Duet CD-R2-U2 slim CD-RW/DVD combo - Page 5

DVD Error Correction Tests

In the following tests we examined the DVD error correction capabilities of the Duet LSC-24081. For the tests we used CDVD Benchmark v1.21 and Nero CDSpeed . The reference test media comes from ALMEDIO.

- Single Layer media

ABEX TDR-821

This is a single sided, single layer DVD-ROM with a 4.7GB capacity, in which there are scratches with dimensions ranging from 0.4 to 3.0 mm. The following transfer rate picture comes from CDVD Benchmark v1.21.

The Duet seems to have no problem finishing the reading task with no errors. The drive lowered the reading speed to an average of 5x when it reached the 500,000th sector, according to the software. The reading speed was kept at 5x until the end of the reading process. No read errors occurred.

ABEX TDR-825

This is also a single sided, single layer DVD-ROM with a 4.7GB capacity. The data structure of the disc is exactly the same as of the TDR-821, with the difference being that there are no scratches on it, but defected areas with dimensions ranging from 0.5 to 1.1 mm. There are also fingerprints sized from 65 to 75 micro meters.

The drive did not have any problems to read the disc contents. The yellow dots correspond to the current speed in each area of the disc. The CDVD software reads each sector multiple times and decides the average value for the main graph. No read errors were reported.

- Dual Layer media

ABEX TDR-841

This is a 8.5GB dual layer, single sided DVD-ROM disc with artificial scratches with dimensions ranging from 0.4 to 3.0mm, in both layers.

Again no read errors occurred, but looking at the graph you can see that the drive read each sector in many different speeds (yellow dots). This means that the task was not very easy for the drive but the result is adequate.

ABEX TDR-845

The disc is a single sided, dual layer DVD-ROM disc with a capacity of 8.5GB. The only difference between the TDR-845 and the TDR-841 is that the first includes defected areas and fingerprints. The dimensions of the defected areas rang from 0.5 to 1.1 mm and the fingerprints are sized between 65 to 75 micro meters.

As in the corresponding test with the ABEX TDR-825 (defected single layer DVD-ROM), the drive had no problems to finish the task successfully. The reading speed was again set to 5x by reaching the middle of the capacity of each layer.

ABEX TDV-541

The TDV-541 is a single sided, dual layer DVD-VIDEO disc, with a capacity of 8.5GB. The disc is based upon the TDV-540 series which is designed for inspection and adjustment of DVD-VIDEO players. The discs check the layer switch operation from layer 0 to layer 1 and also include test pictures and test signals for DVD sound files. The current TDV-541 checks also the error correction capabilities of the drive and includes scratches from 0.4 to 3.0 mm.

The drive gave a 4.36x average reading speed for the DVD-Video format. The scratched areas forced the drive to slow down momentarily, but it seems that there were no reading problems.

ABEX TDV-545

The TDV-545 disc is based on the TDV-540 series. It is a single sided, dual layer DVD-VIDEO disc with a capacity of 8.5GB. The TDV-545 includes artificial black dots on the data surface, sized from 0.4 to 1.0 mm. It has also 65 - 75 micro meters fingerprints on the reading surface.

Black dots and fingerprints were not a problem for the drive. The test was successful, at a 4.42x average speed .