We had a presentation from Pioneer yesterday about their position on BluRay. A few interesting and somewhat concerning points came out of it.

1: He said there is no support for 720p, only 1080i and 1080p. With 1080p diplays being pretty rare and not likely standard in homes for many years to come the only way to diplay 720p footage is via converting it to 1080i. If true this seems to be something to be concerned about.
*Edit: Seems this is NOT true, see later post.

2: 1080i/p MPG2@HL for BD-AV is a short GOP format so both 720p and HDV 1080i will require recoding. No direct burn to disk and play support.

3: Consumer/Semi-Pro authoring software may not support authoring anything but MPG2@HL. Apparently these high compression codecs are not seem as ones BluRay want to really see on their media.

Other stuff said to but not related to the 720p issues which relate this post to this forum.

Anyone got any evidence to contradict/correct the comments made to us last night?

PS: Pioneer will be releasing a drive at the end of the year with Dual Layer BR burning support, but are in no hurry as there is really no software to author with yet anyway.

There's nothing wrong with encoding the material at 1080p- it would make a lot more sense than going 1080i. Set-top players will be able to convert to 1080i or 720p on-the-fly during playback if necessary- this is how all HD-DVD and Blu-Ray movies will be handled- the discs themselves are/will be encoded at 1080p 24fps.

Also- I wouldn't worry about having to work with short GOP, remember that you'll be able to work with multi-pass VBR methods when authoring, which should allow plenty of headroom and yield some fantastic results. Also- even though consumer-level software won't see them initially, expect to see VC1 and AVC encoding options showing up as time progresses. You have to bear in mind that the BR/HD-DVD are in their infancy. Much progress will be made with a little passage of time.

It doesn't make a lot of sense to me to:

Capture in 720p
Resample to 1080p for burning
Resample back to 1080i or 720p for playback.

If the formats simply supported 720p all this format conversion wouldn't be required, quality won't be lost or data won't be wasted encoding upsampled video for no good reason. Conversions are nice in theory (just convert from A to B to C to D and your done!) but to doing all these conversion, and some in RT is going to effect the image you see on the display.

Seems like a horses ass aproach to me. Is this just Sony sticking the finger at JVC and 720p. Given HD-DVD doesn't support 1080p (I think), does it support native 720p material?

I don't want to make this a BR vs HD-DVD thread, I am only intersted in looking at it from a workflow and quality of output of material you will have with the JVC cameras. What is the best option going to be in the short and long term (these may be different)?

To not support 720p is bonkers. To force people to upconvert to 1080p just wastes bits, and of course, I bet the 1080p doesn't offer 60p support which is what you'd need for 720p60 upconversions anyway. To convert 720p60 to 1080i60 is a step backwards to the nasty evil land of interlace. What a botch job this HD revolution really is.....

Graeme

Unless there's collusion or it's not in the spec, there will be a Blu-Ray Player manufacturer that will make a player with 720p playback. They will bury the competition if they market it aggressively.

Is this a Sony 1080i conspiracy?

I think we can all rest a bit easier and I need to correct this Pioneer rep:

http://www.blu-raydisc.com/Section-13470/Section-13627/Index.html

Video highlights
The BD-ROM format for movie distribution supports three highly advanced video codecs, including MPEG-2, so an author can choose the most suitable one for a particular application. All codecs are industry standards, meaning easy integration with existing authoring tools, and choice from wide range of encoding solutions. All consumer video resolutions are available:
- 1920 x 1080 HD (50i, 60i and 24p)
- 1280 x 720 HD (50p, 60p and 24p)
- 720 x 576/480 SD (50i or 60i)

Sorry for the scare.

Thanks Guy! That's good info,

and yes, it's a Sony 1080i (we're still living in the 30s) conspiracy.

Graeme

no SD 50/60p support though :-(

It doesn't make a lot of sense to me to:

Capture in 720p
Resample to 1080p for burning
Resample back to 1080i or 720p for playback.

