1080p??

[Kitsunebi]

I never read any decisive statements on whether or not Blu-ray will sport 1080p resolution. Considering there are LCOS and soon DLP displays that will be 1080p native, it would kind of stink to end up with 1080i Blu-ray movies.

Considering the rather large capacity compared to AOD, one would think it's doable?

[Blu-Wave]

35mm film operates at 24 frames per second, and one of the HDTV modes is designed to display this precisely - cinema or film mode. Provided that the display device updates on transitions (instead of periodically refreshing and fading between refreshes like a conventional CRT), there is no reason why flicker should be an issue, and the relatively low frame rate (24Hz) keeps data storage and transfer requirements down at interlaced levels.

The intention is for Blu-ray "film" releases to support this dedicated film format - getting the most from HDTV. Note that many current "High Definition Capable" displays are, unfortunately, not... :!:

[phloyd]

24 fps at 1920x1080p is part of the ATSC standard. So is 24/1001 = 23.976 fps progressive.

Also, WMVHD seems to be focused on 1080p @ 24.

There is a good chance that film discs will be capable of this format.

Also of interest, many movie DVD's are currently encoded at 24 fps progressive with pulldown flags to output 29.97 interlaced.

I believe that HBO and Shotime both broadcast their HD content this way also. So, it seems that it should be fairly easy to support both 24 and 29.97 output from the same disc.

Cheers!
DAve.

[Kitsunebi]

I guess this means the real question is if Blu-ray movie disk will support WMV or a similar level of compression to do 1080p/24fps. I haven't done the math for MPEG2, but I get the notion that it'll still be too big.

Also of interest, many movie DVD's are currently encoded at 24 fps progressive with pulldown flags to output 29.97 interlaced.

Ahh, I didn't know that! This would mean that an animator could only worry about rendering their content 1080p at 24 fps and not have to render out interlaced frames (which would require those with 1080p displays to use a deinterlacer).

Thanks guys!

[Blu-Wave]

Sony's original Blu-ray recorder (the BDZ-S77) supports both 1080i and 720p @ 24Mbps using MPeg2, which for NTSC is:

1280 by 720 pixels @ 60 frames per second, or
1920 by 1080 pixels at 60 fields per second (30 frames per second).

...which at similar compression ratios both equal around two hours recording time on a single layer 27GB disc (or four hours with the new dual layer recorders and 50GB discs).

Note that 1920 by 1080 pixels @ 24 frames per second is actually less raw data than 1280 by 720 @ 60 frames per second! :!:

[zombie]

I highly doubt any HD disc format will support higher than 1080i in the next several years.

[Blu-Wave]

Mass-market films - even digital fims - are produced at 24 frames per second. 1080p24 requires no conversion processes, simply a display that can update at 24Hz without flicker (i.e. not a CRT, for example). 1080i (at 50 or 60 fields per second, two fields per frame) not only involves more data than 1080p (at 24 frames per second), but significant conversion artifacts (from film's 24 frames per second). Another minor drawback of interlacing is that, in order to avoid spatio-temporal aliasing between fields it is necessary to significantly reduce the vertical resolution, compromising the quality of the output. :?

1080p24 makes more sense than 1080i for quality and simplicity (from film), for basic data-rate (80% of the data-rate of 1080i60), for compression (both intra and inter frame) and for high definition (avoiding the temporal aliasing filters required by 1080i), provided that the display device can handle the 24Hz frame rate (updating on transitions rather than refreshing and fading like a CRT...

[Kitsunebi]

While the logic behind 1080p/24 bandwith is sound, I'm afraid 720p-san might be right. I'm having a hard time finding any official word anywhere of any industry support for consumer level 1080p support in this medium.

1080i is basically for CRTs. I much prefer a lower rez and progressive format than anything interlaced, if it can be helped. I'd like to see 1080p disks for those 1080p displays. If nither Blu-ray or AOD plan on supporting 1080p of any sort then I'll have a hard time in getting or recommending those new and upcomming 1080p displays because it would only be a practical joke if there is no 1080p content to speak of.

Now, we arn't going to get TV screens to "refresh" at 24Hz (you can only get away with that with reel projectors), but there is nothing wrong with displaying the same full frame for a couple of cycles aside from making the disk player smarter, I would think.

