1. About the Blu-ray Disc Quality Measurements
Within a couple of years, the Blu-ray burners have become faster and have possibly reached their limits today by offering recording at Blu-ray recordable discs at 8x (although the 12x could be also achievable in theory).
Looking back some years ago when the development of the DVD recordable format was in full progress, we can easily say that the burning speeds for the DVD+R/-R as well as the DVD+RW/-RW were gradually increased, taking quite a long period to reach today's 24x limit.
It is obvious that the Blu-ray disc and drive makers have been eager to push the writing speeds of their products in an effort to make the Blu-ray disc format more attractive to PC users, offering quick burnings of huge amounts of data stored in BD-R SL and DL discs.
The latest Blu-ray disc burners are currently offering recording speeds of up to 8x for the Blu-ray recordable discs. The question here is whether these high-speed burnings are reliable and these 8x BD-Rs will be readable over a very long period of time.
In general, the readability of a disc depends on the reading drive, which is influenced by the
resultant writing quality produced on the disc, which is in turn
directly related to the recorder used for burning
and the optical medium itself.
Today we test the quality of some of the BD-R SL and DL media after being recorded with the Pioneer BD-R 203BK and Sony BWU-300S 8x BD burners.
Although measuring the quality of a disc is complicated and requires reliable testing equipment, we needed to have a first idea of what a user should expect from a high-speed BD-R burning.
For our tests, we used the Opti Drive Control software by Erik Deppe together with a LiteOn DH-4O1S BD-ROM drive as a reader. The software offers a quality disc scanning option and reports two signals that give indications (signals) of the digital errors found during the reproduction of a Blu-ray disc. These signals provide information about
the physical condition of a disc and the integrity
of the digital data, as they are stored on the disc
and retrieved by the player. You can find more information about the test configuration and methodology in the following pages.
We are not sure that out tests will make a clear statement on the playability of the Blu-Ray media and their reliability. The Blu-ray format is squeezing huge amount of data onto 12cm
media using various techniques, so it's easy to
understand why measuring the quality of the
recorded data is more complicated when compared to CD and
DVD.
The Blu-ray disc format is uses a laser with a Numerical Aperture of 0.85nm. This means that the laser beam that accesses the data is very narrow, compared to CD and DVD. As a result, the laser beam can be easily diffracted by small particles or defects that exist on the disc's surface. The size of these particles could be microscopic, as in the case of the dust or smoke. So measuring the quality of a Blu-ray disc requires extremely careful cleaning of the disc surface first.
In addition, the equipment we used for this test is actually a home brew PC system and the reader we used, no matter how good, will time degrade in performance, not to mention the fact that with different drives (readers) it is most probable that we will get different results as it happened in case of DVD testing. If the drive's (reader) characteristics are not constant, then it will not be possible to have a reproducible test system to accommodate and correctly measure Blu-ray burning quality.
Technically speaking, it really isn't wise to expect very reliable results here using a common off the market drive and PC application such as the Opti Drive Control software and a commercial BD reader, at least compared to those produced by a professional test system. However, we hope that we will have a rough idea of the condition of the data stored on a BD-R disc burned at high speeds.
2. Testing process
For this test we used the Pioneer BDR-203BK and a Sony BWU-300S BD burners. A combination of Blu-Ray burners and BD-R/RE media were used for this test. All discs were burned at the highest allowed speed using the "Create Disc" function of Nero's CDSpeed utility, which burns the disc with data to its full capacity.
In the table below, you can see all the available media and burners we used in this test.
