahoo! Video, Metacafe, Google Video upload videos in this format.
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Importance of Internet Video Compression
With the advent of many better formats like Matroska that provides excellent quality at lower bit rates, and the continuous speeding up of internet connections, evolution of video compression techniques is expected at an extremely rapid pace.
More so, the hopes given by grid computing are really promising; no wonder we may see few new internet video compression standards pretty soon.
Here's some more help on Compressing Large QuickTime Files into Smaller Video Files