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Appeared on: Friday, April 28, 2006
DVD Media Quality Tests - DaTARIUS


1. Introduction

Measuring the quality of a recorded disc is a delicate and complicated procedure. Physical characteristics of a disc and the HF signals which are the output of the photo diode sensor in the play-back head, are specified by the industry in the form of standards. These standards among other things, also set down maximum and minimum levels to ensure correct operation, and it is from these limits that we can then ascertain the condition of a disc.

In order to evaluate the quality of a recorded disc, you need to examine all these parameters. Any respectable measuring procedure should be consistent, and the measuring equipment should be accurate enough to maintain measuring consistency as well as reliability. Furthermore, a measurement should be repeatable over any number of samples and should be confirmed over an adequate amount of samples.

CDRInfo presents the results of a test that started a couple of months ago. We chose some of the most popular PC burners on the market, and used them to record a number of blank discs with different Media Identification (MID) codes.

The discs were examined for recording quality with DVD Analyzers provided by DaTARIUS. The DaTARIUS DaTABANK analyzer, an industry standard, assures consistent and reliable results.

In the following pages, you will find details regarding the testing procedure, equipment, and of course, the results themselves. The results have been presented in two formats. First, we show the behavior of each disc (MID) for each of the five burners. Then, the same results are presented, but this time the behavior of each recorder for each of the discs. Although the results are essentially the same, this dual presentation is provided so as to easily gauge the performance of a particular disc with all drives, or a particular drive with all discs.


2. Test Procedure - Definitions

Disc Burning:

In an effort to ensure the integrity of the results, the disc burning setup and configuration should be the same for all discs and drives. Our PC testbed consists of a Pentium-4 workstation with the following specifications:

Intel Pentium-4 Processor 3.6 GHz/ 800Mhz FSB,
1GB DDR2-533 MHz dual channel RAM,
Seagate 120 GB 7200 rpm SATA hard drive with 8 MB cache,
Microsoft Windows XP Pro
, SP2

The recording drives (burners) used in this test include:

The PC is equipped with Nero Burning Rom 6, version v6.6.0.16 . The same image was burned onto DVD media, at the maximum allowed speed. In most cases, the speed was 16x. In cases where the burning speed was lower, this is noted in the corresponding tables.

Discs:

MID
Brand Name
Infomer30
Philips 16x DVD+R
Prodisc S05
Prodisc unbranded 16x
Prodisc F02
Prodisc unbranded 16x
Prodisc R04
Prodisc unbranded 16x
Daxon 016s
BenQ DVD-R 16x
Daxon AZ3
BenQ DVD+R 16x
CMC MAG AM3
Philips DVD-R 16x
CMC MAG M01
Ridisc DVD+R 16x
Ritek R04
Traxdata DVD+R 16x
Ritek F1
Traxdata DVD-R 16x
Optodisc R016
Optodisc DVD-R 16x
Optodisc OR16
Optodisc DVD+R 16x
RICOH JP NR03
Ricoh DVD+R 16x
MCC 004
Verbatim DVD+R 16x
MCC 03RG20
Verbatim DVD-R 16x

Definitions:

PI and PO:
Stands for Parity Inner and Parity Outer. Reed-Solomon Product Code (RS-PC) is a method of error correction employing a number of groups of Reed-Solomon parity bytes computed from rows, columns, or diagonals of a rectangular data array. DVD uses two-group method of RS-PC for error correction. The redundant codes of rows and columns are called Parity of the Inner code (PI) and of the Outer code (PO) respectively. DVD discs correct small read errors using PI, that operates on rows, and corrects large read errors using PO, that operates on columns of the data array.

PIE:
Stands for Parity Inner Error. The number of error corrections made on incoming rows of data in the first pass of the decoder using the inner parity correction code. A row of an ECC Block that has at least 1 byte in error constitutes a PI error. PIE is measured over 8 ECC blocks. In any 8 consecutive ECC Blocks the total number of PI errors before correction shall not exceed 280, as defined by the DVD specification, or ISO/IEC
16448:2002 or ecma-267, third edition, April 2001. PIE are also called as PI Sum 8.

