detail information

The specifications of this drive tell us that it should write DVD+R at 16x, DVD-R discs at 8x, DVD+RW and DVD-RW at 4x speed. In this part we will measure the write time for various types of DVD+R/RW and DVD-R/RW discs. We do also focus on write quality and media compatibility.

DVD-Writing performance:

In this test we will measure the time for writing to DVD+R/-R discs. We used Nero burning Rom to burn an ISO compilation containing 4483Mb of data. We used the Disc-At-Once write method.

DVD+R

DVD-R

Look below for the results.

As we can see, the AOpen DUW1608/ARR is an average drive writing DVD+R/-R, but let us see how the writing quality is.

Write quality:

You should first notice that this is not a scientific and professional way to test the discs. But according to our testing done in recent months, we would conclude that there is a clear link between the quality reported when scanning the disc and the playability of the disc in different devices. Also notice that different drives report different amounts of errors. K-Probe was designed to work with Lite-On DVD-Writers. So we recommend using a DVD-Writer from Lite-On, in this test we use a Lite-On SOHW-832S DVD-Writer, as already said; remember that scans done with a Lite-On DVD-ROM or Lite-On combo drive can't be compared with the results obtained with a Lite-On DVD-Writer. Also remember that different PI/PO ECC sum settings along with different reading speeds in K-Probe will affect the result, we use these settings;  PI (Parity Inner) set to summarize 8 ECC blocks, PIF (Parity Inner Failures) set to summarize 1 ECC block, reading speed: 4X CLV (Constant Linear Velocity). Setting the PI sum to 8 and the PIF sum to 1 will give a result that we may compare to the standards for DVD+R/RW and DVD-R/RW.

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 a scan from two pressed DVD discs:

This scan shows the results from a pressed DVD-ROM disc (Baldurs Gate DVD-ROM).

This scan shows the result from a pressed DVD-Video disk (Indiana Jones and the last crusade). Notice the error jump when shifting to the second layer (the error level actually drops from the end of the first layer to the beginning of the second layer).

If you read below you will see that both the pressed DVD-discs are well within the standards.

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 if you want to look at the standards for yourself. Here is some data from the ECMA standards (same for DVD-ROM, DVD-R/RW and DVD+R/RW):

Random errors:

A row of an ECC Block that has at least 1 byte in error constitutes a PI error. In any 8consecutive ECC Blocks the total number of PI errors before correction shall not exceed 280.

Here we see what a PI error is defined as a row in an ECC block having 1 byte or more containing errors and that the sum of PI errors in 8 ECC blocks after each other should not exceed 280 PI errors.

But what is a row and what is an ECC block? Again we refer to the ECMA standards. We do not copy and paste everything but if interested look in the ECMA standards. A row is 182 bytes long where the last 10 bytes contain PI (Parity Inner) information. An ECC block is 208 rows long where the last 16 rows contain the PO (Parity Outer) information. This gives us a maximum possible PI error amount of 208 errors per block and for 8 blocks after each other this sum is of course 8 times higher giving a maximum possible amount of 1664 PI-8 errors. In practical use a disc with 1664 PI-8 errors is unreadable.

According to our tests the specified max PI-8 sum of 280 for good discs seems to be a good guideline, as some readers have problems reading discs when the PI-8 errors is over 300 and most players starts to have problems when the PI-8 error level reaches 600 or more.

But what are the PIF errors that K-Probe reports? They are Parity Inner Failures, meaning errors left after PI correction. Only the ECMA 337 standard describes the Parity Inner Failures. So how is a Parity Inner Failure defined? Here are what ECMA 337 states:

'If a row of an ECC Block as defined in 13.3 contains more than 5 erroneous bytes, the row is said to be 'PI-uncorrectable"."

In theory an ECC block may in the worst case have 208 PIF since every ECC block is 208 rows long. But the ECMA 337 standard goes further and specifies the max amount of accepted PI Failures (uncorrectable errors) allowed on a good disc:

'- In any ECC Block the number of PI-uncorrectable rows should not exceed 4."  

This means that when the PIF sum is set to 1 the maximum error value should not exceed 4. The theoretical maximum value for PIF is 208 errors.

But what makes a disc unreadable? A POF (Parity Outer Failure) error will make the disc unreadable, but K-Probe does not display the POF's.

Notice that there are other aspects such as disc reflectivity, jitter, 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 CLV 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.

Easier explanation on how to read the test results.

Maybe this got too technical, and you are wondering what to look for in Kprobe reports?

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; lower is better

Look at the reading curve, some slowdowns is expected with most media, but the reading speed should not drop below 6x for longer periods (small dips below 6x are accepted).

DVD+R media compatibility and write quality:

Very high PI and PIF errors, and as expected the disc was not readable at the end of the disc.

This 16x certified media was burned at 12x! The Kprobe result is ok and the reading curve shows a speed drop in the beginning and at the end of the disc.

The result is perfect!

This 8x certified media was burned at 4x. The Kprobe result shows a lot of PIF spikes. The DVD was not readable.

This 8x media was burned at 4x. The Kprobe result got high PI and PIF and as expected, the DVD was not readable.

Some high PIF spikes at the end of the disc - according to Kprobe. The reading curve showed us a speed drop at the end of the disc.

Some high PI spikes in the beginning of the disc, but the reading curve is good. (The DVD-ROM would only read this disc at max 12x).

DVD+ReWritable media:

There are a lot of high spikes in the KProbe result, but the reading curve is close to perfect.

Amazing, good KProbe result and the reading curve is perfect.

The KProbe result shows a lot of PIF errors, but it did not affect the reading curve - which is perfect.

Excellent KProbe result (except from the high PI spikes at the beginning of the disc). The reading curve is perfect.

The DVD+R media quality is overall not good at all, and would need some improvements. The drive tend to be very picky on which media it can write with good quality! We only managed to write ONE DVD+R 16x certified media at 16x, due to some media that are downgraded in the writing speed.

On the next page you will find the DVD-R/RW writing results...