A new method of evaluating Blu-ray Disc media quality could increase the per-layer storage capacity of a BD discs from 25GB to 33.4GB. The new method is likely to accelerate development of discs offering even more storage space.

Read and write at 33.4GB per layer would be implemented thanks to the use of partial response maximum likelihood (PRML) signal processing, reports Nikkei Electronics Asia. The new method can continue to accommodate the existing Blu-ray optics: a blue-violet laser diode with a 405 nm wavelength, and an object lens with a numeric aperture (NA) of 0.85.

The problem until now has been there was no evaluation technology appropriate for 33.4 GB media using PRML. PRML assumes inter-symbol interference, which makes it difficult to base optical disc quality evaluation on jitter, as is widely done now for Blu-ray and many other optical discs. A source at Sony states, "At high-density recording, such as 33.4 GB, the relationship between the error rate and jitter collapses, and it becomes extremely difficult to evaluate jitter."

Sony and Panasonic resolved this by developing the i-MLSE (Maximum Likelihood Sequence Estimation) evaluation index. Details of i-MLSE were announced at International Symposium on Optical Memory 2009 (ISOM '09), held in October 2009. The first of the two key characteristics is that i-MLSE has a strong correlation with the error rate even in read/write at 33.4GB using PRML. The second, according to Sony, is that "i-MLSE exhibits the same relationship to signal quality as conventional jitter." In other words, it will be relatively simple to estimate the read error rate from the i-MLSE, just as can be done now with jitter.

The problem with i-MLSE is that calculation is complex. With recent hardware advancements, though, says Sony, "It should be possible to process in real time, just like jitter."

Sony plans to propose widespread adoption of i-MLSE via the Blu-ray Disc Association and other avenues. Sony is a core member of the Association, making it likely that i-MLSE will be adopted as a standard.

The increased capacity of Blu-ray media will help with the storage demands of 3D movies such as 'Avatar'. Sony is planning a line of 3D televisions, which ties in with the whole idea that 3D technology will strengthen sales of high-definition televisions, disks and media drives.

For example, it has announced the BDV-HZ970W home theatre system at CES, which includes an integrated 3D Blu-ray player. It has also announced a standalone 3D Blu-ray player, the BDP-S770, which should be available in the summer

Story filed 09.01.10