POE:
Stands for Parity Outer Errors. Parity outer fails. The decoder was unable to correct the data using the outer parity codes. It is measured over 1 ECC block.

This test uses the measured maximum inner parity (PI Sum8) errors for recordable DVD as a high-level estimate of the quality of the media.

However, the correlation between actual loss of information and the measured maximum PIE actually depends on several factors including the playback system as well as the media
quality. The PI errors of 280 are conservative levels chosen by the recordable DVD specifications as a predictor of the onset of uncorrectable errors.

JC: Data to Clock Jitter
Jitter measurements are used to indicate the occurrence of deviations from an ideal duration. The data on an optical disc is carried by the length of the pits and the distance between them. This data is extracted with a clock signal that is synchronized with the pit edges. Jitter measurements are done by monitoring the length of the pits and the distance between them (Data to Data Jitter), and by monitoring the length between the edges of the pits and the edge of the clock (Data to Clock Jitter).

Its value is given by the standard deviation of the length of the recorded marks. It mustn't exceed 8% for DVD-R and 9% for DVD+R of the 1T reference clock signal (38.2 ns).


3. DVD Analyzer - The DaTARIUS DaTABANK
The DaTABANK quality assurance tool from DaTARIUS was used to analyze the DVD media in this test. These systems measure recorded and unrecorded DVD discs and include a Sony Reference Drive, which correlates with the Pulstec SDP-1000 optical drive, capable of measuring at speeds of up to 4x. All relevant parameters, including inner parity error (PIE), outer parity error (POF) and jitter, are measured using this system.

The DaTABANK was developed with the highest demands on measurement accuracy and flexibility of hardware and software. The system’s highly modular design, allows easy upgrades of both software and hardware.

The DaTABANK has been an industry standard media testing system, installed in the majority of optical media production plants. The system offers full control of the production process for all DVD, BD and HD DVD formats, including dual-layer recordable discs.

One of the main advantages offered by DaTARIUS for the DaTABANK system, is its easy to use user interface software, called DaTAVIEW. The software is used to operate the system, user administration, hardware monitoring, remote control and maintenance, as well as and view and manage obtained measurement results (result display & export & statistical analysis. trend charts).

DaTARIUS has developed the DaTAVIEW software, having in mind that a system should always present information in a user-friendly way.

The DaTAVIEW software is responsible for the generation of accurate charts illustrating the parameters specified for each quality measurement, filters, organizes and illustrates the data imported by the measuring system, according to the operators needs. Critical quality parameters can be isolated from the full list of measurements and be separately presented, offering easy yet stringent control over the production process. All the measurement/graph parameters, can be easily set with a few mouse clicks, in a full Windows-based environment menu interface. The operator is able to configure signals, their limits, export parameters, etc.

Below is a FE (Focus Error) sample graph for a DVD disc, as produced by the DaTAVIEW software:

A very interesting and useful tool of the DaTAVIEW software is QualityWeb. It is a dynamic viewing feature, that offers a clear and complete visual presentation of disc quality. The operator is able to configure the multiple parameters included in the display, and thus have an idea of the quality of a disc at a glance. In our example, both JC (jitter) and POF values are not graphically included within the inner area of the the red polygon and so show up as exceeding the quality limits set by the operator:

In addition, DaTAVIEW presents the disc surface diagram, which displays results from one signal (quality parameter), in a unique visual representation:

Below you can see a 3D View of an HD DVD-ROM as illustrated through the DaTABANK software (Click for larger image).

Click for larger image!

The results can be printed, saved as an archive for future reference, or exported to one of several popular formats including .csv and .xls.

