BD-ROM Region Encoding

[mito]

Is it known at this stage if BD-ROM will have region encoding like DVDs?

[Blu-Wave]

It hasn’t been decided yet whether BD-ROMs will be region-coded – although the studios are very keen on it, but unlike HD-DVD, Blu-ray has already chosen its encryption routine for BD-ROMs – using an AES 128-bit key that changes every six kilobytes, with technologies to prevent bit-by-bit copying and bus encryption for BD-ROM drives for PCs.

DVD encryption was defeated by DeCSS, but for Blu-ray, if one key is compromised the BDA can simply revoke that key, and only licensed Blu-ray manufacturers can make or copy Blu-ray discs.

[phloyd]

I was surpirsed to find out that D-Theater D-VHS has region coding - so the poor Japanese people with D-Theater capable players can't play the US tapes - instead, they have to select from the range of 0 (nil, nada) titles available!

Region coding is stupid and doesn't benefit the customer - it only benefits the studios.

So, expect it to be a 'feature'...! :roll:

Cheers!
DAve.

[Rob]

What will be the screen resolution of Blu-Ray pre-recorded media, especiaslly movies? I know that dvd provides 500 lines, (no idea how many pixels per line). But I have never seen mentioned what Blu-Ray will be. I know hi-def can be as much as 1920 by 1080. But I'm guesssing it might be more like 1366 by 768. Anyone know.

Also will there be more onformation allowed for the 5.1 soundtrack? if so will you need a new HC amp to play it?

[Blu-Wave]

Unlike red laser products, Blu-ray is capable of supporting several hours of "full" high definition resolution in high quality - that is 16:9 1920 by 1080 pixels progressive scan - also known as 1080p. As nearly all movies are recorded at 24 frames per second (except for IMAX HD which records 48 frames per second) support for a minimum of 1080p24 is enough to display high definition movies on BD-ROM. Some LCD displays are already capable of displaying 1920 by 1080 p60, with the higher frame-rates on the development path for high definition video (and Blu-ray).

To maximise quality with high definition, it is vital that there is a one to one mapping between encoded pixels on the BD-ROM and displayed pixels on the screen, so check the native resolution of any display you're buying for high definition if you want it to be "future proof." Broadcast high definition is normally at a lower 16:9 1280 by 720 pixels resolution progressive, to save bandwidth (and maximise revenue), known as 720p, and sometimes 720p60 is used for sports programmes. However, as films have an inherent framerate of 24 frames per second, 720p24 is all that is required. A possible solution for optimally displaying both 1080p and 720p material on the same display is discussed elsewhere on this site.

With MPeg2 at 24Mbps and compressed 5.1 audio (DD/DTS), a single layer 25GB BD-ROM can store around 2h 15m of 1080p24, with lossless DSD (SACD quality) 5.1 or PCM (DVDA Quality) 96kHz/24bit PCM 5.1 around 2h, with lossless 192kHz/24bit PCM 5.1 around 1h 30m, Mpeg4 FRExt at 16Mbps with DD/DTS 5.1 around 3h 20m, with lossless DSD or PCM 5.1 around 2h 40m, and with lossless 192kHz/24bit PCM 5.1 around 2h. These can, of course, be doubled by using a dual layer 50GB BD-ROM.

In comparison, an 8.5GB dual-layer DVD using Mpeg4 FRExt or WMV would, for the same quality with 1080p24 material, be able to store around 1h 10m, with lossless DSD or PCM 5.1 around 55m and with 192kHz/24bit 5.1 around 40m, and the figures for 15GB HD-DVD are around 2h, 1h 40m and 1h 10m, respectively. Therefore to get more than an hour or so of high definition video on DVD it is necessary to either accept lower quality or shift to a lower resolution – such as 720p24, for example, with less than half the number of pixels of 1080p24. :?

