Frequently Asked Questions About Quality

Please contact Media Sciences if your questions are not answered on these pages.

How are CD and DVD specs related to sound and picture quality?

This relationship is highly dependent on the player. Rapid CD and DVD drive obsolence and the lack of standards for drives make it impossible to predict which media flaws will or will not result in playability problems. Only conformance of the disc to all relevant standards will assure interchange and longevity.

Many important tests evaluate how the disc and drive interact, but cannot predict playability because read drive performance is not specified. If a good disc fails to play, then it is the fault of the drive. If a bad disc plays, then it indicates a forgiving drive and pending disaster in other drives. Data streaming may overlook certain defects, but retries, applications that require seeks, or start/stop playback may be sensitive to the same defects.

The human ear and eye are remarkably forgiving. Golden ears or platinum eyes may detect objectionable sound or picture flaws that most of us would not. Some of these flaws result from nonconformance with media standards. Other flaws may result from conditions that were not relevant when disc standards were issued.

One example is new high speed risks created by drive speeds in excess of 40X. These risks were not anticipated in standards that were written long before such speeds were attained. High speed problems such as unbalance and cracking or shattering arise from both media and drive related quality issues that were always present but were not significant at lower speeds.

Comprehensive testing by an experienced laboratory must evaluate both new quality issues as well as conformance to media standards. Users should acquire a full understanding of the technology and quality requirements, and must be actively involved in an effective quality program if a high level of confidence in interchange is to be attained.