News about blu-ray

[osvaldomartins]

I found this in some japanese sites but I was not able to translate it. It seems to be something about an update of the blu-ray movie speed read to 40Mbits (despite of the 54Mbits) but im not sure.

If somebody could help me and translate it, I´ll be pleased!!!


IFA：ソニーがBlu-ray Discの最新デモ、40Mビット/秒の映像再生など

2005/09/07/

ソニーは「IFA2005」で、同社が推進しているBlu-ray Discの最新デモンストレーションを披露した。

今回初めて見せた機能は2種類ある。1つめが、高い符号化データ速度への対応。Blu-ray Discの規格では、読み取り専用のBD-ROMの符号化データ速度は54Mビット/秒、そのうち40Mビット/秒を映像が利用できることになっている。今回は、この上限の映像データを再生できることを示した。デモンストレーションにおける動画像圧縮の符号化方式にはMPEG-2を採用した。この処理に用いたハードウエア構成は明らかにしていない。

 

[BlueTsunami]

IFA: SONY the up-to-date demonstration of Blu-ray Disc and 40M bit per second image playback etc. 2005/09/07/ SONY with "IFA2005", announced the up-to-date demonstration of Blu-ray Disc which the same company has propelled. As for the function which this time was shown for the first time there are 2 types. 1 stuffing, correspondence to high coded data rate. With the standard of Blu-ray Disc, and the coded data rate of read-only BD-ROM 54M bit per second, 40M among those bit per second has meant that image can utilize. This time, the fact that the image data of this upper limit can be played back was shown. MPEG-2 was adopted to coding system of the dynamic picture image compression in demonstration. The hardware constitution which is used for this processing has not made clear.

Its to early to read japanese tranlated into english...I don't need a headache

 

[Arnie Pie]

I interpret that as saying that they've demonstrated playback of an MPEG2 stream with a sustained 40Mb/sec bitrate, from standard BD-ROM media (with a theoretical maximum rate of 54Mb/sec). That's a large bitrate for video only, with the lower bitrate probably being caused by the fact that 54Mb/sec is achievable only on the outer edge of the media.

They go on to say that they've not disclosed what hardware was doing the decompression.

 

[RavenFox]

So...this is good news then?

 

[Shifty Geezer]

I read it as 54 mbps from read-only media, and now 40 mbps for standard (rewriteable) media. Don't think it brings anything new to BluRay for PS3.

 

[Mefisutoferesu]

I remember reading something a while back where Sony or some member of the Blu-ray group were working on a method to increase writing speeds to 72mbps... do you suppose the 40mbps is the fruit of that effort?

 

[Guden Oden]

with the lower bitrate probably being caused by the fact that 54Mb/sec is achievable only on the outer edge of the media.

That's not a fact at all. Ever heard of CLV? That's the scheme used by audio CDs and DVD movies to acheive constant datarate across the entire surface of the disc - the spindle spins faster while reading from the center portion, and slower towards the edge.

 

[Arnie Pie]

That's not a fact at all. Ever heard of CLV?

Yes.. of course I have heard of it. I've been writing streaming systems for games for the last 10 years.

Although there's no information to say whether this demonstration was performed with CLV or CAV, I was merely speculating that the reduced (ie 40 vs 54) rate may be due to a CAV mechanism.

 

[Bobbler]

40mbit/s is what it takes for 1080/24p video. 48mbit/s is the max bit rate for mpeg-2 video (apparently). The rest of the bandwidth can/will be used for sound (the extra ~14mbit/s).

These numbers have been in the PDFs for a long time now. Nothing was lowered or changed.

 

[phat]

I think the article is saying that 40Mb/s of the 54Mb/s is apportioned to video. The remainder would be for things like audio, subtitles, whatever else they want to subcode into the stream.

 

[Nicked]

Source?

 

[osvaldomartins]

"Source?"

http://nikkeibp.jp/wcs/leaf/CID/onair/jp/jp_print/396178

 

[Guden Oden]

Yes.. of course I have heard of it. I've been writing streaming systems for games for the last 10 years.

Well, so you say anyway.

Although there's no information to say whether this demonstration was performed with CLV or CAV, I was merely speculating that the reduced (ie 40 vs 54) rate may be due to a CAV mechanism.

It wouldn't go down to just 40mbit/s if it was CLV, the large diameter of an optical disc would ensure read speed would be significantly lower at the centermost portions at a fixed rotational rate. Less than 50% of outer edge speed shouldn't be an extreme guess IMO...