Media brand |
Media ID |
Media type / Certified speed |
Nominal capacity |
Burner |
Write speed |
Panasonic |
MEIRB1 (001) |
BD-R 6X |
50 GB |
Pioneer BDR-203BK v1.10 |
8X |
Verbatim |
VERBATIMb (000) |
BD-R 2X |
50 GB |
2X |
TDK |
TDKBLDRFD (000) |
BD-R 6X |
50GB |
8X |
Moser Baer India |
MBIR06 (000) |
BD-R 6X |
25 GB |
8X |
Panasonic |
MEIRA1 (001) |
BD-R 6X |
25 GB |
8X |
TDK |
TDKBLDRBB (000) |
BD-R 4X |
25 GB |
8X |
TDK |
TDKBLDRBD |
BD-R 6X |
25GB |
8X |
Verbatim |
VERBATIMc (000) |
BD-R 4X |
25GB |
8X |
Verbatim |
VERBATIMe (000) |
BD-R 6X |
25GB |
8X |
Verbatim |
VERBATIMw (000) |
BD-R LTH 2X |
25GB |
2X |
Verbatim |
VERBATIM0 (000) |
BD-RE 2X |
7.5GB |
2x |
Verbatim |
VERBATIM0 (000) |
BD-RE 2X |
25GB |
2X |
TDK |
TDKBLDWfa (000) |
BD-RE 2X |
50GB |
2X |
Verbatim |
VERBATIMa (000) |
BD-R 2x |
7.5GB |
2X |
Panasonic |
MEIRB1 (001) |
BD-R 6X |
50GB |
|
8X |
Verbatim |
VERBATIMb (000) |
BD-R 2X |
50GB |
2X |
Moser Baer India |
MBIR06 (000) |
BD-R 6X |
25GB |
6X |
Panasonic |
MEIRA1 (001) |
BD-R 6X |
25GB |
8X |
Verbatim |
VERBATIMe (000) |
BD-R 6X |
25GB |
6X |
Verbatim |
VERBATIMc (000) |
BD-R 4X |
25GB |
4X |
Verbatim |
VERBATIMw (000) |
BD-R LTH 2X |
25GB |
2X |
Verbatim |
VERBATIM0 (000) |
BD-RE 2X |
25GB |
2X |
Verbatim |
VERBATIM0 (000) |
BD-RE 2X |
7.5GB |
2X |
As we previously mentioned, the software we used was the Opti Drive Control v1.21 by Erik Deppe and the reader was a LiteOn DH-4O1S vCP56 BD-ROM drive. The measuring speed was set at 4X.
Before testing, each disc was cleaned using air spray and special tissues. After cleaning, no dust particles or any visible signs of handling, such as minor scratches and fingerprints were identified in naked eye.
The OptiDrive Control v1.21 software has a "Disc Quality" function for Blu-ray discs. This function will scan the disc and report error parameters. For BDs the following parameters are measured:
- LDC (Long Distance Code): number of parity errors on LDC codewords per ECC block (32
sectors)
- BIS (Burst Indication Subcode): number of parity errors on BIS codewords per ECC block
(32 sectors)
On a good disc the average LDC should stay below 13 and BIS should stay below 15, according to the author of the software.
Notice here that we have to do with the average values of these signals and not the maximum, which are present on the quality graphs as peaks. The software also reports jitter values.
Let's say a few words about the LDC and BIS signals.
For Blu-ray disc, , the Partial Response- Maximum likelihood (PRML) method is used for recovering the data from the signal.
Partial Response (PR) equalization is used to limit the effects of ISI, and then a sequence of bits is evaluated to define the most likely sequence of bits, based upon known allowed sequences. This is the Maximum Likelihood (ML) detection and uses a Viterbi algorithm to determine the ML sequence.
The Blu-Ray disc is more sensitive to burst errors compared to the DVD system. Therefore, the error correction system of Blu-Ray disc should be able to cope well with long burst errors, rather with single (random) errors.
The maximum number of errors that can be corrected depends on the number of parity symbols added. For each two parity symbols added, one error can be corrected. But Blu-Ray uses a more efficient approach to correct the burst errors. It uses a burst indicator mechanism that can detect bursts of errors before the correction starts. The advantage of this method is actually the prior knowledge of the error locations on the decoding process.
