DVD Error Correction Tests

In the following tests we examined the DVD reading capabilities of the LiteOn LDW-811s drive with scratched / defective DVD media. For the tests we used CDVD Benchmark and Nero CDSpeed. The reference test media come from ALMEDIO.

- Single Layer media

ABEX TDR-821

This is a single sided, single layer DVD-ROM with a 4.7GB capacity, and its surface has an artificial scratch of dimensions varying from 0.4 to 3.0 mm. The following transfer rate picture comes from the CDVD Benchmark v1.21 transfer rate test.

The drive read the 821 test disc without reporting any read errors. The yellow dots indicate that the drive gave back different reading speeds for each reading retry, due to the scratched areas. The disc was read accurately and exceeded 12x CAV.

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 the surface and instead defective areas ranging in dimensions from 0.5 to 1.1 mm. There are also fingerprints with height between 65 and 75 micrometers.

As in the previous test, no read errors occured with this disc. The drive again managed to reach maximum reading speed slightly in excess of 12x CAV.

- 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.

The first layer was read without too much fuss. However the second layer presented a few problems with the deeper scratches where the drive dropped speed before recovering and continuing on to a final maximum speed of just over 8x for both layers. The resultant output can be seen above with the speed change evident in the broken line of the second layer.

ABEX TDR-845

This disc is a single sided, dual layer DVD-ROM disc with capacity of 8.5GB. The only difference between the TDR-845 and the TDR-841 is that the first includes both defective areas and fingerprints. The dimensions of the defective areas range from 0.5 to 1.1 mm and the fingerprints have height sized from 65 to 75 micrometres.

The drive read this disc fairly effortlessly with only a few minor difficulties, primarily in the first layer. Final maxim read speed for both layers exceeded 8x.

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 on 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 sized from 0.4 to 3.0 mm.

Reading the first layer did not prove a problem, with the drive reaching a maximum of just over 8x CAV. The increase in speed is fairly constant and linear, starting at 3.58x and reaching 8.45x by the end of the first layer (outer tracks). The velocity (yellow line on the graph above) also remained fairly constant. The second layer however is quite a different tale. The drive had a lot of difficulty at the beginning (outer tracks on the disc's surface), where both transfer speed and velocity fluctuated. Only at around the 5GB mark did things settle down. Since the point of the TDV-541 test disc is to check the switch operation from layer 0 to layer 1, it is evident that the LiteOn drive had a few problems, althought it managed to surpass them.

ABEX TDV-545

The TDV-545 disc is based on the TDV-540 series. It is a single sided, dual layer Video/S-2 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 micrometre high fingerprints.

Here too, the second layer presented some difficulties although the drive did recover and continue on. Maximum speed reached was 8.40x CAV at the end of the first layer.