First of all- it's good to hear that 720p will be an encoding option from day one. Having more options is always a good thing.

Beyond that- it's still really not a big deal at all to be up or down sampling between the various HD formats. Displaying 1080p as 1080i on an HDTV (performed either in software during authoring, or live from the player's output or the TV's own video chip) is as simple as adding artificial fields- it won't degrade the image at all because the source is still progressive and there's not going to be any inter-field motion. Also- any HD display or player is going to handle 720p<>1080i conversion very well, which is good because that upconversion will have to be applied on the fly by either the player or the display whenever our 720p-authored discs are viewed on 1080i or 1080p sets.

Being able to work in 720p straight through makes things easier for us as content authorers, but it really won't affect the final quality of the viewed product. If we're going to get hung up over up or down conversion- the only instance where a 'pure' viewing experience would be taking place woulde be when our disc authored at 720p is viewed on a native 720p display.

Given HD-DVD doesn't support 1080p (I think), does it support native 720p material?
Just FYI- HD-DVD offers full 1080p on-disc support. All of the current HD-DVD movies on the market are encoded at 1080p 24fps. The early players out now are only offering 1080i output, but there's no limitiation on 1080p as far as the HD-DVD spec itself is concerned.

You can always record over the SD DVD if you need to have your project in progressive. We shall see if the debut of Blu-Ray overshadows HD-DVD. Blu-Ray offers higher resolution, but HD-DVD offers a lower price. I believe (like many others) that waiting to see who the winner of the format war is the best option. SD DVD will most likely continue to be the overall winner for years to come though. The difference in quality and low price of DVD will be the most difficult obstacle for both Blu-Ray and HD-DVD to overcome.

Or maybe the world should ignore HDDVD and BluRay totally and just use ordinary DVD discs and Progressive players with WMVHD or DIVXHD, it's looks great on a 720P LCD screen and serves it's purpose for the end user, I really do wonder why the world really needs BluRay and HDDVD, I mean how long is it till they will be in every house ? a huge number of computers can already run WMVHD and DIVXHD, you can easily buy players for the home that do the same at regular prices, why spend a fortune on a new player that is going to be in a format war, I think Both BluRay and HDDVD could be losers long term if luck is not on there side, by the time they are popular enough to be cheap units people could be begging for 2K in the home.

You guys make some good points, but there are probably better places on the net to have the Blu-Ray vs. HD-DVD vs. DVD debate.

You are right Jake. This could easily set off a format war discussion, but the most important aspect of Blu-Ray and HD DVD for us is not to replace DVD, but to have the ability to show HD recordings on the highest possible quality for mass or minimal distribution.

You are right Jake. This could easily set off a format war discussion, but the most important aspect of Blu-Ray and HD DVD for us is not to replace DVD, but to have the ability to show HD recordings on the highest possible quality for mass or minimal distribution.

And Archiving.

HD-DVD supports h.264 which pretty much eliminates the size/storage advantage of BlueRay, which doesn't. H.264 is the future for broadcast HD too.
If you don't have hdcp, you only get half rez from either type. More importantly it will probably be one of the preferred codecs for streaming over the internet. I've seen some 720p stuff from IM.com and though the content sucked, the picture quality was great.

I went and saw true 1080i from a 1080p source (HD-DVD) in an upscale home theater store. It was outstanding. And there is a lot of life left in 1080i, for things like reality shows and such.

I agree waiting until things sort out.

Wow, Joe- I'm sorry, I know I was the one saying that this was not the place to be having serious BR/HD-DVD discussions, but I need to clear some things in your post up before people get the wrong idea.

HD-DVD supports h.264 which pretty much eliminates the size/storage advantage of BlueRay, which doesn't. H.264 is the future for broadcast HD too.

This is misleading- the Blu-Ray spec supports H.264 and VC1, just like the HD-DVD spec. All Blu-Ray players will offer hardware decoding of H.264 and VC1 content from day one. It's true that the first BR discs are going to be MPG2, because the BR camp hasn't incorporated H.264 or VC1 into their authoring toolkit as of yet, but they are both inherently incorporated in the Blu-Ray spec, and will be included in the authoring toolkit before year's end.

