- — 18 October, 2005 11:16
- DVD vs. CD
- Capacity confusion
- Questions to ask yourself
- Comparing DVD standards
- Who supports which standard
- Other Considerations
Double the layers, double the capacity
As we've mentioned, double-layer technology brings big benefits to DVD storage. About 4GB worth.
The only writers and media to support this technology so far have come from the +R camp. The write-once discs hold 8.5GB of data, but may only be written to at speeds much slower than their single-side counterparts. Double-layer compatibility is usually indicated by the letters "DL" following the drive or disc type. The price tags for these advanced drives and media may also be a little longer, too.
Double-layer technology is not as recent a development as it may seem. Commercial DVD-ROM discs, such as those used to distribute movies, have long used double-layer technology. Therefore, any double-layer disc you record should be able to be read by most DVD-ROM players.
DVD writer speeds
The speed with which DVD writers write to media varies, and depends on both the standard and the product you select. You will need to check the box of the specific product for this information. Currently 16x is the average speed for writing to any type of write-once media, while 4x is the most average rewrite speed. Either disc type can be read at 12x.
According to PC World tests, DVD+RW writers maintain the fastest rewrite times when compared to the other standards, while DVD-RAM writers record the slowest speeds for writing to disc.
PC World tests were based on how long it took to copy 1.45GB of data from the hard drive to a DVD disc. Two samples of DVD+RW writers took between nine and 12 minutes to copy this amount of information to DVD+RW discs. DVD-RW writers ran the second best times, taking around 11 minutes to copy the same amount of information onto DVD-R discs. However, when writing to its own DVD-RW media, PC World tests showed one DVD-RW writer to take over 20 minutes to perform the same task.
The DVD-RAM writer was the slowest performer, taking twice as long as its counterparts to write 1.45GB of data to both DVD-RAM and DVD-R media.
DVD writers vary in price depending on the quality of the equipment and whether it is an internal or external drive. Drive prices start around $100 (internal) and $200 (external). While there isn't a large price difference between the DVD+RW, DVD-RW and DVD-RAM drives, there are differences in the cost of media used by each, which may affect your choice.
DVD-RAM: DVD-RAM discs come in two types of cartridges. Type 1 is a non-removable disc, and Type 2 a slightly more expensive cartridge from which users can remove the internal disc. A total of four sizes are available across these two forms: 2.6GB, 4.7GB, 5.2GB and 9.4GB. DVD-RAM media are easily the most expensive of the standards, with prices starting at just over $10 a disc.
DVD-RW: DVD-RW media tend to be significantly cheaper than their RAM competitors. DVD-RW media come in two types: Authoring, for professional use, and General, a less-expensive consumer media.
DVD+RW discs, like DVD-RW, are available in 4.7GB format for about the same price.
DVD-R and DVD+R: The most popular of the media types are also the cheapest. There are two types of -R disc available: data (for PC use and one-time video recording only) and authoring discs, designed to be used to record video, audio and multimedia imaging for professional content developers and software producers. DVD+R media are sold as one general use type.
You shouldn't pay more than a couple of dollars for one -R or +R general use disc. Once again, these disc types hold 4.7GB and are produced by a range of manufacturers.
Mt Rainier support
Mt. Rainier, also known as EasyWrite, allows an optical disc to be used just like a floppy disk. That is, being able to read from and write to the disc without special burning software. It differs from traditional packet writing software in that it performs most of the tasks (such as background formatting and handling defect management) in the hardware of the drive itself.
Few drives will have Mt Rainier support built-in, until the technology is included as a standard part of the next Windows release, Vista (formerly code-named Longhorn). Mt Rainier is available for DVD+RW only.
Authoring & editing software
Whether you're writing to the + or - standard, there's a good chance you'll be able to edit your favourite digital camera footage on the PC, burn it to disc, and then view it in your DVD player -- complete with interactive menus.
To do this, you need DVD authoring software. This is often sold with DVD writers.
Authoring software not only provides the tools to edit your video footage, it also creates the indexing system at the front of the disc, which the player needs in order to read the information stored on it. Without this indexing system, the player will most likely be unable to read the information on the disc. In short, authoring software gets your finished video (or data) onto disc.
Authoring software also has the ability to encode your video footage in either lower or higher quality (MPEG-1 or MPEG-2) formats. Professional authoring packages take this technology much farther, and offer the ability to create multiple soundtracks and camera angles, add subtitles and surround sound. There are many DVD editing software programs available, from entry-level products to professional editing tools.
The options aren't so bright in copying commercial DVD discs with a DVD writer. You can make copies of commercial DVDs, so long as they don't have copy protection and you've got sufficient space on your disc (most DVD videos use around 8.4GB on a dual-layer disc; more than the amount of space offered on most general purpose DVD media). Remember though, duplicating copy-protected commercial DVDs is usually illegal.
A buffer is a data area shared by hardware devices or program processes that operate at different speeds or with different sets of priorities. The buffer allows each device or process to operate without being held up by the other.
Basically, the rule of thumb with buffer size is the bigger the better. The buffer size in most DVD writers is commonly 2MB.