DaTARIUS offers remote desktop support through the web for all the DaTABANK systems. For more information, refer to the following:

DaTARIUS Technologies GmbH
Anton Maria Schyrle-Str. 7
A-6600 Reutte
AUSTRIA
Service Hotline: +43 5672 206 206
Email: europe@datarius.com
Website: www.datarius.com

DaTARIUS Technologies Inc.
15-A Marconi Avenue
Irvine, CA 92618
USA
Service Hotline: +1 866 383 8378
Email: americas@datarius.com
Website: www.datarius.com

DaTARIUS Technologies GmbH
Unit 801-5, 8th Floor, Delta House, No. 3 On Yiu Street, Shatin,
New Territories, Hong Kong
China
Service Hotline: +852 2561 8078
Email: asia@datarius.com
Website: www.datarius.com

Testing procedure:

In our tests, we used the DaTAVIEW software to monitor JC, PI Sum8 and POF measurements. Measurements were taken at nine specific points on the disc, at a reference speed of 1x, starting from the inner tracks and progressing towards the outer, in an effort to cover the whole disc's area.

The results were exported to Microsoft Excel where the graphs were then generated. Keeping in mind that the data presented in the graphs is taken at discrete points, the graphs most likely indicate the trend of how quality changes from the inner to the outer area of a recorded disc.

The test results are presented in the ensuing pages.


4. Disc Quality Per Drive - BenQ DW-1640A

BenQ DW-1640A vBSHB

The BenQ DW-1640A performed well with the first batch of discs, as we can see in the first chart above. Note that with a DVD disc, the number of PI errors occurring in eight consecutive ECC blocks is defined as "PI-Sum8," and the maximum value for PI-Sum8 is specified as 280 or less. The average PI Sum 8 values are lower than the 280 limit and so the disc is in a good overall condition.

Things aren't the same with the next set of discs, as we can see in the following chart. More than the half of the discs showed a high PI sum 8 count, peaking as the measurements move towards the outer areas of the disc's surface. This was expected, since the DW-1640A reaches its maximum recording speed (16x using CAV) there, so the possibility of data being written close to the limits is more likely. In the following graph, the red dotted line indicates the PI Sum8 upper limit (280).

The MID codes that produced high error rates are Ritek R04, Ritek F1, MCC 03RG20, Optodisc OR16 and CMC MAG M01, as shown on the graph above. Note here, that the PI Sum8 errors are handled by the first level of error correction employed on DVDs. Their count normally represents their severity, which means that high PIE counts normally trigger Parity Output Errors which can in turn become Parity Outer Fail (POF) errors. The occurrence of POF is not acceptable for DVDs, since these are uncorrectable errors. So measuring POF for the "problem" MIDs in the previous scans is mandatory.

The results above confirm the correlation between high PI Sum 8 and the likelihood of POF. A pleasant exception is the Daxon AZ3 DVD+R disc, which returned zero POF, despite the high PI Sum 8 counts.


5. Disc Quality Per Drive - Plextor PX-716A

Plextor PX-716A v1.08

The Plextor PX-716A with firmware revision v1.08, showed decent performance, as we can see in the chart above. Something to watch out for later, is whether the high PI Sum8 counts, for the third, fourth and perhaps the seventh measurements, will lead to POF errors, although the peak value is less than the acceptable 280.

There is an issue here with the Ricoh JP NR03 DVD+R disc, with a PI Sum8 count that reaches 880. The Ritek R04 disc was also difficult to read/measure. We did not manage to get measurements for the first three points, as well as the last. The Daxon 016s DVD-R as well as the MCC 03RG20 DVD-R discs, also reported high PI Sum8 counts at different areas.

In case you are wondering, the CMC MAG M01 DVD+R and CMC MAG AM3 DVD-R discs are missing from these graphs, but with a promise to be included in the near future.

It is surprising to see POF in the case of the Ritek F1 DVD-R disc, since while the POF is located in the same area where we had previously measured high PI Sum 8, the PI Sum 8 count was well within limits (see first graph on this page).

The Ritek R04 DVD+R disc's condition could be considered as bad, since we were not able to take measurements at all points on the disc.

