DVD DL in detail

The DVD DL in detail

Both tables show the DVD DL characteristics and their competitors in pressed or DVD+R format. The DVD aspect has been developed with the intention of keeping the compatibility and the similarity with in one hand the DVD DL and the pressed DVD9 and in the other hand the regular single layer DVD. The data burning process is the same with the DVD+R DL as with the DVD+R and the +RW, they all use the lossless linking to keep no gaps between data. The track pitch is identical and has a 0.74 µm length. The track pitch is the distance between pits lines, measured from the centre of one line to the centre of the next line.



The wobble period is however raised of an additional 10% due to a more important channel bit length. In nanometre, the wobble period is the maximum amplitude of the pre-groove signal. The wobble period size change with the burner and the allowed burning method, because it determines the servo progression. The channel bit length represents the data density on the media. It is raised up to 0.146 µm on the DVD DL in order to improve the reading capacity and avoid interferences between the layer 0 and the layer 1.

The sensitivity is below the level of the classic 4.7 GB DVD+R. The classic DVD+R has a 4.5X density compared to the CD-R. The DVD DL only has a 4.X density compared to the CD-R. The whole capacity is connected to the density and fall from 4.7 to 4.27 GB by layer with a total of 8.55 GB for the DVD DL.

We also noticed that 30 mw of electrical power are required for the DVD DL compared to 19 mw for standard DVD. The gap is most likely due to the power loss due to the spacing layer and the first layer to cross. The burning speed for a DVD+R DL is currently 2.4 X.



When looking at the information of a blank DVD DL, we notice an 8.55 GB capacity and a DVD+R DL Book Type. The maximum burning speed is 2.4x or 3324 kb/s. The layer number is also indicated. However we also noticed that the DL media uses an OTP (Opposite track Path). So the burner starts in one direction on the first layer and continues in another direction on the second layer. In practice, the burner starts from the centre of the disc and goes to the circumference. And then immediately starts burning from the circumference of the second layer without coming back uselessly to the centre.

Reading compatibility

The reading compatibility

The DVD DL burning process is close to the classic DVD+R and the recording of pressed DVD9. The objective is the maximum reading compatibility. You have to be able to burn a DVD9 and be able to re-read it with a DVD-Rom and a DVD player. Is the objective reached? Well note quite.

In order to test the Dual Layer reading compatibility, we burned a disc with Nero Burning Rom 6 and tested it with several devices. It is a copy of the DVD movie Casino, initially a DVD9 integrally burned after ripping it via DVD Decrypter. It has to be said that copying a DVD9 is easier as it is not necessary to reduce the quality, remove the bonus or the different languages to put it on a DVD or a DVD+R.

Some of the DVD player only read the beginning of the DVD, so we checked the accessibility of the whole DVD. As it is possible to change the book type, we burned two DVDs for this test: one with the original bit setting in DVD+RW and the other with a modified bit setting in DVD-ROM. Liteon provide an utility to modify the medias boot type (before the +R burning) but it doesn´t work with the SOHW-832S. Fortunately, the bit setting module integrated to Kprobe works perfectly.

Changing the book type allow a better recognition of the media red, because some players base their ability to read a media only on the bit setting. If the player sees a code which doesn´t belong to its database it rejects automatically the disc. It happened frequently with media burned in DL. By changing artificially the book type it is possible to avoid this reject and gives a chance to the DVD player.

Reading compatibility, next

Reading compatibility, next

Here are the results obtained:

As shown, the possibility to indicate a "fake" book type helps with the DL media compatibility. Indeed, with a regular DVD+R book type, our DVD was compatible with only by 42% of the DVD-Rom players and 37% of the DVD+RW or –RW burner. The oldest DVD-Rom has some trouble with the DVD, and mostly the excellent old Toshiba which cant read the DVD+R DL, whatever the book type is. The Pioneer players give great results but not the burner. Amongst them only the DVR106S is able to read a DVD+R DL burned with a modified book type.

The compatibility with the DL media is slightly superior with DVD-Rom players than with burners, with 42% for DVD players and 37% for burners. However the burners have a high level of compatibility with a modified book type media. The compatibility is raised up to 64% and 62% for the DVD players.

We also notice the curiosity of the NEC2500 burner. Even flashed in 2510A (double layer burner), this burner can´t read the DVD+R recorded by the Liteon SHOW-832S. Fortunately, the 2510A flashed version is able to re-read its own DL media. In the other way around, the SOHW-832S is able to read the media of the NEC2510. And as we didn´t have an original and official NEC2510A, we were not able to check if the incompatibility came from the 2500A base components.

The assessment of DVD player compatibility is relatively good as 60% are compatible with non-modified DL media, this figure rise up to 90% with a modified book type media. Only the Panasonic SA-HT520 has rejected the media in both situations when cheapest DVD players accepted them. Of course this is a small test panel and the result isn´t representative and exhaustive.

