Here is an extended explanation on the basic concepts of recording DVD-video, CD-R video and Video CDs.
Been to a video store lately? If so, youve probably noticed that you can rent movies on something other than good-old VHS tape. More and more releases are now available on DVD, a shiny disc that holds moving images and sounds in a digital format. DVD delivers excellent audio and video quality plus the potential for interactivity: viewer-selectable camera angles, alternate edits, multiple languages and much more. Intrigued? As a videographer, you should be!
Unfortunately, due to the high cost of hardware putting your own videos onto DVD has been an unaffordable dream for most. But this is rapidly changing-hardware prices are dropping to the point where burning your own DVD (or CD-ROM or Video CD) isnt outrageously expensive. What it still is, though, is confusing. Many videographers have tried to burn their own video discs but found themselves lost in a maze of acronyms, technical jargon and fast-moving standards.
Sound familiar? If so, youve come to the right place. Well do our best to explain the basic concepts of recording to DVD-Video, CD-R video and Video CD discs.(See accompanying sidebar for an explanation of the different acronyms.)
The Big Picture
When you boil it all down, there are two main issues at work when it comes to recording video onto a disc. First, you have the physical disc format itself. There are just two to consider-CD and DVD. Both use tiny pits in a reflective medium to represent digital data, but the newer DVD technology packs much more data on the disc. You can think of both as simple storage devices that store any type of data without bias.
The bigger issue is what type of data a given disc holds and how that data is structured. DVD-Video, for example, is simply a DVD disc with MPEG-2 video, audio and a file structure that makes sense to a DVD player. A Video CDs medium is just like that of an audio CD, but the video and audio files are saved in the specific format a Video CD player expects.
Keep in mind that CD and DVD can store any type of information, not just the latest DVD Video movie or Microsoft Office 2004. This means you can use a CD or DVD to hold digital video and audio thats not formatted for a specific hardware device (such as a DVD player). Since this is sort of like a cross between the strictly data and strictly video applications, youd use a computer to read and play back these files. Its just good to remember that DVD Video, for example, represents just one way to store digital video and audio on a DVD.
If youre reading between the lines, youve probably already figured out the good news-computers that have a CD-R drive are physically capable of writing a Video CD, and those with a DVD-R drive can write a DVD Video disc. When it comes to burning 1s and 0s into that shiny silver disc, youre already equipped.
But as we mentioned above, the physical format of the type of dics you use is only half of the equation. The other half is getting your video and audio files in the correct format-and in the right place-for playback in a stand-alone player. This is where specific software comes into play to encode and author.
Blend, Pour, Bake
Whether youre making just one copy for yourself or creating a master to send off for duplication, the DVD and CD-ROM creation process is essentially the same: digitize, encode, author and burn. (See figure one for a graphic overview of these steps.)
The encoding step converts digital video and audio files from one format to another, usually reducing their size dramatically along the way. Encoding for a DVD Video, for example, involves compressing video files with the MPEG-2 standard. The software then encodes audio files into any of several formats (surround, 5.1 surround, stereo, etc.) recognized by DVD players. The encoding process is similar for a Video CD, but software uses lower-quality MPEG-1 compression for the video and audio.
At the encoding stage, DVD makers have numerous parameters at their disposal for controlling image and sound quality, as well as the amount of video that will fit on the disc. Good DVD encoding fits the required amount of video on the disc at the highest-possible quality, with no wasted space. For a major motion picture, this might equate to roughly two hours of video. Drop the quality down to the VHS level, and you could fit 10 or more hours of video on the smallest-capacity DVD. Be forewarned: depending on quality settings, the software you use and the speed of your computer, encoding MPEG-2 can be a lengthy process.
Authoring software then takes the encoded video and audio files and formats them according to their intended purpose. For DVD, the encoding software records various special codes required for correct playback, as well as such optional goodies as chapter points, navigational aids, menus and overlayed graphics. Because capabilities of the Video CD arent as advanced, Video CD authoring software is simpler and less costly than DVD authoring software. Some software packages combine encoding and authoring into one step.
The final step is to actually burn the audio, video and other special files to a blank DVD-R or CD-R disc (about $30 and $1 respectively). Everything is just a series of numbers at this point, and the recorder will lay these bits onto the disc as fast as the burner hardware (or the operator) will allow. Since DVD and CD-R burners range in speed from 2x to 12x and beyond (CD-R), the process doesnt happen in real time. If your hardware is very fast, for example, you may be able to burn a full 74-minute Video CD in about 5 minutes.
Burning For You
Is everything rosy in the world of home-cooked DVDs? Not entirely. DVD-R drives record permanently on a disc, offer the best compatibility with home DVD players, but still cost several thousands of dollars. Most professional DVD authors use DVD-R drives.
Rewritable DVD drives have dipped below the $1,000 mark, and may be available for less than $500 by the time you read this. Unfortunately, the rewriteable DVD market is in the middle of a bitter format war. Three competing standards (DVD-RW, DVD+RW and DVD-RAM) are available and each has its advantages and disadvantages. Compatibility with existing home DVD Video drives and computer DVD-ROM drives is one of the hottest topics, so be sure to check for late-breaking news before you purchase a drive (see Web Lines sidebar).
Folks wanting to burn their own Video CDs have it easy. They may already have everything they need, provided their CD-R bundle included the correct software.
Keeping up with digital video is all about learning new technology and new techniques and the latest trend away from tape and toward DVD is no exception. Someday soon, a silver disc may be the final destination for all your video projects.
When that day comes, youll be ready to burn your own with the best.