Page 5 DVD+R/RW writing performance

The specifications of this drive tell us that it should write DVD±R at 8X, DVD+RW at 8x, and DVD-RW at 6x. In this next section we will measure the write time for various types of DVD+R/RW and DVD-R/RW discs. We will also focus on write quality and media compatibility.

DVD+R/RW writing performance:

Let us see how long it takes the LG GGC-H20L to create an 16X disc. We used Nero Burning Rom to set up a new UDF/ISO compilation containing 4480MB (4.36GB) of data, and started the write process. We used the Disc-At-Once write method.

DVD+R

DVD-R

Now let us see how the writing quality is.

Write quality:

Disc Quality Scanning - PI/PO:

DVDs use an error detection and correction system (ECC) which is usually transparent to the end-user, but we can get an idea of the "quality" of a disc by  performing Disc Quality Scanning, which shows how many errors the drive is detecting and correcting behind the scenes.

There are two layers or stages of error detection and correction on all DVD media; these are called Parity Inner (PI) and Parity Outer (PO). Data is arranged in ECC blocks containing rows and columns of user data with additional columns of PI error correction and rows of PO error correction.

An ECC block contains 32 kByte of user data with some added control data, scrambled and arranged in 192 rows and 172 columns with an additional 10 columns of PI error correction and 16 rows of PO error correction.

The Parity Inner stage is performed first, and up to 5 bytes in a row can be corrected. Any row with one or more errors is counted as a Parity Inner Error (PIE). Any row with more than 5 errors is considered uncorrectable and is counted as a Parity Inner Failure (PIF).

The Parity Outer stage is performed next and will detect and attempt to correct any errors that are still left after the PI stage. Any column that has errors is counted as a Parity Outer Error (POE), and any column that has uncorrectable errors is counted as a Parity Outer Failure (POF). If a POF occurs the drive can sometimes re-read the problematic spot and correct the problem; this happens only during normal reading and not during scanning, however.

Disc Quality scanning is influenced by the drive performing the test, and that's why different drives report different results and even the same drive will report (slightly) different results when scanning the same disc again. Please note that PI/PO and Jitter scans only test some aspects of disc quality and that other important aspects are not revealed.

But what is a good scan? That is a discussion that we don’t think will end soon, as different drives report different amount of errors, some players are more picky about media than others, and so on. But as a comparison we present you with scans from two pressed DVD discs:

This scan above shows the results from a pressed, Single Layer DVD-Video disc (Flicka).

This above scan shows the result from a pressed Double Layer DVD-Video disc (MI3).

The Lite-On DVD burners used in this review report errors as follows.

• PIE per 8 ECC blocks (rows with 1 or more bytes in error)

• PIF per 1 ECC block (rows with 6 or more bytes in error)

We want to see as low error numbers as possible.
PIE per 8 ECC blocks should be no higher than 280.
PIF per 1 ECC block should be no higher than 4.

Both the pressed DVD-discs above are well within the standards.

If you want to look at the standards for yourself, download the ECMA 267 Standard for DVD-ROM, the ECMA 337 Standard for DVD+R/RW and the ECMA 338 Standard for DVD-R/RW at http://www.ecma-international.org.

Notice that there are other aspects such as disc reflectivity, tracking errors and so on that also will affect the readability of a DVD disc – but for this we do not have measuring equipment available.

Also, another note is that we have scanned the discs at 4X speed, by lowering the speed to 2X (DVD-R/RW)/2.4X (DVD+R/RW) or 1X the amount of reported errors may drop on some discs. We scanned at 4X CLV due to lower speeds taking too much time.

To see if there is a connection between the reported amount of errors and readability of the discs we also include the reading curve from a BenQ DW1655 DVD-Writer which by default is able to read DVD±R media at 16x speed. A small speed reduction near the end is still accepted on good discs, but serious reading problems or reading failures is a bad sign.

Here is an easier explanation on how to read the test results

Maybe this got too technical, and you are wondering what to look for in your Nero DiscSpeed Quality Scans?

Use this as a guideline for good discs:

• PI (Parity Inner): No larger areas on the disc should exceed 280 PI-8 errors, do not worry too much about high single spikes that exceed 280.

• PIF (Parity Inner Failures): No larger areas on the disc should exceed 4 PIF-1 errors, do not worry too much about high single spikes that exceed 4.

And as always: the lower is better.

DVD+R media compatibility and write quality 

In these tests we will be using a Lite-On DH20A3P drive along with Nero CD-DVD Speed to measure the disc quality. We will provide you with an image of the Quality Scan, Transfer Rate Test (TRT), and a Table which gives the pertinent details for the burn and quality scan to include the number of samples taken in the Quality Scan. We will also be using the BenQ DW1655 along with Nero CD-DVD Speed for our read-back tests.

Disc quality is Excellent and the Transfer Rate Test has a smooth curve.

The media burns with Good results and the Transfer Rate Test has a smooth curve.

The media burns with Good results and the Transfer Rate Test has a smooth curve.

The media burns with excellent results and the Transfer Rate Test has a smooth curve.

Editors Note: The fastest possible burn speed for this media is 12x.

The media burns with excellent results and the Transfer Rate Test has a smooth curve.

The media burns with excellent results and the Transfer Rate Test has a smooth curve.

The media burns with excellent results and the Transfer Rate Test has a smooth curve.

The media burned with excellent results and the Transfer Rate test has a smooth curve.

DVD+ReWritable media:

The LG GGC-H20L supports writing to DVD+RW discs at maximum 8X speed.

The media burns with good results except for a high PI-8 error at the beginning of the disc but the Transfer Rate Test has a smooth curve.

On the next page let’s take a look at the DVD-R/RW Writing Performance...

CD-R/RW discs Writing Performance

DVD-R/RW Writing Performance