But hey, TDK made a quad layer blu-ray disk in their labs that can hold 100 gigs, I heard... maybe there's hope for 1080p/60 content yet! :lol:

Seriously though, has anyone heard anything official on this matter?

[phloyd]

I wouldn't call this at all official, but I know that 1080p displays are being developed.

I also know that 1080i line doubled to 1080p looks pretty good and IMHO looks better than 720p scaled up to 1080p.

DVD's and HBOHD/ShoHD in the US currently are encoded at 24 fps progressive with pull down flags for conversion to interlaced output.

1080p at 24 fps is one of the ATSC standard resolution/frame rates.

For 24 fps sources, a display running at 120 fps can show 24 fps at 5x and 30/60 at 4/2x. This is where the "who goes first - content or display?" question will come in to play. Who will make the first effort?

So there is hope. The question is whether the content providers want to let the 24 fps progressive signal out ... and will displays understand it?

It can't hurt to make it an option...???

Cheers!
DAve.

[Blu-Wave]

As Phloyd pointed out, standard 35mm films are made at a frame rate of 24 frames per second, leading to DVD's etc. being encoded at 24fps and then converted for display in PAL (50i) or NTSC (60i). For maximum quality and minimum artifacts it would therefore make sense to be able to display films in the same format as they are encoded (1920 by 1080 p24) or a multiple of 24 - such as the 120fps he suggested.

It will probably be some time before a new spatial resolution standard beyond 1920 by 1080 is developed for the home, but Sony are actively researching the benefits of higher frame-rates (i.e. higher temporal resolution) - such as seen in IMAX (which also has much higher spatial resolution than HDTV). If displays such as the (24fps by 5) 120fps one mentioned by Phloyd can handle it, this might be a way we can go in the future without having to replace our displays yet again.

[Kitsunebi]

A change in framerate probably wont require a display upgrade as a significant change in resolution would, but let's not get ahead of ourselves. :wink:

I we know 1080p displays are offically being made. Toshiba's 57HLX82 is a 1080p LCOS screen. The Samsung HL-P6197W ($6,499 MSRP for November) will be a 61-inch 1080p DLP utilizing Texas Instrument's tentatively named "xHD3" DMD chip which was shown off at this year's CES in January (notice the "1080p DLP TV" on the upper left of this display). While an 800x600 JPEG photograph isn't going to remotely do 1080p justice, they do claim contrast ratios of 5000:1 and the press seemed to be impressed enough with the blacks. There were also some rather large Plasma and LCD displays with 1080p natural resolutions being unveiled, but some of those are likely a ways off yet.

It seems the displays arn't wasting too much time going 1080p. It would be silly for 24fps progressive content to be forced to pull down simply to be de-interlaced to be displayed on a 1080p monitor anyway. Of course, having progressive content with the pulldown flags is a good way of future proofing that content, which is why I'd want this media to be 1080p, because the 1080i/720p people get what they'd normally see and the 1080p users will get what they paied for.

I also heard through the grape vine that 1080p is indeed the goal for HD-DVD, but I don't know if they were just talking about AOD or both AOD and Blu-Ray as I do not have any issues of HDTV etc which was allegedly the source of this information.

[Blu-Wave]

Talking of HD-DVD, its proponents are working hard to reduce the head-size in order to achieve 60GB dual-layer double-sided. But this is likely to be problematic. Even dual-layer rewritable is causing some problems at the moment.

In contrast, Blu-ray was designed from the outset to support multi-layer recording, and TDK have already demonstrated 100GB four-layer recording, so 200GB double-sided is already possible. It would make a lot of sense for Sony etc. to continue working to reduce headsize and then provide support for double-sided recording - at least in higher end computer applications and then later on 24GB dual-layer double-sided High Density Minidisc [HDMD].

For more details see the Blu-ray vs AOD vs HD-DVD thread...

[zombie]

As nice as 1080p sounds, do the Blu-ray group or HD-DVD org really want to alienate all of the people who already have HDTVs which are only capable of 1080i? It wouldn't be a very wise decision. IMO they'll wait several years and then perhaps release 1080p HD discs and hope HD-addicts will upgrade to the next format. I personally think 1080i discs are the best we're gonna get for awhile.