These burst indicator used in the Blu-Ray format is called picket code. The pickets are columns that are inserted in between columns of the main data at regular intervals. The main data is protected by a Reed Solomon code, while the pickets are protected by a second independent Reed Solomon code. When decoding (reading), first the picket columns are corrected. The correction information can be used to estimate the location of possible burst errors in the main data.
A BluRay Disc Error Correction Block (ECC Block) can store 64 Kilobytes of user data. This data is protected by the Long Distance Code (LDC) which has 304 code words with 216 information symbols and 32 parity symbols giving a code word of length 248.
A Blu-Ray Disc ECC block contains 4 equally spaced picket columns. The left most picket is formed by the sync pattern at the start of each row. If the sync pattern was not detected properly, that can be an indication for a burst error similar to the knowledge that a symbol of a picket column had to be corrected. The other three pickets are protected by the so-called Burst Indicator Subcode (BIS). The BIS code words are interleaved into three columns of 496 bytes each. Both LDC and BIS codes are decoded by the Reed Solomon decoder.
For additional information about the Blu-ray's error correction, modulation and quality signals read our previous Blu-ray Writing Quality article.
In the following pages we present the measurements for each disc.
3. Pioneer BDR-203BK Disc quality measurements - Panasonic BD-R DL 50GB 6x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Panasonic BD-R DL 50GB 6x |
Media ID |
MEIRB1 (001) |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
The average LDC value was very high here at 105.90. Average BIS remained well within the acceptable limits. Jitter was also high especially in the L1 of the disc (yellow, red spikes).
4. Pioneer BDR-203BK Disc quality measurements - TDK BD-R DL 50GB 6x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
TDK BD-R DL 50GB 6x |
Media ID |
TDKBLDRFD (000) |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/Write.png)
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
This time the average LDC and BIS values were higher in the L0 and it seems that the errors were more severe in the beginning and the end of the data area. However, the disc was fully readable.
5. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-R DL 50GB 2x burned at 2x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-R DL 50GB 2x |
Media ID |
VERBATIMb (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.png)
- Digital errors
 2x/Disc_quality.jpg)
The disc's condition seems to be better this time with both LDC and BIS to remain relatively low. Higher errors were reported around the area where the drive accessed the end of L0 and the beginning of L1.
6. Pioneer BDR-203BK Disc quality measurements - Moser Baer India BD-R SL 25GB 6x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Moser Baer India BD-R SL 25GB 6x |
Media ID |
MEIRB1 (001) |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
It is obvious that the end of the data area is the problem here with the LCD, BIS and especially jitter to rise sharply.
7. Pioneer BDR-203BK Disc quality measurements - Panasonic BD-R SL 25GB 6x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Panasonic BD-R SL 25GB 6x |
Media ID |
MEIRA1 (001 |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
The Pioneer drive successfully burned this 4x BD-R at 8x Z-CLV.
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
Many errors were reported again after the 15GB mark.
8. Pioneer BDR-203BK Disc quality measurements - TDK BD-R SL 25GB 4x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
TDK BD-R SL 25GB 6x |
Media ID |
TDKBLDRBB (000) 4x |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
-Read
 8x/read.png)
Digital errors
 8x/Disc_quality.jpg)
The specific TDK BD-R is certified fro 4x burning and it was a pleasant surprise for us after seeing all the previous results with BD-Rs burned at 8x. Despite the high errors reported in the beginning of the data area, the average LDC and BIS flags was close to the acceptable limits.
9. Pioneer BDR-203BK Disc quality measurements - TDK BD-R SL 25GB 6x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
TDK BD-R SL 25GB 6x |
Media ID |
TDKBLDRBD |
Writing speed |
8x Z-CLV |
- Write
-Read
- Digital errors
The graphs are disappointing here with all the signals to be very high. However, the disc was readable although the CDSpeed transfer rate graph was not very smooth after the 12.5GB mark.
10. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-R SL 25GB 4x burned at 8x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-R SL 25GB 4x |
Media ID |
VERBATIMc (000) |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
Again the 4x BD-R disc was recorded at 8x.
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
The relatively high LDC value does not allow us to consider the result as a successful one, although we have seen much worse results previously. The disc was fully readable.
11. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-R SL 25GB 6x burned at 8x
Blu-ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-R SL 25GB 6x |
Media ID |
VERBATIMe (000) |
Writing speed |
8x Z-CLV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
The spike in the above graphs is most probably caused by a local defect on the disc which we missed when we cleaned its surface prior to the test. But this spike was not the main problem here since the average LDC was extremely high at 251.57.
12. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-R SL 25GB LTH 2x burned at 2x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-R SL 25GB LTH 2x |
Media ID |
VERBATIMw (000) |
Writing speed |
2x CLV |
 LTH 2x/Disc_info.jpg)
- Write
 LTH 2x/write.png)
-Read
 LTH 2x/read.png)
- Digital errors
 LTH 2x/Disc_quality.jpg)
A generally good result with the new Verbatim BD-R LTH disc at 2x, despite the high spikes on the graph in the end of the data area. Both the average LDC and BIS were off limits but still close to the acceptable levels.
13. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-R DL 7.5GB 2x burned at 2x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-R DL 7.5GB 2x |
Media ID |
VERBATIMa (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.png)
- Digital errors
 2x/Disc_quality.jpg)
This is the first result that actually meets the acceptable limits.
14. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-RE SL 7.5GB 2x burned at 2x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-RE SL 7.5GB 2x |
Media ID |
VERBATIM0 (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.png)
- Digital errors
 2x/Disc_quality.jpg)
The problems reported in the beginning of the disc raised the average LDC value here.
15. Pioneer BDR-203BK Disc quality measurements - Verbatim BD-RE SL 25GB 2x burned at 2x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
Verbatim BD-RE SL 25GB 2x |
Media ID |
VERBATIM0 (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.png)
- Digital errors
 2x/Disc_quality.jpg)
Both the average LDC and BIS values were relatively low for the specific disc. We should note here that the isolated spikes on the graph should be attributed to local defects on the disc surface in most cases.
16. Pioneer BDR-203BK Disc quality measurements - TDK BD-RE DL 50GB 2x burned at 2x
Blu-Ray burner |
Pioneer BDR-203BK v1.10 |
Disc |
TDK BD-RE DL 50GB 2x |
Media ID |
TDKBLDWfa (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.png)
- Digital errors
 2x/Disc_quality.jpg)
The extremely high LDC spikes had a negative effect on the average LCD result. The result cannot be considered as a successful one although the disc was readable.
17. Sony BWU-330S Disc quality measurements - Panasonic BD-R DL 50GB 6x burned at 8x
Blu-Ray burner |
Sony BWU-330S v1.06 |
Disc |
Panasonic BD-R DL 50GB 6x |
Media ID |
MEIRB1 (001) |
Writing speed |
8x P-CAV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
-Read
 8x/read.gif)
- Digital errors
 8x/Disc_quality.jpg)
18. Sony BWU-330S Disc quality measurements - Verbatim BD-R DL 50GB 2x burned at 2x
Blu-Ray burner |
Sony BWU-330S v1.06 |
Disc |
Verbatim BD-R DL 50GB 2x |
Media ID |
VERBATIMb (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.gif)
Digital errors
 2x/Disc_quality.jpg)
The average LDC is high but not as high as in the previous cases.
19. Sony BWU-330S Disc quality measurements - Panasonic BD-R SL 25GB 6x burned at 8x
Blu-Ray burner |
Sony BWU-330S v1.06 |
Disc |
Panasonic BD-R SL 25GB 6x |
Media ID |
MEIRA1 (001) |
Writing speed |
8x P-CAV |
 8x/Disc_info.jpg)
- Write
 8x/write.png)
-Read
 8x/read.png)
- Digital errors
 8x/Disc_quality.jpg)
High errors were reported around the 15GB mark. The average BIS is low at 1.74 and the LDC is increased again.
