Frequently Asked Questions

1. Why some selections in the View Tests page are grayed out?

Depending on the grayed out option, this might happen due to several reasons.

For the case "Enhanced Recording Mode" (RecModeEnhanced), we decided, for the time being, not to offer this option publicly, in order to keep the user selections as simple as possible. We might reconsider this in the future if there is a many members’ request for doing so. The same applies in the case of "Enhanced Audio Recording Mode" (RecModeAudioEnhanced).

In the case of the reading Program, we have restricted the available options (presently) to only 2: KProbe and UmDoctor, because currently these are the only programs offering text output in the form of the so-called csv file. Otherwise, each user should have to use a graphics to vector translation application (like the one included with CorelDraw, for example) for doing it. We think there is no much sense into pursuing such an endeavor and hence we have presently disabled the inclusion of tests produced by PlexTools and CdSpeed.

2. I have fixed some selections on some list-boxes and there is no way now for me to add additional tests. Can you please fix the page?

This not a problem of the page. You have just imposed restrictions on the degrees of freedom of the system that lead to tests that do not exist in our database. So, this is a problem related not to the page design itself, but rather to the use of it made by our users.

Please unfix some of the list-boxes (just try one-by-one) until you are led to cases were there are available tests in our database, among which you can make more selections.

3. I choose one particular test for viewing. It shows OK. Then, keeping the same test selection parameters, I choose the [Average] of the available tests. Instead of seeing 2 tests, I see only 1. What's the problem? The same holds when I choose [Best] or [Worst].

You have chosen parameters which lead to only 1 available test. In this case the Average is the same as the test itself. The same holds for the Best and Worst cases. So this is normal, as each curve overlaps another one. In order to be able to get distinguishable curves you will have to choose parameters which lead to more than 1 available tests!

4. I have measured the same disc with the same reader/software, but the results are different. In the first case I chose the 4x reading speed, while in the second one I chose the maximum allowed by the reader. What is the problem?

Considering the fact that the reported results are closely related to the reading quality of your drive, we could say that such results were expected. Higher reading speeds could affect the results, not always negatively, however. For this reason, we have chosen to include the reading speed selection in our test suite, in order the user to be able to identify the speed at which each disc was read at. It is up to you whether you want to compare discs tested at the same speed to keep a reference, or not.

5. Latest versions of KProbe have an "ECC" setting at the left of the main PI/PO window. Which ECC setting should I select from the available 1-10 scale?

There is not any clear answer to this, since the KProbe measuring mechanism is not clearly defined until now. Again, keeping a stable setting for your measurements could make things easier in order to have a reference when comparing the test results. In most cases, CdrInfo.com sets the ECC setting to 8.

It might be the case that this value defines the mesh of the graph, which essentially refers to how distant one measurement lays from the previous and the next ones. In this case choosing a particular scale number is irrelevant. This is due to the fact that before submitting your test results, these are necessarily summed-up per 2 minutes for database storage efficiency.

6. What is the acceptable levels of PI/PO and C1/C2 error rates?

1. Parity Inner and Parity Outer Errors for DVD (ECC=8):

• DVD PI<280/sec (standard)
• DVD PI<<280/sec (good quality)
• DVD PO = 0

2. C1 and C2 errors for CD:

C1=E11+E21+E31

C2=E12, E22 and E32

• E22- Approaching uncorrectable error
• E32- Uncorrectable
• CD E22 and E32 = 0

BLER (Block Error Rate – CD only) = E11 + E21 + E31 per second averaged over ten seconds.

One or more bad bits in any frame

• CD BLER< 220/sec (standard)
• CD BLER<< 220/sec (Good quality)

6. KProbe offers 3 different options regarding the address on the CD and DVD. The MSF, LBA and Disc size. What should I choose for measuring my discs?

In general, the "Disc Size" option will work with your CD and DVD media. You should choose this option in order the software to automatically measure the whole disc inserted to your reader. (Please also choose to fill the disc with data completely during recording.)

Generally for a CD:

M:S:F (Minutes:Seconds:Frames) is the original unit used for addressing the positions of a CD. A frame is actually a sector and the unit corresponds to 75 frames in 1 second.

LBA (Logical Block Addressing) is also known as sector of a CD. In the MMC specification document where it is described, there is a defined range for the mapping of MSF to LBA values.

Sectors of the CD are defined as signed long integer values to account for negative values. Here's the relationship:

Positive values are mapped:

MMC LBA:0~403964 to MSF: 00:02:00~89:59:74

and negative values are mapped accordingly:

Below 2 secs (MSF), ranging from 00:00:00 to 00:01:74 (MSF) are represented as MMCLBA: -150 to -1.

The range from 90:00:00 to 99:59:74 (MSF) are represented as MMC LBA: -45150 to -151.

The range of MMC LBA is a linear range with the integer values starting from -45150 to 403964. However, it is not linear comparing with Red Book Addressing (MSF) because it wraps around.

Logical Block Addressing are the mapped integer numbers from CD Red Book Addressing to MSF. It is also known as sectors of a CD. Other people may have different interpretations for LBA, or simpler:

The starting sector is -150 and ending sector is 449849, which correlates directly to MSF: 00:00:00 to 99:59:74. This removes the wrapping as in MMCLBA representation and the transformation will be linear when comparing with the Red Book Addressing (MSF).