Coincidently, Microsoft’s online demos of high definition for DVD are generally optimised for 720p (at 1280 by 720 pixels) but appear to encode the vast majority of 1080p material at a resolution of 16:9 1440 by 1080 pixels, which is then scaled on display to 1920 by 1080! As a result, even if you have a 1920 by 1080 pixel capable display and computer you can’t gauge the quality of true 1080p24 material from 1440 by 1080 pixel demos. Also, even if the 1080p material was all true 1920 by 1080 resolution, comparing 720p material at a bitrate of 8Mbps to 1080p material at the same bitrate, 720p should look much better than 1080p, because with general material at least 12Mbps is required for Mpeg4 FRExt (which is very similar to WMV), and challenging material requires 16Mbps.

With half the number of pixels of 1080p24, it’s perhaps not surprising that 720p24 generally looks not unreasonable at 8Mbps with WMV – although even this appears not to be enough with “difficult” material – such as trees, desert, sea, sky, dust, scrubland and motion through natural environments in general. Perhaps the solution is for directors to refrain from including any natural objects in their films? MPeg4 FRExt compressed 1080p24 looks great at 8Mbps with computer generated imagery...

[phloyd]

Originally Posted by Blu-Wave

Broadcast high definition is normally at a lower 16:9 1280 by 720 pixels resolution progressive, to save bandwidth (and maximise revenue), known as 720p, and sometimes 720p60 is used for sports programmes.

Actually, most of the broadcast in North America is 1080i @ 30fps or 720p@60 fps.

1080i is two interlaced fields at 60 fields per second giving 30 full frames per second. CBS, NBC, UPN, PBS (OTA) and HBO, Sho, Starz, Cinemax, Discovery (Cable/Sat) are all 1080i broadcasters. So this is half the pixels/s of the elusive 1080p @ 60, though interestingly enough more pixels per seocnd than 1080p 24 which is ideal for films and is also one of the many ATSC standards.

ABC, ESPN and Fox are 720p at 60 frames per second (Fox will commence true HD next month).

I believe that Europe is tending towards 1080i @ 25 fps, but I have not seen any hard evidence of what is going on in Europe.

Cheers!
DAve.

[Blu-Wave]

As you say Phloyd, Europe has a 1080i channel - but in order to avoid certain spatio-temporal artifacts with interlaced signals, the effective resolution is roughly 1920 by 540 pixels at best - hardly what I would call high definition. :roll:

In the UK, BSkyB intend to start a high definition service sometime in 2006, but it's interesting that Fox is commencing true HD, as "Sky" are not saying a lot about what resolution the UK will get - 1080 or the semi-skimmed 720. Clearly, with the competition from pre-recorded 1080p24 software due to arrive in 2005, movie channels might favour 1080p24 whilst sports channels go for 720p60 or similar, but then you'd either need two displays or one which is optimised for both 720p and 1080p ...

Not quite sure how well all this fits in with region encoding, though - except in the sense of the resolution that the HD signal is encoded at...

[phloyd]

Personally, I think optimising for 720p is a waste of time 8)

Scaling 1.5x to 1080p is adequate for watching 720p (as long as you can handle 1080p @ 60).

Optimise for 1080p - it is the way of the future (for a while at least).

Cheers!
DAve.

[Blu-Wave]

Good point and I agree. 720p is an interim standard that, except for broadcasting, has a very small window of opportunity. As blue laser products have no problem supporting full 1080p24, which is all that is required for the vast majority of films, it would make a lot of sense to go for a high quality 1080p display if you can afford it - or wait a little if you can't. 720p displays will very quickly become obselete once high definition pre-recorded material arrives en masse, whilst 1080p will be the home standard for quite some time.

If this MPeg4 FRExt thing works out, a 50GB BD-ROM could store around 9 hours of typical films in high quality with DD/DTS 5.1, or 6 hours 30 minutes with lossless SACD [DSD] 5.1. A display which supports 1080p60 could use future high definition 1080p60 discs, which would equal around 6 hours of typical films with DD/DTS 5.1 or 4 hours 20 minutes with lossless DSD 5.1.