20. Sony BWU-330S Disc quality measurements - Moser Baer India BD-R SL 25GB 6x burned at 6x
Blu-Ray burner |
Sony BWU-300S v1.06 |
Disc |
Moser Baer India BD-R SL 25GB 6x |
Media ID |
MBIR06 (000) |
Writing speed |
6x Z-CLV |
/Disc_info.jpg)
- Write
/write.png)
-Read
- Digital errors
/Disc_quality.jpg)
An acceptable result with the Moser Baer BD-R at 6x.
21. Sony BWU-330S Disc quality measurements - Verbatim BD-R SL 25GB 6x burned at 6x
Blu-Ray burner |
Sony BWU-300S v1.06 |
Disc |
Verbatim BD-R SL 25GB 6x |
Media ID |
VERBATIMe (000) |
Writing speed |
6x Z-CLV |
- Write
-Read
- Digital errors
This time the Verbatim BD-R disc did not worked very well with the Sony drive at 6x with the average LCD to reach the 251.57 and the jitter to increase after the 15GB mark.
22. Sony BWU-330S Disc quality measurements - Verbatim BD-R SL 25GB 4x burned at 4x
Blu-Ray burner |
Sony BWU-300S v1.06 |
Disc |
Verbatim BD-R SL 25GB 4x |
Media ID |
VERBATIMc (000) |
Writing speed |
4x CLV |
 4x/Disc_info.jpg)
- Write
 4x/write.png)
-Read
 4x/read.gif)
- Digital errors
 4x/Disc_quality.jpg)
The 4x CLV writing strategy seems to be the right choice with the specific disc. The error flags were increased but not as much as we experienced with other discs.
23. Sony BWU-330S Disc quality measurements - Verbatim BD-R SL 25GB LTH 2x burned at 2x
Blu-Ray burner |
Sony BWU-300S v1.06 |
Disc |
Verbatim BD-R SL 25GB LTH 2x |
Media ID |
VERBATIMw (000) |
Writing speed |
2x CLV |
- Write
-Read
- Digital errors
A disappointing result at 2x with the Verbatim 2x BD-R LTH disc.
24. Sony BWU-330S Disc quality measurements - Verbatim BD-RE SL 7.5GB 2x burned at 2x
Blu-Ray burner |
Sony BWU-300S v1.06 |
Disc |
Verbatim BD-RE SL 7.5GB 2x |
Media ID |
VERBATIM0 (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.gif)
- Digital errors
 2x/Disc_quality.jpg)
25. Sony BWU-330S Disc quality measurements - Verbatim BD-R SL 25GB 2x burned at 2x
Blu-Ray burner |
Sony BWU-300S v1.06 |
Disc |
Verbatim BD-R SL 25GB 2x |
Media ID |
VERBATIM0 (000) |
Writing speed |
2x CLV |
 2x/Disc_info.jpg)
- Write
 2x/write.png)
-Read
 2x/read.gif)
- Digital errors
Not so bad here with the average LCD to be 58.05 and the BIS at 1.10.
