relative to an audio CD (Compact Disk)
|Blu-Ray||25 GB/54 GB||1||high capacity. Used for High Definition movies. Uses a blue laser to read them. The dual layer disks hold 54 GB. That is equivalent to 20 hours of standard video. Heavily encrypted to prevent copying. This is the format Microsoft, Sony, Lion’s Gate, MGM, Columbia, Fox, Disney and Wal-Mart are backing. Blu-Ray DVDs allow interactivity controlled by Java programs, though I have not heard the details of how this is supposed to work. The scheme is called BD-J (Blu-ray Disc Java). They come in R and RW versions. You can buy pre-recorded Blu Ray DVDs with movies on them. Players can take ridiculously long time to load. For example the Pioneer BDP-Lx71 takes almost 2 minutes.||each. Last revised/verified: 2009-03-20|
|HD DVD||15 GB/30 GB||1||Paramount supports only this format. Heavily encrypted to prevent copying. Developed by Toshiba and NEC (Nippon Electric Corporation). You buy them pre-recorded with movies in encrypted format. You don’t usually record your own material on them. Only proprietary hardware that prevents copying can read them. Provides sufficient resolution for full HDTV (High Definition Television). Like Blu-ray, it uses a short wavelength blue laser. Players cost half as much as Blu-ray, and is more reliable, yet oddly it lost the format wars. On 2008-02-18 Toshiba threw in the towel and discontinued manufacturing players and discs. I think the Blu-Ray people won by repeatedly telling a small lie, that you needed Blu-Ray to get high definition. Naive users thought Blu-Ray was the only choice for HD. I think also Blu-Ray was a more distinctive name. HDDVD did not sound like a distinct product.|
|DVD-Video, DVD5/DVD9||4.7 GB/9.2 GB||?||Time-Warner, Disney, MGM/UA etc. backing. read only. Created by mass duplication. The dual layer disks hold 9.2 GB.||Blanks are not generally available since is illegal to duplicate movies.|
|DVD-R||4.7 GB||8-48||write once||each. Last revised/verified: 2009-03-20|
|DVD-RW||4.7 GB||2.4||write many times||each. Last revised/verified: 2009-03-20|
|DVD+R||was 3.0 GB/side, now 4.7 per side. With double layer 8.5.||18||compatible with DVD-RAM. writableonce. dvd+r has a slightly more robust tracking system than DVD-R. My 16× drive writes 11.4 megabytes a second, considerably faster than CDW (Compact Disc — Writeable) drive.||each. Last revised/verified: 2009-03-20|
|DVD+RW||was 3.0 GB/side, now 4.7 per side. With double layer 8.5.||8||compatible with DVD-RAM. rewritable.||each. Last revised/verified: 2009-03-20|
|DivX||n/a||?||scheme to allow game or video rental||Not available to the public.|
|DVD-RAM||2.6 GB/side||?||used in Hitachi camcorders||each. Last revised/verified: 2009-03-20|
The rotation speed is not really the statistic you want. You want the transfer rate in megabytes per second. However, those numbers were not readily available. The main thing you can learn from these numbers in that RW disks are much slower than R disks to record. Further, you need an extra erase pass.
You would think DVDs would play from the outside in, like vinyl LPs (Long Play recordings) but they start at the centre and work out. This seems odd given the outer tracks are longer than the inner. The advantage of this is it often leaves the outer tracks unused which are often smeared with fingerprints by people failing to pick up the DVDs properly.
Use a red Sharpie fine tip permanent marker to write the password/serial number/key on the top side of the DVD where you can’t lose it. Don’t apply any sort of sticky label since it may come off inside the drive, unless it is specially designed for DVD s.
DVD drives compete on cost, so the quality has dropped over the years. You are lucky if they survive a year. They drive you crazy popping open when you don’t want them to and closing unexpectedly when you want them to stay open, and refusing to open when you press the button. You give them a command, and like a reluctant child, they procrastinate far longer than reasonable reacting to it. I don’t know if the fault lies with W7-32/W7-64 the device driver or the disk hardware. There is no brand I can recommend. Paying a lot of money does not seem to help. Repairing them is usually almost as expensive as the cost of a new drive. They are full of mechanical parts, belts and Rube Goldberg contraptionry. Perhaps some day someone will invent a drive that does not spin the disc, just optically scans it.
Typically a drive will be rated 18X DVD-ROM 48X CD-ROM which means it spins 18 times faster than a CD in your stereo player when reading a DVD and 48 times faster when reading a CD The speeds for burning a DVD/CD will be slower, typically 6X. To get reliable burns, you often have to slow the drive down. LiteOn makes a drive that claims in can burn at 24X, but since the blanks are rated at a max of 16X, you will never go above 16X.
If you do a lot of CD or DVD copying, you might want to get one read-only DVD drive and one DVD burner drive. For extra cost, you can also burn Blu-Ray discs.
Entertainment DVDs usually have silence for the first minute or two. Instead they should start with a sound check of standard volume, starting with a left then right ping. That way you can ensure have an appropriate volume adjusted before you sit down to watch. Further the remove that controls the DVD should also control the volume. With digital interconnections, you would not need to deal with the combined effects of the volume settings of player and amp.
DVDs take an inordinate amount of time to eject or to start playing. I can’s account for it with spin-up spin-down. It must be something else chewing up the time. What is it?
available on the web at:
optional Replicator mirror
Please email your feedback for publication, letters to the editor, errors, omissions, typos, formatting errors, ambiguities, unclear wording, broken/redirected link reports, suggestions to improve this page or comments to Roedy Green : . If you want your message, your name or email kept confidential, not considered for public posting, please explicitly specify that. Unless you state otherwise, I will treat your message as a letter to the editor that I may or may not publish in the feedback section. After that, it will be too late to retract it. If you disagree with something I said, especially when sending an ad-hominem attack, a rant composed mainly of obscenities or a death threat, please quote the offending passage and cite the web page where you found it, tell me why you think it is wrong, and, if possible, provide some supporting evidence. I can’t very well fix erroneous or ambiguous text if I can’t find it.
|no blog for this page||Canadian
Your face IP:[184.108.40.206]
|Feedback||You are visitor number 17,258.|