Nero CD-DVD Speed: Disk Quality Test
As the final step in this test session, I will burn a few DVD discs of various formats in the tested drive and will check their quality. Of course, I can’t check the drive with all existing media, in all possible modes and at all supported speeds, but this test is anyway indicative of the burn quality the optical drive provides. I used Nero Burning Rom to record all the discs at their maximum rated speed. The quality of the recorded discs was verified in a Sony DW-G120A drive with MYR4 firmware. We use it to achieve comparable results from different test sessions, and this drive offers good hardware characteristics for that purpose.
As for the disc quality criteria, the ECMA standards for DVD-R/RW and DVD+R/RW media say that the total number of PI errors in 8 subsequent ECC blocks should not exceed 280. This is the first limiting value I will base my judgments upon. Then, an ECC block should not contain more than four irrecoverable PI errors (an irrecoverable PI error is referred to as PI Failure by the CD-DVD Speed utility).
DVD discs that have no more than 280 PI errors per eight ECC blocks and 4 PI failures per one ECC block should be considered acceptable-quality media. Besides these criteria, you should also note how the errors are distributed along the surface of the disc. It is the worst situation when the errors exceed the acceptable limit on the entire surface, but single and short-time spikes of errors are less dangerous.
Of course, the more discs are recorded with high quality, the better for the tested drive, but you should keep it in mind that besides the hardware properties of the drive, its firmware version has a big effect on the burn quality, too. Some problems can be solved by the manufacturer with firmware updates.
Digitex DVD+R 16x
The quality of this disc doesn’t meet the ECMA requirements. The maximum of PI Errors is all right, but the allowable maximum of PI Failures is exceeded in several places here, although without any regularity. The total of errors is not large.
TDK DVD+R 16x
If I were formalistic, I would find fault with the Digitex DVD+R as there is one place in the diagram where the maximum of PI Failures is higher than permitted by ECMA. This is not a big problem, though, so the overall burn quality of this disc should be considered as very good.
Philips DVD+R 16x
Certain problems can be seen with this Philips DVD+R disc. The level of PI Failures is higher than normal, especially on the final part of the disc. The disc meets the ECMA requirements in terms of maximum allowable level of PI Errors, yet the level of such errors is high on this disc.