The Daxon 016s and the MCC 03RG20 discs also reported POFs, with the errors occurring at the same point where we had maximum PI sum 8 counts in the corresponding graph previously.


6. Disc Quality Per Drive - Pioneer DVR-110

Pioneer DVR-110 v1.22

Very low PI Sum 8 counts for the Pioneer DVR-110 v1.22 drive, shown in the graph above. However, the Prodisc S05 DVD-R as well as the R05 DVD+R discs, were burned at 4x, being limited by the drive's firmware.

The good results continue for Ritek R04 and the Optodisc R016 MIDs. The CMC MAG M01 DVD+R disc was burned at 8x speed (maximum allowed by the drive), but we see a PI sum 8 error count, close to the 280 limit, for the first measurement point:

In the following graph, we see that the MCC 03RG20 DVD-R disc produced the highest PI Sum 8 error count, far exceeding the 280 limit, while the Ritek F1 DVD-R disc hovered near the limit for the duration of the scan.

Let's take a look to the POF error counts for the last three MIDs, shown in the previous chart. MCC 03RG20 DVD-R media produced POF errors, and it was to be expected considering the high PI Sum8 levels. Interestingly enough, the Ritek F1 DVD-R disc did not generate any POF errors, despite the fact that its PISum 8 was continually near the limit.


7. Disc Quality Per Drive - LiteOn SHW-1635S

LiteOn SHW-1635S vY.S0N

On this page, we look at the LiteOn SHW-1635S vYS0N burner. The first batch of discs proved to be a good combination with the specific burner, at least judging from the PISum8 measurements shown in the graph above.

Half of the media in the graph above reported high PISum8 error rates, climbing well above the 280 limit. This increases the possibility of producing POF errors for the same media. The following graph confirms this:

Surprisingly, Ritek F1 media also produced POF errors despite having PI Sum8 values within limits. What is becoming evident however, is that there is a direct relationship between PI Sum8 and POF, and where there are peaks in the PI Sum8 graphs (especially those exceeding the 280 limit), there is a likelihood of POF errors occurring at the same point or points. Note also, that the specific graphs are essentially trends, due to the limited amount of samples (measuring positions) taken per disc.


8. Disc Quality Per Drive - NEC ND-4551A

NEC ND-4551A v1-8T

The next burner in line is the NEC ND-4551A. Good results with the first batch of discs, as we can see above.

PiSum8 errors above the limit with the Prodisc F02 DVD-R so this is one disc that could potentially produce problems (i.e. POF).

In the graph below, all media exceeded the limit. What will be interesting is to see if they all produce POF errors.

Fortunately, not all discs that exceeded the 280 limit, produced POF errors. In the chart above, we can now see the "problem" MIDs for the NEC-ND4551A, with the most prominent being Prodisc S05 DVD-R media.


9. Disc Quality Per Disc - Page 1

In the following pages we check the behavior of each disc when burned with the various burners used in this test. On top of the PI Sum8 and POF error rates, we also present the jitter charts for each disc, measured at the same area on each disc.

In general, jitter is a good indication of the condition of a recordable disc, and high values could lead to PI or even more severe errors. A jitter signal can be introduced when the spots on the recording layer of the disc (data), are not perfectly shaped. For example, they may be longer or not steep enough. High jitter compromises the integrity of the recorded data and thus, may influence the playability or lifetime, over long term. Jitter is a low-level quality measurement for optical storage media.

Note that no disc is jitter-free. The maximum allowed jitter value for the DVD+R discs is 9%, and slightly lower for DVD-R media (8%). Exceeding these values, however, does not always mean that a disc is problematic. It means that it tends to be more vulnerable to possible data corruption.

Optodisc R016 DVD-R

The first measurements with Optodisc R016 DVD-R media, show jitter above the limits, no matter the burner. The dotted red line on the graph above, indicates the 8% jitter limit for DVD-R media.