Before starting frenetically to burn DVD+R DL (and with such expensive prices only a few will), you have to check if the DVD re-reading hardware is compatible.

The Liteon SOHW-832S

The Liteon SOHW-832S

The SOHW-832S is our first Dual layer burner tested. The first part of the name is a code related to the Sony Alliance Model ODD norm: SonyOptical Half Height optical loader DVD+/-RW. It has to be said that Liteon is now manufacturing the Sony burners, and the DRU700 is identical to the 832S apart from the personalised box.

The SOHW-832S is able to read CDs at 40X maximum speed and burn CD-R and CD-RW respectively at 40X and 24X. With the DVD+R and –R the speed is 8X and 4X for re-writing media + and – RW. The burning speed for DVD+R DL is currently limited to 2.4X. The access time to read a CD and a DVD is 160 ms. The Smart Burn technology is in charge of avoiding all errors due to the cache memory dumping. It also work with the CD burning and with the DVD+R and +RW where the lossless linking is 100% operational. However, the SOHW-832S is quite expensive.

Nero Info Tool indicates that the Le SOHW-832S has a RPC II zone protection with 4 possible changes. But Liteon provide a utility which transform the SOHW-832S in a RPC1 player without any zone restrictions.

DVD+R DL & DVD burning

DVD+R DL burning

A DVD+R DL is burned at 2.4X speed. So an 8.2 GB DVD requires 44 minutes and 50 seconds to be recorded with the lead in and lead out included. In Nero Burning Rom you will notice the bar indicating the 8.5 GB available with a blue bar for the layer 1 and a yellow bar for the layer 2.



As we only had Verbatim blank DVD+R9 for the tests, it was not possible to test the efficiency of the Liteon burner with any type of media. However we have observed the burning quality with Kprobe 2.1.

The test is made on the PIE (Parity Inner Errors) and the PIF (Parity Inner Failures). The figure obtained with the PI is accurate. However the 832 S Mediatek chipset doesn´t give directly the PO (Parity Order), but the Parity Inner Failures, which is quite different.

A PIE is notified when at least an error of one octet is found in one ECC block line. The tolerance for the DVD+R format is a maximum of 280 PIE in 8 ECC block consecutive lines. One ECC block line represents 182 octets. The last ten have the Parity Inner (PI). An ECC block has 208 lines and the last 16 have the Parity Order (PO) information. The most important information in the graphics is: if the average registered by Kprobe is low and if the PI max is superior to 280. It has to be noted that most of the time isolated peaks are a software mistake.

A PIF is a non correctable PI error. If an ECC block line include more than 5 octets, this line is considered non recoverable. In Kprobe, the maximum and average number of PO (as a matter of fact PIE) shouldn´t reach over 32. There again don´t trust isolated peaks not representative of the media condition.

A minimum PI and PIF error level has to be taken in account but is not essential as burned media with an error level beyond the limit aren´t inevitably unreadable. The main consequence will be a lower compatibility with players more demanding on the burning quality. It will also be red slower than another media with a higher burning quality level. But be careful, this measure is only one indication amongst others on the burning quality. The jitter and reflectivity are also two other elements to take into account.

First, the example of the result of a 3.6 GB pressed DVD (UT 2004).



Now the results provided by a Verbatim DVD+R DL with 8.2 GB of data burned with the 832S.



The maximum figure shouldn´t be taken into account as they correspond to the peaks observed on the two graphics. The PI level is slightly concentrated in the beginning of the disc, but is of one third of the maximum level authorized by the ECMA337 norm. Then the average is below 10 until the second layer and goes up again to 20. This result is excellent and quite flattering for the burner and the media.

The PIF (PO on the graphic) is also excellent wit a low average of 0.06 PIF. Altogether, the burned DVD figures aren´t far from the pressed DVD.

Even if the main innovation of the Lite-On SOHW-832S is the double layer DVD burning, it is also able to burn single layer DVD at 8X speed and for RW a 4X speed. In practice, and if you have the adequate media, burning a DVD+/- R take between 9mn12s and 9m34s with an average 6.8X speed. The RW media require 14mn30s at 4X.

CD burning

CD burning

The SOHW-832S is able to burn CD-R and CD-RW at 40X and 24X maximum speed. In CD-R mode the compatible speed are 8X and 16X in CLV and 24X, 32X and 40X in CAV. With an 80 minutes CD, the burning starts at 18.49X and finishes at 41.51X. The average speed observed is 31.46X. With a CD-RW, the 832S uses the Ultra Speed 24X in Z-CLV and 16X in CLV burning with the Ultra Speed media. It is also possible to burn in 4X CLV and in 10X CLV. Burning a 650 MB CD-RW in Ultra Speed 24X require 4 minutes and 10 seconds.



