DVD-ROM Roundup Vol.4 - Page 6

DVD Error Correction Tests

In the following tests we examine the DVD reading capabilities of the drives with scratched / defective DVD media. For the tests we used CDVD Benchmark and Nero CDSpeed. The reference test media came from ALMEDIO.

- Single Layer media

ABEX TDR-821

This is a single sided, single layer DVD-ROM with 4.7GB capacity, and its surface has an artificial scratch of dimensions varying from 0.4 to 3.0 mm.

The following transfer rate screenshots come from the CDVD Benchmark v1.21 transfer rate test.

This disc was not a problem for any of the drives. We consider that the ASUS' reading graph was about as smooth as it gets.

ABEX TDR-825

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

There are also fingerprints sized between 65 and 75 micrometers.

The performance was again good for all the drives. However, the Samsung and LiteOn drives had a few momentary drops, especially over the defective area on the disc. On the other hand, the ASUS again produced a near perfect line.

- Dual Layer media

ABEX TDR-841

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

All drives managed to read the defective areas on the disc without any problems. There are also very few speed fluctuations (random yellow dots), indicating how effortlessly the drives read this disc.

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 defective areas and fingerprints. The dimensions of the defective areas range from 0.5 to 1.1 mm and the fingerprints are sized from 65 to 75 micrometers.

The ASUS and LiteOn drives showed very good performance. The Samsung's reading graph shows a reading error (red dot) over the middle of the first defective region on the first layer of the disc which is not good. We repeated the reading but the results were the same for the Samsung drive.

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 disc checks the layer switch operation from layer 0 to layer 1 and also includes test pictures and test signals for DVD sound files.

The current TDV-541 also checks the error correcting capabilities of the drive and includes scratches from 0.4 to 3.0 mm.

The reading process finished successfully for all drives. The region just after the layer switch seemed to be difficult for both the ASUS and Samsung drives, where both slowed down in order to read the contents but no errors were reported. The LiteOn drive had the smoothest reading graph.

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 disc's surface, sized from 0.4 to 1.0 mm. It also has 65 - 75 micrometer thickness, fingerprints.

Black dots and fingerprints on the disc's surface did not create any reading problems, and all the drives finished the task successfully.