Sony DCR-DVD200 DVD Handycam Technology Handbook - Page 21

GLOSSARY ❏ Laser The DVD Handycam recording system uses a shortwavelength red semiconductor laser device to record data. This device passes current to a semiconductor and emits a strong beam of light. Gallium arsenic is used to generate the short-wavelength red laser beam that reads digital data on a DVD disc. ❏ Linear PCM Recording Linear PCM (Pulse Code Modulation) is an audio system that converts analog to digital signals without compression; it is used primarily in high fidelity music recording. DVD Handycam camcorders do not use Linear PCM recording. ❏ MPEG MPEG (Moving Pictures Experts Group) is an international group that establishes industry-wide standards for digital signal compression. These standards are known as MPEG 1, MPEG 2, MPEG 4, etc. ❏ MPEG 2 MPEG 2 is a digital standard for demanding video applications. It offers high quality images with data compression that reduces the amount of data that must be processed. Rather than processing complete video frames, the MPEG 2 system processes only the differences between adjacent frames. ❏ MP@ML The MPEG 2 standard allows various parameter setups for picture formats and coding modes. MP@ML (Main Profile at Main Level) is the parameter setup adopted for DVD-Video and DVD-VR (Video Recording) applications. "Profile" refers to the combination of functions provided; "Level" refers to the level of resolution and frame rate. ❏ Numerical Aperture Numerical Aperture (NA) value determines the performance of an object lens; the larger the value, the more data can be written at any one time. ❏ Object Lens This lens performs two tasks: first, focusing the laser onto the disc surface; second, collecting the reflected laser light and concentrating it on the photodiode detector. The performance of the object lens largely depends on the value of its numerical aperture (NA). ❏ Pit Pits describe the microscopic hollows within the surface of a DVD-ROM or CD-ROM disc. Data is read in a spiral motion and is determined by the length and number of pits that occur. The discs used by DVD Handycam camcorders do not have pits; instead, their data is carried by changes in reflection on the disc's surface. ❏ Playlist The function that arranges movie scenes and still images on a DVD disc. Playlists can be set up for editing and playback purposes; recorded scenes and still images are not changed by being put in playlist order. ❏ Track A data-recording field in the shape of a spiral or concentric circle. CD and DVD tracks have a spiral structure; floppy disc and hard disc tracks are concentric. The distance between adjacent tracks is called "track pitch." ❏ Variable Bit Rate Variable Bit Rate (VBR) changes its data conversion process depending on the amount of movement (or "dynamics") in a given scene; its purpose is to reduce data requirements to a minimum while maintaining high image quality. ❏ Visual Index A DVD Handycam function that displays movie scenes and still images as "thumbnail" images on a multi-image screen, making it easy to find a specific scene or image for playback. ❏ Optical Pickup This device combines a short wavelength semiconductor red laser, a pair of 45-degree mirrors, an object lens and a photodiode. In the DVD Handycam system, light emitted from the laser is bent at a 45-degree angle, passes through the object lens, reflects off the surface of the DVD disc, is concentrated by the object lens and detected by the photodiode. • Manufactured under license from Dolby Laboratories. "Dolby" and the double-D symbol are trademarks of Dolby Laboratories. • Microsoft and Windows are trademarks or registered trademarks of Microsoft Corporation in the United States and / or other countries. • PlayStation is registered trademarks of Sony Computer Entertainment Inc. • All other product names mentioned herein may be the trademarks or registered trademarks of their respective companies. Furthermore, "™" and "®" are not mentioned in each case in this manual. 21 DVD Handycam TECHNOLOGY HANDBOOK