The average burning time at 40X for 80 minutes CD-R is a decent 321 seconds. The 832S is able to burn CD-R up to 99 minutes. The burning quality of Philips, TDK, Verbatim and Memorex media is good as no C2 error has been detected by Plextools Professional 2.14. The C1 error ratio is relatively low.

Below the results obtained with a 700 MB Memorex CD-R certified 52X.

Reading

Reading

The reading performances of the SOHW-832S are good. The bell-shaped transfer ratio curve has been obtained with the slightly below 8 GB media DL test. The reading orientation is inside-outside on the first layer and then outside-inside on the second layer. The two layer separation is represented by the vertical mauve line.



The average transfer ratio is 4.26X with a 6X top speed even though if the theoretical speed is 8X for DVD+R. Still with media DL, the access time is 107 ms with Nero CD-DVD Speed. This is a better result than the 160 ms announced by Liteon. However results are better when using a 4.5 GB single layer media with a 7.95X maximum speed. Apparently, the second layer penalizes the reading speed.



The DVD video rip speed via DVD Decrypter is excellent. The average speed is 8705 Kb/s or 6.3X. The result has been obtained with a firmware deactivating the rip lock. The Plextor PX-708A is restricted by the rip lock integrated to the firmware.

CD and DAE reading performances

The SOHW-832S is able to re-read CDs at 40X. With a CD-R 80 minutes Memorex the reading speed starts at 18.02X and finishes at 41.49X. The average speed for the whole CD is 31.31X. The average access time is 107 ms and is better than the figure announced by the manufacturer.



With audio extraction, the 832S has excellent results and fulfil all the advanced Nero CD-DVD Speed DAE Test requirements. The score is logically 100.0 and the averages extraction speed is 29.08X. The burner is able to read the sub channel information and the CD text.

NEC 2500A@2510A

NEC 2500A@2510A

The 2510A NEC is also a dual layer DVD burner and will be available from the end of June. With a more reasonable price than the SOHW-832S, it is considered as an interesting alternative choice. If you want to save even more money, you can choose the 2500A. This burner is identical to the 2510A without the possibility to burn DL media. However you can change it to a 2510A with a firmware downloadable here.

Be careful this firmware change cancels the guaranty! Thanks to the KOP2 firmware, the 2500A is changed into a 2510A, it also modify the player in a RPC1 (without any zone restriction) and deactivate the rip lock which prevent the burner from ripping DVD at 8X speed. As you can see below from the information obtained with Nero InfoTool after flashing it: the 2500 is indicated as a 2510A and the DVD+R DL reading and burning box are ticked.



Some burners aren´t DL compatible but can become compatible only by changing the firmware. However, even if these changes worked perfectly with our burner it is not always true. Depending on the series the KOP2 doesn´t activate functionally the DVD+R DL burning. Nothing to worry about but it is possible that you might not be able to burn DVD+R9. The official SOHW-832S or 2510A DL burner have been calibrated and tested as a DL burner. However the 2500 hasn´t been tested for DL and the calibration isn´t necessarily optimized. The efficiency of this new firmware is unpredictable for this aspect.

We have made the same compatibility and burning tests with a Verbatim DVD+R DL burnt by a 2500A flashed in a 2510A. The qualitative result is impressive as Kprobe report a PI and PIF average ratio below to the results of the Liteon 832 S with the same media. The reading compatibility is equivalent as the Liteon 832S. Even if, the NEC 2510A is able to re-read its own burned media (which is the minimum required).

Conclusion

Conclusion

The DVD+R Dual Layer burning make the DVD9 backup a lot more accessible. It is possible to store almost twice much more data than with standard DVD+R. This possibility is useful in a lot of different ways. 3.9 additional GB will be useful for videos as we will be able to rise up the quality and store longer videos.

Of course an expensive blank media is slowing down the DVD+R DL intensive use progression. But prices should change with the release of DL burners, and should fall in September.

The burning speed isn´t great either. In 2.4X you need 45 minutes to burn a DVD. But the manufacturer announce that they will reach 4X at the end of the year (25 minutes) and 8X during the second semester 2005. At this speed 15 minutes will be required to burn a DL DVD.

The remaining and tricky problem is the reading compatibility. Without modifying the book type it is inferior to 50% with computer hardware and barely 60% for DVD players. This figure is unacceptable and all the market players should develop adequate firmware when it is technically possible. The book type modification brings this figure with computer hardware to a very promising but insufficient 66%. And even if this modification isn´t too complicated, it is making the use of the Dual Layer media more difficult. We hope that this temporary operation will only be used in the future by owners of old hardware as a backup.

The final observations are promising even if there are still some compatibility issues. Being able to burn DVD+R DL is useful in a lot of ways, but you have to think about the possible uses and check the compatibility of the hardware use for re-reading.