HD-DVD backers to add three-layer disk

TOKYO — Toshiba Corp. and Memory-Tech Corp. have developed a three-layered hybrid DVD/HD-DVD ROM disk that would enable the reading of two data formats on a single-sided disk.

The partners said they will propose the format to the DVD Forum and hope to make commercially available early next year.

In December 2004, the companies together proposed the DVD Twin Format, a single-side, two-layer disk to store both DVD and HD-DVD content. The format hit the market in April.

The twin format disk has the same structure as the two-layered DVD ROM disk. Two platters with a signal layer are bonded together and the signal is read from one side. The format promises to provide full compatibility between DVD and HD-DVD, and could help ease the transition from DVD to HD-DVD, Toshiba claimed.

"The third-layer Twin disk will provide another option to content providers to create attractive content for consumers," said Masato Otsuka, R&D director for Memory-Tech.

The newly developed hybrid disk has three layers. The DVD layer is closest to the pickup. The farthest layer is for HD-DVD content. The intermediate layer can be used for either DVD or HD-DVD content. Conventional DVD players can read the DVD layer.

The disk can hold a combination of 4.7 Gbytes of DVD content and 30 Gbytes of HD-DVD, or 8.5 Gbytes of DVD and 15 Gbytes of HD-DVD material.

"Content providers often want to have two layers to make an attractive disk with higher picture quality and high-fidelity music, multilanguage dialog and bonus tracks. With the third-layer Twin disk format, content providers can offer titles that are two-layer DVD with a bonus track, plus high picture quality movies in the HD layer, or DVD movies in the DVD layer and enriched content in HD-DVD," said Otsuka.

Otsuka claimed maintaining compatibility with the two-layered DVD and single-layer HD-DVD is relatively easy. While the reflection ratio of the HD-DVD layers drops in the twin disk, the partners intend to maintain it at 14 percent, the same level as HD-DVD rewritable disk.

"We proposed the disk format to the DVD Forum so that hardware manufacturers can prepare players and drives that can read such a disk," Otsuka said.

In May 2005, Toshiba announced development of a three-layered, 45-Gbyte HD-DVD ROM disk. The disk has not been submitted to the DVD Forum.

Memory-Tech already manufactures two-layered DVD twin disks, and has developed a disk manufacturing procedure that can add a third layer.

--中文大概的意思--
東芝(Toshiba)和Memory-Tech開發出一種三層混合(three-layered hybrid) DVD/HD-DVD ROM光碟，可以在一張單面光碟上讀取兩種不同的資料格式。雙方表示將把此光碟格式推薦給DVD論壇(DVD Forum)，並希望能夠在明年年初將之商業化。

早在2004年12月，這兩家公司就聯合推出了一種能同時儲存DVD和HD-DVD兩種內容的單面雙層光碟－－DVD混合光碟(DVD Twin Format)，並於今年4月上市。混合格式光碟和雙層DVD ROM光碟的結構是一樣的：具有一個訊號層的兩張碟片被接合在一起，訊號從單面讀取。東芝表示，這種光碟可以提供DVD和HD-DVD格式之間的全相容，並使從DVD到HD-DVD的轉換變得更簡單。

Memory-Tech研發總監Masato Otsuka指出：「三層混合光碟將給光碟內容供應商提供另一個選擇，來推出能吸引消費者的內容。」這種剛開發出來的混合光碟有三層。最上層為DVD層，最下層為HD-DVD層，而中間層則既可以用於DVD內容，也可以用於HD-DVD內容。傳統的DVD播放器可以讀取DVD層的內容。這種光碟有兩種儲存組合：一種是4.7G的DVD內容加30G的HD-DVD內容，另一種是8.5G的DVD加15G的HD-DVD內容。

Otsuka表示：「內容供應商總是希望通過雙層結構製作具有更高畫質、高保真音樂、多語言對話和額外軌道的光碟，來吸引消費者。現在，有了三層混合光碟，他們將可以在同一張光碟上提供帶額外軌道的雙層DVD和HD層高畫質電影，或者DVD層的DVD電影和HD-DVD層的豐富內容。」

另外Otsuka同時指出，要保持和雙層DVD及單層HD-DVD的相容性是相對容易的。儘管混合光碟中HD-DVD層的反射率有所降低，東芝和Memory-Tech仍打算將之保持在14%，和HD-DVD可複寫光碟的反射率相同。Otsuka表示：「我們會向DVD論壇推薦這種光碟格式，以便讓硬體製造商可以開始準備能讀這種光碟的播放器和驅動。」

2005年5月，東芝曾經宣佈開發出一種三層的45G HD-DVD ROM光碟，但並沒有將之提交給DVD論壇。目前，Memory-Tech已經生產了雙層DVD混合光碟，並開發出一種可以在光碟上增加第三層的光碟製造程式。