If you don't have hdcp, you only get half rez from either type.

This is not true at all. The studios have completely backed away from using the ICT (Image Constraint Token) flag, which is what would have caused downrezzing of material over a component connection. None of the movie releases for either BR or HD-DVD are expected to incorporate ICT over the next several years.

Okay, I checked some other sources and I am wrong, they do support h.264, it's sony itself that is not supporing h.264 on their releases.
I remember reading several news stories and press releases about the big fight between MS and Sony over not supporting VC-1 and not supporting copying to a home theater server. Now I can't find them.

Okay, I checked some other sources and I am wrong, they do support h.264, it's sony itself that is not supporing h.264 on their releases.

You might also want to check out the "High Definition DVD Players" section over on highdefforum.com. No news pertaining to the new formats gets by that forum without being reported.

Thanks, I'll do that, Now I have to figure out how to make quality vc-1 with surround sound for delivery. And find those articles, hehehe.

I remember reading several news stories and press releases about the big fight between MS and Sony over not supporting VC-1 and not supporting copying to a home theater server. Now I can't find them.

All of the BR players have VC1 compatibility as part of their published spec for hardware decoding upon playback. If you look up the tech specs for the forthcoming players from Sony, Samsung, Pioneer or Panasonic, you'll see VC1 support in the list. As for whether or not Sony will ever implement it on the discs themselves due to "political" differences with MS is another matter. Only time will tell. H.264 is a sure bet though.

Thanks, I'll do that, Now I have to figure out how to make quality vc-1 with surround sound for delivery. And find those articles, hehehe.

If you have the huge capacity of BR, I can't see much reason to use anything but MPEG-2. The newer codecs make lots of sense for putting HD on red-laser DVDs, but with BR and 35Mbps -- why worry use a MS (or Apple) product and go out onto the bleeding edge. That's the reason the films coming-out are MPEG-2. We know how to do it well.

As far as MPEG-4 being the "future Broadcast codec," there is zero movement to include it in the USA's ATCS standard. Every DTV unit in the ATSC world would have to be tossed and rebought. Not gonna happen in this decade!

Ditto for cable boxes. Only DBS finds it cheaper to go with new boxes -- which customers may be forced to buy -- than put up more satelites.

Hi Steve. We've been doing alot, and I mean alot, of research on the jpeg2000 codec, especially with our probable acquisition of 2 GV Infinities for on-hand cameras later this year. Have you looked into the codec and if so, perhaps you can tell us what your thoughts are.
Jonathan

. Displaying 1080p as 1080i on an HDTV (performed either in software during authoring, or live from the player's output or the TV's own video chip) is as simple as adding artificial fields- it won't degrade the image at all because the source is still progressive and there's not going to be any inter-field motion. Also- any HD display or player is going to handle 720p<>1080i conversion very well, which is good because that upconversion will have to be applied on the fly by either the player or the display whenever our 720p-authored discs are viewed on 1080i or 1080p sets.

Jake - I wouldn't be too sure of this - the scalers built into most HD sets and projectors (except for some very high end models) are cheap and do an exceptionally poor job of rescaling video. They generally introduce a lot of MPEG artifacting and artificial edge enhancement that is not present in the original image - especially when compared to something like a DVDO iScan. Quite often they don't even include a decent quality de-interlacer resulting in jerky motion from interlaced sources on a progressive screen.

I for one am exceptionally relieved to hear 720P will be supported - not to do so would be crazy given the vast array of native 720P displays on the market.

If you have the huge capacity of BR, I can't see much reason to use anything but MPEG-2. The newer codecs make lots of sense for putting HD on red-laser DVDs, but with BR and 35Mbps -- why worry use a MS (or Apple) product and go out onto the bleeding edge. That's the reason the films coming-out are MPEG-2. We know how to do it well.


