While the HD multimedia playback technology has been on the rise, with more and better Blu-ray players and display solutions making their way from the drawing board out into the world, one element seems to have remained constant. The element of Blu-ray technology that has not seen any significant changes lies in the Blu-ray disks themselves. While much more capacious than DVDs, some companies seem to think that 25GB of optical storage is not enough. Sony and Panasonic seem to have developed a method to increase the data density of BR Disks from 25 GB to 33.4 GB.
This increase in per-layer storage capacity will be possible thanks to the Maximum Likelihood Sequence Estimation (i-MLSE) evaluation index, which will be able to properly evaluate the partial response maximum likelihood (PRML) signal processing. PRML assumes inter-symbol interference, an operation that does not exactly enable the quality evaluation of optical disks based on jitter.
"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," a source from Sony Corp. said.
The i-MSLE features two special traits. One is its very strong correlation with the error rate even in read/write at 33.4 GB using PRML, whereas the second trait is the fact that it "exhibits the same relationship to signal quality as conventional jitter." This makes the read error rate from the i-MSLE particularly easy to estimate, about as easy as that of the conventional jitter.
The first details on i-MSLE emerged at the International Symposium on Optical memory 2009 (ISOM '09), held in October 2009. Now that the technology is complete, Sony and Panasonic plan to propose the widespread adoption through the Blu-ray Disk association and other avenues.
It is unknown how long end-users will have to wait before the first 33.4 GB disks make it to the market, but what is known is that the technology will be compatible with all existing Blu-ray players, with the only requirement being a firmware update.