26. Final thoughts
The results were disappointing for almost all the discs. As you can see in the table below, both the LDC and BIS signals were well above the acceptable limits. Only the Verbatim BD-R 2x 7.5GB disc reported good results with the Pioneer BD burner, followed by the TDK BD-R 4X 25GB burned at 8x with the same drive and the Moser Baer India BD-R 6X 25GB burned at 6x with the Sony drive:
BD Disc |
Write speed |
Burner |
Average LDC (upper limit 13) |
Average BIS (upper limit 15) |
Panasonic BD-R 6X 50GB MEIRB1 (001) |
8X |
Pioneer BDR-203BK v1.10 |
105.90 |
1.58 |
Verbatim BD-R 2X 50GB VERBATIMb (000)
|
2X |
58.19 |
0.79 |
TDK BD-R 6X 50GB TDKBLDRFD (000) |
8X |
105.3 |
43 |
Moser Baer India BD-R 6X 25GB MBIR06 (000) |
8X |
94.61 |
1.94 |
Panasonic BD-R 6X 25GB MEIRA1 (001) |
8X |
121.22 |
2.47 |
TDK BD-R 4X 25GB TDKBLDRBB (000) |
8X |
27.12 |
0.36 |
TDK BD-R 6X 25GB TDKBLDRBD |
8X |
660.94 |
14.26 |
Verbatim BD-R 4X 25GB VERBATIMc (000) |
8X |
41.55 |
0.64 |
Verbatim BD-R 6X 25GB VERBATIMe (000) |
8X |
251.57 |
6.19 |
Verbatim BD-R LTH 2X 25GB VERBATIMw (000) |
2X |
70.33 |
1.19 |
Verbatim BD-RE 2X 7.5GB VERBATIM0 (000) |
2x |
73.12 |
1.38 |
Verbatim BD-RE 2X 25GB VERBATIM0 (000) |
2X |
58.04 |
1.10 |
TDK BD-RE 2X 50GB TDKBLDWfa (000) |
2X |
162.35 |
3.36 |
Verbatim BD-R 2x 7.5GB VERBATIMa (000) |
2X |
11.64 |
0.23 |
Panasonic BD-R 6X 50GB MEIRB1 (001) |
8X |
|
72.05 |
1.67 |
Verbatim BD-R 2X 50GB VERBATIMb (000) |
2X |
55.36 |
0.91 |
Moser Baer India BD-R 6X 25GB MBIR06 (000) |
6X |
24.78 |
0.58 |
Panasonic BD-R 6X 25GB MEIRA1 (001) |
8X |
79.79 |
1.74 |
Verbatim BD-R 6X 25GB VERBATIMe (000) |
6X |
251.57 |
6.19 |
Verbatim BD-R 4X 25GB VERBATIMc (000) |
4X |
67.90 |
1.30 |
Verbatim BD-R LTH 2X 25GB VERBATIMw (000) |
2X |
388.67 |
4.81 |
Verbatim BD-RE 2X 25GB VERBATIM0 (000) |
2X |
58.04 |
1.10 |
Verbatim BD-RE 2X 7.5GB VERBATIM0 (000) |
2X |
207.31 |
4.11 |
When you are dealing with complicated measurements such as those required for checking the quality of the Blu-ray discs, it would be wise to avoid any bold statements and conclusions. That because our tests were performed using equipment that was actually a home brew PC system and the BD-ROM reader/software, which are always lack accuracy and repeatability. In addition, consider that you cannot ensure that the surface of each disc is completely free of any microscopic particles microscopic such as dust or smoke when you make a measurement.
For all the discs, the Long Distance Code (LDC) values were higher than the Burst Indicator Subcode (BIS), which is normal since the first is related to the error correction code added in each data sector to protect the main data and the latter is actually protecting the pickets, which are columns that are inserted in between columns of the main data at regular intervals and works as a burst indicator mechanism that can detect bursts of errors.
So what could have caused these 'bad' results?
- Not reliable software/reader
- Insufficiently cleaned discs
- Poor writing strategy of the BD burners for each speed, especially for the 6x and 8x
- Low media quality
It 's really hard to come up with any conclusions just from a single test. But it would be safe to say that disc we used for the test were brand new and their quality must be adequate if not high. In addition, all the discs were carefully cleaned and looked in perfect shape with naked eye before testing. But is the 8x burning speed very high for the disc found on the stores today? Soon we will be able to test the same discs using more reliable equipment.
On the other hand, testing the discs 'out of the box' after cleaning them is closer to the scenario of a consumer using a Blu-ray recordable disc for backups of data or video. Despite the many errors reported for each disc, none of them caused any problems to our BD readers and they were fully readable, which is quite encouraging.