In the following graph, we can see the PI Sum8 error rates for the same MID disc, after being burned with our test drives. Highest error were rates produced by the LiteOn and the Plextor drives. The LiteOn drive also produced the highest Jitter in the graph above.

Despite having high PI values and Jitter, the discs recorded with the Plextor and LiteOn burners did not produce POF errors. POF errors were reported with the NEC ND-4551A drive which did not have a high PI Sum8 count, in fact it has very good levels there, did produce high Jitter. Perhaps what is most surprising is that the LiteOn drive, which produced high Jitter and PI Sum8, did not generate POF errors.

MCC 03RG20 DVD-R

Again, high jitter was reported for MCC 03RG20 DVD-R media burned with all the DVD burners.

The specific disc reported high PI Sum8 error counts with the Pioneer DVR-110 and the BenQ DW-1640A drives. What we then see below, is that the same drives also produced POF errors. It is also becoming evident that as the PI Sum8 count exceeds 700, it is very likely that POF errors will be produced. If the level is above 1000, then it is almost certain to do so.


10. Disc Quality Per Disc - Page 2

CMC MAG AM3 DVD-R

With CMC MAG AM3 media, we observe very good and the lowest Jitter measurements so far, with the Pioneer DVR-110, while the NEC ND-4551A produced the highest Jitter. In the following graph, we can see the PIsum8 error rates for the same drives.

The NEC ND-4551A - CMC MAG AM3 DVD-R combination produced unexpected POF errors, since we didn't see high PI errors. The behavior cannot be easily explained and the specific disc will be measured again, very soon.

Ritek F1 DVD-R

The Plextor PX-716A with Ritek F1 media created problems and it took 3 attempts before we could take a reading. Unfortunately, we could not measure the Jitter for this combination and hence the absence in the above graph.

It is difficult to find a direct connection between the jitter values measured and the PI and PO error rates. The reason for this is that the existence of both PI and PO errors is a result of many parameters. In our case, Ritek F1 DVD-R media produced POF errors when burned with the Plextor, LiteOn and the BenQ drives.


11. Disc Quality Per Disc - Page 3

Daxon 016s DVD-R

Looking at both the above graphs, we note that the Plextor PX-716A is the only drive that exceeds the limit for both Jitter and PI Sum8.

As it turns out, with Daxon 016s DVD-R media, the Plextor PX-716A and Pioneer DVR-110 drives produced POF errors.

Prodisc F02 DVD-R

Good results with the Prodisc F02 DVD-R disc. There were no POF errors, even with the NEC ND-4551A drive, which had high Jitter and PI Sum8 errors.

Prodisc S05 DVD-R

As it happens, the high jitter reported with the LiteOn and the NEC drives, corresponds to the PI errors reported with Prodisc S05 DVD-R media.

In the case of the LiteOn SHW-1635S, the POF is indicative of the high PI Sum8 reported in the graph above.


12. Disc Quality Per Disc - Page 4

Daxon AZ3 DVD+R

The Daxon AZ3 DVD+R disc produced quite good results with the drives in this test. Despite some PI Sum8 errors above the limit with the LiteOn and the BenQ drives, none of the discs produced POF errors.

Prodisc R05 DVD+R

Prodisc R05 DVD+R media also produced good results, with all the burners. Although jitter was higher than 9%, especially the Pioneer and NEC drives, the PI sum 8 error rate was very respectable, below the 280 limit, and there were no POF errors.

Ricoh JP NR03 DVD+R

High jitter values in most cases with Ricoh JP NR03 DVD+R media, with the BenQ drive being a pleasant exception.

POF errors were produced with the LiteOn drive in the outer tracks, while the Plextor and the Pioneer drives also produced some POF errors.


13. Disc Quality Per Disc - Page 5

Infomer 30 DVD+R

Strangely enough, the Informer 30 DVD+R disc did not produce any POF errors with the Pioneer drive, despite the high Jitter. The PI Sum8 values are well within specs for all drives, and as we are starting to see, Jitter probably isn't as much of a factor in generating severe errors as PI. Only the LiteOn drive produced POF errors although it was well within specs for both Jitter and PI Sum8.

