detail information

The specifications of this drive tells us that is should write DVD-R discs at 4x and DVD+R discs at 8X speed. 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 DVD-R and DVD+R discs. We used Nero burning Rom to set up a new UDF/ISO compilation containing 4482Mb of data and started the write process. We used the Disc-At-Once write method.

 
DVD+R

 
DVD-R

Out from these screenshots we could see that the Lite-On LDW-811S wrote the DVD+R in 8 minutes and 43 seconds, and the DVD-R in 15 minutes and 7 seconds. How this compares to other drives may bee seen in the table below:

For DVD+R at 8x it's 51 seconds faster than the NEC ND-2500, but 33 seconds slower than the Plextor PX-708A. But for DVD-R is rather slow and takes the last place behind all the other drives. This is due to the write speed at 4x being slightly less than 4x and that it uses longer time on finalizing the disc compared to the other writers.

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 the last two months we could 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 reports 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 LDW-411S 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/PO (Parity Inner/Parity Outer) Sum: 8 ECC, reading speed: 4X CLV (Constant Linear Velocity). Since ECC sum is set to 8 we will now call the errors PI-8 and PO-8 errors.

But what is a good scan? That is a discussion that we don't think will end soon as different drives reports 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 that only the first layer is scanned.

If you read below you will see that both the pressed DVD-discs is 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 is where K-Probe gives us problems as for PI errors it have to be set to a PI/PO sum of 8 ECC blocks to show results that compares to the standard, but for PI uncorrectable errors (Called PO in K-Probe) the PI/PO sum have to be set to a sum of 1 ECC block.

A guideline is to calculate the Parity Inner Uncorrectable errors to 8 ECC sum, which is max 32 (4 x 8) Parity Inner uncorrectable errors, but now we can't be sure if one of the 8 ECC blocks exceeds the specifications. But if the result exceeds 32 PI uncorrectable errors we know that at least one block have more than 4 PI uncorrectable 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 seems to be pretty easy affected by the quality of a written disc.

Easier explanation on how to read the test results.

Maybe this got to technical detailed and you are wondering what to look for out of the errors that K-Probe report?

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 32 PO-8 (actually PI uncorrectable) errors, do not worry too much about high single spikes that exceeds 32.

And look at the reading curve, a slight slowdown at the end is probably nothing to worry about, but huge bumps and slowdowns are not good.

And as always; lower is better ;)

DVD+R media compatibility and write quality:

The result with these Ritek 8x discs is quite good, and there should be no problems using these discs with this drive.

These discs have a bad error spike at the end, which causes the discs to be unreadable at the end. We are unsure if this is a drive or media issue as these discs have worked rather bad in most drives we have tested them in.

As we could see the amount of errors is highest at the part written at 4x, but still far from high enough to cause any problems. Highly recommended discs.

The result is quite good, and we have no problems recommending these discs.

Also discs that works very good. But you should notice that there is some quality differences from batch to batch of these discs.

Again some discs that works very good with this drive, highly recommended. The only drawback is that they are not supported at 8x speed; we have done some experimental tests and found these discs capable of 8x speed if the firmware would allow it.

These discs could also be highly recommended as there is no problems with the readability of the disc.

Notice the high spike in the beginning that may affect the readability of these discs in some players, but beside this the error level is acceptable.

The result with these BeALL manufactured discs is also acceptable and you should not have any problems with these.

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

And as we could see there are no problems and all discs are supported at their certified speed.

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