The primary concern when using optical storage media to store data, is to ensure that the result will be a readable disc, over a very long period of time. Readability then, depends on the reading drive, which is influenced by the resultant writing quality produced on the disc, which is in turn directly related to the recorder used for burning and the optical medium itself.

The Optical Storage industry has defined specific parameters that reflect the quality of a recorded disc. These are actual measurements of electric signals that represent the overall condition of a disc and, when looked at as a whole, provide a complete picture of the recording quality. These signals provide information about the physical condition of a disc and the integrity of the digital data, as they are stored on the disc and retrieved by the player.

Quality testing has been practiced for decades now, first for CD and later for DVD media. Currently, with the High-Definition formats already available on the market, there is a further and growing need for accurate testing. Moreover, the fact that the next-generation formats are squeezing even more data onto 12cm media using various techniques, makes it easy to understand why measuring the quality of the recorded data is more complicated when compared to CD and DVD.

In the following pages, we present some writing quality measurements of BD-R (Blu-Ray Recordable) and BD-RE (Blu-Ray Re-Rewritable) media. The discs were burned with some of the most popular Blu-Ray recorders for PCs, currently available on the market. In cooperation with DaTARIUS, the leader in quality optimization, measurements and evaluation of optical storage media, CDRInfo presents a brief explanation of the basic signals related to the quality of a Blu-Ray disc, and of course, the first real-life measurements on sample discs.

In the first pages, we tried to summarize the physical characteristics of the Blu-Ray disc format, the basics of the data encoding and error correction used, as well as an explanation of the basic signals that are essential for the evaluation of the writing quality of a Blu-Ray disc. Moving on, we provide information about the testing procedure, and of course the results.

At this point, we should mention that some discs were measured a second time. After initial measurements, a number of discs produced uncharacteristically poor results and we were keen to find out why. As we have done on similar occasions in the past when testing DVD media, we decided to run a second pass to confirm the results. Before doing the second pass, a random selection of discs was taken and cleaned using air spray and special tissues. The results after this procedure are quite revealing as will be seen in the ensuing pages.