Note that the discs recorded by the Plextor PX-716A could not be measured.

Prodisc R04 DVD+R

Another MID from Prodisc in this test. The Prodisc R04 DVD+R is a good choice with all the drives in our test, giving a low PI error rate and no POF errors.

Ritek R04 DVD+R

Ritek R04 DVD+R media does not seem to be the best MID for the Plextor and BenQ drives which produced POF errors. The only anomaly here is the NEC ND-4551A which had both high Jitter and PI Sum8 count above the limit, which however did not result in POF errors.


14. Disc Quality Per Disc - Page 6

CMC MAG M01 DVD+R

High jitter in all cases as illustrated above for CMC MAG M01 DVD+R media.

Possible problems with the discs burned with the LiteOn and NEC drives, with PI Sum8 error rates well above the limit.

The LiteOn SHW-1635S drive produced a very high POF error rate. The disc burned with the BenQ drive, also produced POF errors.

MCC 004 DVD+R

Again we see that any combination of drive and media which produces high PI Sum8, especially above 700, is very likely to result in POF errors. The LiteOn SHW-1635S and MCC 004 DVD+R media is just such a case. The rest of the drive/media combinations seem to be OK.

Optodisc OR16 DVD+R

The last disc in this test is Optodisc's OR16 DVD+R. The disc produced out of specs PI Sum8 with the NEC, BenQ and the LiteOn drives, while all except for the Pioneer drive, resulted in greater than 9% Jitter:

The BenQ and the LiteOn drives produced POF errors with this media. A little surprising since the PI Sum8 is not all that much above the limit although the LiteOn drive also produced a high percentage of Jitter.


15. Summary

In the matrix below you can see a summary of the results. The red color indicates that at least one measuring point showed PI Sum8 higher than 280, or POFs have occurred for each disc. The green color means that the quality results for the specific drive/disc combination is good or adequate.


16. Final Thoughts

In this article, we tried to address the critical and highly anticipated in the optical industry issue of quality of a recordable DVD disc. The test procedure was simple enough and with selected measurements for each disc, chosen so as to indicate the quality of a recorded disc, hopefully in a way understandable and familiar to our readers.

The jitter to clock measurement, was chosen in order to provide a low-level examination of a recorded disc. The PI Sum8 error measurements, indicate the integrity of the recorded data, and reveal potential problems that can manifest themselves which can make a disc harder to read or even unreadable over the course of time. POF errors, are undoubtedly the most serious errors, since they represent uncorrectable errors on the recorded media.

However, have in mind that the correlation between actual loss of information and the measured maximum PIE actually depends on several factors including the playback system as well as the media quality.

A future update of this test would require additional measurements for each disc. Measuring HF Signals such as I14/ I14H, resolution (I3/I14), I14 Modulation or Asymmetry. Servo and tracking errors such as the DPD Amplitude, DPD Asymmetry would also help determine the condition of a recorded disc.

As a last note, we should say that is is not wise to directly blame either a disc or a burner when a measurement is out of specs. Along with the various parts, the hardware makers develop the software that controls the recording procedure (recording strategy) and the media makers develop recording materials (organic/inorganic dyes, phase change, etc) and manufacturing technologies that conform to the specifications and the requirements of hardware. Of course, hardware is usually built and tweaked by using the disc as a reference, or vice versa. As a result, the combination/interaction of burners and media is the factor that decides the final quality.

In this test, we tried to give an idea of which is the most suitable burner/disc combination. Of course, not all MIDs have the same characteristics, which are dependant on the manufacturing process and the materials used. Let's skip this factor for now, and assume that the MIDs show consistent results.

In the end,, all we really want from a disc is that it should be readable, not only now but also in the long term.

CDRInfo will continue to provide detailed measurements of optical media in the future.



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