DVD Error Correction Tests

In the following tests we examined the DVD reading capabilities of the Aopen 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 screenshot from CDVD Benchmark shows that Aopen finished the DVD error correction test wihout reporting any reading errors. The yellow spots inidcate that the drive had to change speed often, especially at the begining of the defective area. The succesfull completion of the test with a final reading speed of 14x, indicates good and fast overall performance.

ABEX TDR-825

This is also a single sided, single layer DVD-ROM with 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.

Aopen proves so far to be a very good reader with defective DVD media The test finished without reading errors and the reported end speed was 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.

Most drives have difficulties during the reading process with the 841 Abex test disc but the reading performance of Aopen was unusual. CDVD Benchmark reported read errors on both layers while from 1.3Gb to 2Gb no reading mesurements are reported.

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 microns (micrometres).

The reading performance of the Aopen drive with the 845 ABex test disc on the error correction process is almost perfect. The Aopen 8x8 DVD Dual drive managed to bypass the defective areas on both layers without even needing to slow down in speed. However the above screenshot shows that the drive changed reading speed often during the switch operation for layer 0 to layer 1.

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.

Unfortunately the drive failed to read the 541 test disc. NeroCDSpeed reported unrecovered read error before the layer switch process.

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.

The error corection performance of the Aopen drive with the 545 DVD-ROM disc was very good. The drive reached 4.59x reading speed while the reported average speed was 3.44x. The disc was read smoothly under CAV without deviations to the reading velocity.