detail information

The specifications of this drive tell us that it should write DVD+R discs at 8x and DVD-R discs at 4X speed, but Philips have released it without DVD-R support. DVD-R support will be added by a firmware upgrade in September this year. In this part we will measure the write time for various types of DVD+R 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 a DVD+R disc. We used Nero burning Rom to set up a new UDF/ISO compilation containing 4483Mb of data, and started the write process. We used the Disc-At-Once write method.

DVD+R

Look below for the results.

As we could see the Philips DVDRW885 is pretty fast but still lagging some seconds behind the NU DDW-082 and the Plextor PX-708A. But speed is not everything; let us see how the writing quality is. Do the dynamic OPC really improve writing quality?

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, PO (Parity Outer) set to summarize 1 ECC block, reading speed: 4X CLV (Constant Linear Velocity). Setting the PI sum to 8 and the PO 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 is 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 8
consecutive 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 PO errors that K-Probe reports? Actually the PO errors that K-Probe reports is the Parity Inner uncorrectable errors, meaning errors left after PI correction. Only the ECMA 337 standard describes the Parity Inner uncorrectable errors. So how is a Parity Inner uncorrectable error 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 PI uncorrectable errors since every ECC block is 208 rows long. But the ECMA 337 standard goes further and specifies the max amount of accepted PI 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 PO sum is set to 1 the maximum error value should not exceed 4. The theoretical maximum value for PO errors is 208 errors.

But what makes a disc unreadable? A PO uncorrectable error will make the disc unreadable, but K-Probe does not display the PO uncorrectable errors.

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.

And 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 to 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 JLMS XJ-HD165H DVD-ROM that is using a modified firmware and thus tries to read the discs at full 16x speed. Reading the discs at full 16x speed could almost be considered a 'torture" test and most discs will slow down near the end. Only the best of the best discs will be able to get a perfect reading curve, so our limit for good discs will be: A speed drop at the end is accepted, but the reading speed should not drop below 6x for longer periods (small dips below 6x is accepted).

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.
PO(Parity Outer): No larger areas on the disc should exceed 4 PO-1 (actually PI uncorrectable) errors, do not worry too much about high single spikes that exceed 4.

And as always; lower is better ;)

And 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 is accepted).

DVD+R media compatibility and write quality:

A perfect reading curve along with a good K-Probe result shows that this media should not cause you any trouble at all.

The reading curve shows that there is some minor problems, but nothing to worry about.

Perfect K-Probe result, but the reading curve shows some problems at the end. The reading problems at the end is normal with all Mitsubishi DVD+R media when written at 8x, we guess the media quality is simply not good enough near the edge.

This Prodisc media seems to be some of the best 8x media available as all writers we have tried really likes this media! Highly recommended.

Not perfect as there is some reading problems near the end, but still very good and recommended media.

An almost perfect reading curve so we could highly recommend this media as well.

Strange - One of the worst results we obtained are with Philips own media. The PO level exceeds the standards at the end and the reading curve confirms that this media is not perfect near the end.

Right where it should be for the excellent Taiyo Yuden DVD+R media. Highly recommended media.

Very good and highly recommended. Even better than the 8x Ricoh media shown higher up on this page!

Another perfect result and you should not have any problems with this media either.

Another perfect result and we could highly recommend this media.

There is an error spike at the beginning of the disc as usual with this media. But overall there are no serious problems and you should not have any problems using this media.

To see if rather unknown media types are supported at certified speed we include the following table:

Perfect media compatibility and there are several 4x certified discs that are supported at 8x as well. And the writing quality is for the most part excellent as well.

Head on to next page and read about DVD+R DL compatibility and write quality...