Many people, especially those with satellite TV receivers have heard of MPEG. MPEG is a standard to reduce the size of the video signal so that it can be easily transferred. This is known as a "signal compression. Compressed Digital Video (CDV) is comparable to using MP3 files for music. This makes the file smaller without damaging it, so it takes less time to download (less bandwidth), and other tracks are stored on the player.
CDV reduces the bandwidth of the signal Requirements for a TV signal for transmission over the Internet, DVD, cable or satellite allows. This is necessary because an uncompressed video signal is very large. high-resolution files are much larger than the files in standard definition.
HDTV
A standard-definition DVD format movie file is about 3 GB per hour. An uncompressed 1280 X 720 (HDTV) file size is over 150 GB / hour. An uncompressed 1920 X 1080 (HDTV) file size is about 350 GB per hour. An MPEG-2 (CDV)HDTV> file is about 9 GB / hour. An MPEG-4 (CDV) HDTV file size is about 5 GB / hour.
The early use of CDV (for standard definition programming) was discovered by the satellite TV companies DirecTV and Dish Network.
CDV is the process of disposing of data for information that would be invisible to the viewer. However, too CDV significantly distort the output. data is a high level of CDV, most will be discarded.Dispose is too much, and the distortion is very surprising.
CDV is a compromise between file size and image quality. CDV is working on neighborhoods called pixel macro block. The CDV only the changes in these blocks. This method works well if the video is primarily static images as text.
In a basketball game when Kobe gets to the basket, the more pixels change from one image to another. If this happens, the video compression algorithm work harder. The image qualityafter compression depends on the complexity and predictability of the images.
CDV is the most common standards are written by the Moving Picture Experts Group (MPEG). The application of CDV is an intensive on-screen computer, but decompression (release of CDV) to the MPEG video data is much less difficult. A C-Cube real-time MPEG-1 video encoder with 8 custom processor chip sold for $ 120,000.
MPEG standards are heard by anyone. Several companies and researchers haveMPEG patents, but do not pay a license fee to use the MPEG technology.
DVD and Blu-ray have CDV are used in the process of burning (Blu-ray Disc has sufficient capacity that the CDV is not aggressive, so do not add significant distortion). algorithms are high-definition video with little CDV for video post-production work, but still uses this huge file, and therefore only rarely for distributing video.
There are several standard MPEGused, but only three are commonly used for distribution of commercial films:
MPEG-1
MPEG-1 was the first widespread video (and audio) standard CDV. MP3 is short for "MPEG-1 Audio Layer 3". MPEG-1 supports a screen resolution of 352 x 240 at 30 fps (frames per second). And 'the standard for CDV motion picture (and sound). This rule has found its roots in the CD-ROM video applications and is popular for video on the Internet (. MpgFiles).
MPEG-2
MPEG-2 video resolutions supported by 720 x 480 1280 x 720 at 60 FPS. MPEG-2 is capable of both high-definition TV and HDTV standard. The MPEG-2 standard is also used to store data on a DVD. This is the algorithm of DirecTV Dish Network uses.
MPEG-2 is the standard that is based on boxes, digital television set-top DVD and CDV. It 's based on MPEG-1, but modified for use by digital television. Various algorithms have beendeveloped and integrated into the standard. MPEG-2 is ideal for HDTV resolution and bit rate prices. With this technique, video data CDV 15 to 25 times while still compressed image quality to be a high value.
MPEG-4
This standard is the future standard VCD, which provides HDTV services will almost certainly be the majority. These include AT & T, DirecTV and Dish Network. A number of cable operatorsMPEG-4 has also launched studies. This standard was originally designed for the Internet. individual objects within a scene are recorded separately. This is very efficient.
The transition to MPEG-4 is the satellite companies are not designed to improve image quality, but because this algorithm is much more efficient. An-2-band channel of HDTV MPEG uses six standard definition TV channels, MPEG-4 HD channels only consume the bandwidth of the three standard-definitionTV channels. MPEG-4 uses half the bandwidth of MPEG-2, and so the service provider can offer twice the number of channels.
OpenCable Application Platform (OCAP)
Consumers can now purchase their own cable box / DVR combo at the electronics retailer. OCAP is to provide a way for cable operators and other service providers for interactive services, such as a PC. This allows American Idol voters cast their vote with the remote control for their employmentTV.
Consumers want their HDTV, and service providers that offer the program to flourish. MPEG-4 is the best option and cheaper for cable operators and other service providers.
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