[Blu-Wave]

As Phloyd said, current DVDs are typically p24, with pull-down flags to support interlaced output, etc., and there's no reason why HD discs can't offer native 1080p24 with pull-down flags for 1080i and scaling for 720p - as they're all part of the high definition standard it'd make a lot of sense. However, 1080p24 will minimise the number of artifacts as it involves no conversion processes from the original film apart from A/D (ignoring the substantial amount of compression required, of course). :?

Talking of compression, MPeg2, as well as being less efficient than MPeg4, produces much more noticeable "blocky" artifacts. MPeg4 would allow a data rate of below 20Mbps on the disc, which would support higher quality audio when available - such as in live concerts, for example. We could have SACD/DVDA192 quality surround sound coupled with high definition video.

[phloyd]

Yeah, HBO HD already broadcasts this way and nobody notices because they see 1080i coming out of the set top box...

I think that in the same way that DVD supports DD, PCM and DTS, there is no reason that BDVD can'r support a range of video codecs - one or two as mandatory support (MPEG2 would be mandatory) and others as optional.

MPEG4 or WMV could help give better quality with the same bit rate or similar quality with lower bit rate.

Personally, I want to see maximum quality. We "suffer" every day with so called HD broadcasts with 10-14 Mbps with blocking and other artifacts galore ruining the image...

That said, the DTheater DVHS tapes look pretty stellar at 28 Mbps...!

Cheers!
DAve.

[Rimmer]

Originally Posted by phloyd

Yeah, HBO HD already broadcasts this way and nobody notices because they see 1080i coming out of the set top box...

So there is no pre-filtering on broadcast 1080i film material, or on D-Theater tapes? That's how it should be anyway: encode without filtering, then let the STB perform any necessary filtering for interlaced output. Otherwise no one will ever get to see the full vertical resolution on their progressive displays, as is the case with current DVDs.

[Blu-Wave]

Just because it's 1080p24 doesn't mean that it isn't prefiltered to roughly 540 to suit 1080i - although to say that it wouldn't make a lot of sense would be a bit of an understatement. ...then again, if DVD can do it... But the whole point of high definition is to provide cinema-like resolution - 1920 by 1080p24. As new displays are required for HD anyway, they wouldn't make the DVD mistake again when 1080p24 will be the preferred resolution and fully HD-compatible displays will be designed around HD instead of fifty year old broadcast standards. Would they? ops:

On a related note, second generation 50GB dual-layer Sony Blu-ray recorders have a four hour HD capacity at 24Mbps total data-rate. Professional Disc for Data [PDD] supports double the data-rate of standard Blu-ray (i.e. 72Mbps instead of 36Mbps) and Sony XD-Cam video recorders are available which use two heads to achieve 144Mbps. If up to 72Mbps was used instead in Blu-ray, a video data-rate of 28Mbps or higher could be supported along with high resolution audio yet still achieving, say, three hours of HD recording. ...and well implemented 28Mbps MPeg4 looks similar to if not even better than 56Mbps MPeg2. It may even be possible to have a head which reads and writes both layers in parallel...

It would also push 50GB Blu-ray HD film quality beyond the bounds of a single dual-layer 30GB HD-DVD disc... :wink:

[phloyd]

Here is an interesting article about 1080p.

Cheers!
DAve.

[Blu-Wave]

Interesting Phloyd. Of course, 1080p24 produces a lower data-rate than 720p60 anyway - which would be great for transmitting pre-recorded films, and MPeg4 is certainly capable of getting 1080p60 down to MPeg2 720p60 data-rates without losing quality. Talking of higher frame-rates, the object-orientated way that MPeg4 operates makes it much more efficient in this regards than MPeg2, and minimises artifacts, and beyond 100 frames per second or so the additional bandwidth required to record a typical sequence drops dramatically. However, larger buffers may be required to cope with the more dynamically variable data-rates... :?

[Blu-Wave]

Interesting Phloyd. Of course, 1080p24 produces a lower data-rate than 720p60 anyway - which would be great for transmitting pre-recorded films, and MPeg4 is certainly capable of getting 1080p60 down to MPeg2 720p60 data-rates without losing quality. Talking of higher frame-rates, the object-orientated way that MPeg4 operates makes it much more efficient in this regards than MPeg2, and minimises artifacts, and beyond 100 frames per second or so the additional bandwidth required to record a typical sequence drops dramatically. However, larger buffers may be required to cope with the more dynamically variable data-rates... :?

I could swear I was seeing double there...