DVD Recording

What's DVD Recording?
Worldwide DVD player market
Since its introduction in 1996, DVD-Video fast became the new world standard for movie and concert video enjoyment, with extremely high quality picture and sound reproduction. Not only have DVD players become commonplace, DVD drives are increasingly employed in computers, game devices and other electronic equipment. DVD is truly a versatile new storage medium across a wide spectrum of applications.

Naturally, the time has come for writable DVD. High picture and sound quality combine with many versatile playback functions to make this the media of choice. The dream of high-quality digital disc recording in the home, not only for audio/video entertainment, but also for computer storage, has now become a reality as a media suitable for the era of broadband communications.

The total number of DVD playback units, including PCs and game equipment with DVD drives, is expected to increase greatly in the near future.

Writable DVD comes in several different formats. There are several different writable DVD format specifications.

DVD-R, DVD+RW, DVD+R, DVD-RW, DVD-RAM
Let's take a look at the common features and differences of each.

Writable DVD has these superior features.

Storage and playback of digitally recorded video and audio with superior image and sound quality.

Non-contact optical reading system is impervious to wear during repeated playback,and is highly resistant to the effects of dirt and scratches, for superior storage characteristics.

Quick random access to image and sound without the need for cueing or rewinding.

Up to 4.7 GB of data can be recorded on a CD-sized 12 cm optical disc. Digital recording with high image and sound quality.

Random access for superior operation.

Digital recording of both image and sound.

Just like DVD-Video, writable DVD digitally records video using the MPEG-2 format, and digitally records audio using Dolby Digital and other formats. This assures extremely high quality video and audio recording, while also ensuring playback compatibility on conventional DVD players.

A DVD holds seven times as much data as a CD. One side of a DVD can hold up to 4.7 GB, about seven times a CD holds. This high data capacity enables longer recording of video and audio.

12 cm discs are easy to handle, easy to store. DVDs are the same size as CDs, just 12 cm and only 1.2 mm thick. Even a large video collection takes up very little space. Plus, they're easy to carry and send.

The relationship between image quality and recording time. Recording time on a given disc varies according to the data transmission rate. If the rate is high, image quality is better, but recording time is shorter. If the rate is lowered, recording time is longer, but at the expense of image quality. Moreover, even with the same recording time, image quality can change depending upon the format for audio recording. By varying the transmission rate, priority can be placed either on image quality or on longer recording time.

Titles and Chapters in Writable DVD
In DVD, content is organized by titles and chapters. In read-only DVD-Video software, one movie is generally considered one title, and within the title there are several chapters which can be accessed through the menu. In writable DVD, one recording is saved as one title, and within that title different chapters can be specified. Using this chapter and title data, various playback and editing functions can be performed from the menu.

What is the difference between DVD-R and DVD+R?
While DVD-R and DVD+R both have the same basic construction as DVD-ROM, there are differences in their rotational control systems and data recording positions.

What are the differences between DVD-RW, DVD+RW and DVD-RAM?
While DVD-RW and DVD+RW both have the same basic construction and performance of DVD-ROM, there are differences in the way their disc rotational control systems and data recording positions are configured. DVD-RAM uses a special land and groove recording configuration and specification which enables data to be rewritten up to 100,000 times, compared to 1,000 times for DVD-RW and DVD+RW.

How Write-once and Rewritable DVDs work.
During DVD recording, a powerful laser beam, stronger than that used for playback, heats up the recording material, changing it to represent the data. Write-once DVDs use chemical change, while rewritable DVDs make use of phase change.

In write-once recording, the organic dye is chemically changed.
During recording, a powerful laser beam is focused on the organic dye recording material, and the heat from the laser changes the chemical structure of the dye. During playback, the playback laser can sense which parts of the dye have been changed by heat and which haven't. Through this process the [0] and [1] of a digital signal can be represented. However, changes in the dye structure are permanent, so the disc cannot be rewritten.

In rewritable recording, the phase of the recording material is changed The recording material used is in crystalline form before recording. When it is heated by the powerful laser, it becomes amorphous and loses its crystalline structure. However, weaker laser light can be used to slowly heat it to return it to its original crystalline form. In this way, the disc can be rewritten over and over.