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Compression Schemes used with BUDs? http://www.fta-n-more.net/forum/viewtopic.php?f=13&t=303 |
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Author: | Digi [ Thu Jul 08, 2010 3:28 pm ] |
Post subject: | Compression Schemes used with BUDs? |
Digital compression allows for more than one video and/or audio channel per satellite transponder. 1. DigiCipher II - DigiCipher II (DC2) is a digital encoding and encryption format developed by General Instruments (now part of Motorola) that is used for many American digital TVRO transmissions. In order to view DC2 channels, a special receiver called 4DTV is required. DC2 is a proprietary standard based upon MPEG-2. DC2 technology can be licensed to other companies, but no other companies have requested a license. Only Motorola manufactures 4DTV receivers. Those made for consumer BUD use cost around $400-$800 suggested retail, but are typically available at discounts that at times can be quite deep. 2. DVB/MPEG-2 - MPEG-2 is a general encoding scheme used for many differing digital technologies; DVB, which stands for Digital Video Broadcasting, is the satellite television-specific variety of the MPEG-2 standard. This is not so much a competing digital standard as it is an OPEN standard. This standard is used in most of the world outside of the U.S. for digital TVRO broadcasts. Many international and non-traditional programming is found using DVB/MPEG-2. Many U.S. DVB feeds are free to air and are receivable with a DVB/MPEG-2 FTA digital satellite receiver. Channels using this standard may or may not choose to stay free-to-air indefinitely; once a network disappears, it may or may not be gone forever to consumer TVRO viewers. A Word About 4:2:2 Screen Pixel Ratio Most DVB/MPEG-2 receivers receive what is called 4:2:0 screen ratio for picture resolution. But certain DVB/MPEG-2 channels, usually network and/or studio feeds, use what is called 4:2:2 screen ratio. This involves the ratio of video data to vertical pixel and horizontal pixel color. 4:2:2 is NOT part of the standard DVB specifications but is used mainly by studios that need better picture quality than standard DVB offers. This is the standard currently used for in-the-clear reception of NBC, as well as Warner Brothers and Fox network feeds. Most consumer FTA receivers cannot receive signals with the 4:2:2 ratio; a more expensive receiver is required. Note that 4:2:2 is NOT a type of encryption; however, like certain types of encryption, it does force the TVRO viewer to make certain considerations when purchasing receiving equipment. |
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