Steve I couldn't agree more - the attraction of the newer MPEG 4 codecs like H264 is for low data rate applications where they excel - but as you throw more and more bits at your source the difference between MPEG4 and MPEG2 becomes negligible. Why would you want to use anything else but easy to encode high quality MPEG2?

Now I have to figure out how to make quality vc-1 with surround sound for delivery.

You might start by reviewing the following links:

http://www.microsoft.com/windows/windowsmedia/forpros/content_provider/wmvhddvd/default.aspx

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwmt/html/introduction_to_hd_dvd_authoring__codz.asp

HD-DVD supports h.264 which pretty much eliminates the size/storage advantage of BlueRay, which doesn't.


I actually don't care who wins the video playback war, BUT
for archiving purposes Blu-Ray will win imo strictly for the ability to store much more information right off the bat.

The day a 50gb dual layer BDR drive is available and can burn data on my Quad G5 edit system, I'm gettin it. :)

Jake - I wouldn't be too sure of this - the scalers built into most HD sets and projectors (except for some very high end models) are cheap and do an exceptionally poor job of rescaling video. They generally introduce a lot of MPEG artifacting and artificial edge enhancement that is not present in the original image - especially when compared to something like a DVDO iScan. Quite often they don't even include a decent quality de-interlacer resulting in jerky motion from interlaced sources on a progressive screen.

This is really untrue- and you should be glad that it is. Conversion between 720 and 1080 signals is handled very, very well by the overwhelming majority of HD displays. Professional reviewers don't even bother exploring this aspect of an HD display anymore because the best processes for conversion between the two HD formats was ironed out five or six years ago. The problems with interlace tearing and artifacting that you mention above are more indicative of what happens with most HD displays when trying to upconvert to HD from standard def- that's a very different ball of wax. Bearing in mind that the majority of HD broadcasts are in 1080i- if what you're saying were true, the manufacturers of 720p displays would have a pretty hard time selling them. The reason they haven't had problems, though- is because 1080i is handled very, very well by 720p sets and, conversely, 720p signals (ESPN, ABC, FOX) are handled very, very well by 1080i sets. Also, consider the fact that the Toshiba HD-A1, which is pulling down video from 1080p/24 and converting to 1080i/30 for display, and then often being pumped into a natively 720p or 768p display, is supposedly offering the best consumer-level HD quality video available anywhere. There's no reason to expect things to be different for Blu-Ray.

This is good news- because it means that the 720p discs that you might author in the future will look outstanding on the vast array of 1080i and now 1080p displays on the market, and not just on 720p sets.

Jake - you're entitled to your opinion of course. IMO I think the majority of LCD and Plasma displays out there do not stand up. I recently found one I did like which to my eyes looked relatively smooth and artifact free: the Samsung LA40M61B, but to me most of the sets out there introduced a significant amount of post processing artifacts that were easy to see, whether from an HD box or upscaled standard def. I don't think you can say whether one point of view is "true" or not - it's an opinion.

BTW the reaon people buy them is because they are slim, elegant and big screen - quality of image is a comparative thing and they are the only game in town.

If you have the huge capacity of BR, I can't see much reason to use anything but MPEG-2. The newer codecs make lots of sense for putting HD on red-laser DVDs, but with BR and 35Mbps -- why worry use a MS (or Apple) product and go out onto the bleeding edge. That's the reason the films coming-out are MPEG-2. We know how to do it well.

As far as MPEG-4 being the "future Broadcast codec," there is zero movement to include it in the USA's ATCS standard. Every DTV unit in the ATSC world would have to be tossed and rebought. Not gonna happen in this decade!

Ditto for cable boxes. Only DBS finds it cheaper to go with new boxes -- which customers may be forced to buy -- than put up more satelites.

Steve, in a few years cable providers will have to replace most of their boxes anyway because of the digital mandate. That includes digital to analog boxes to work with consumers who haven't switched.
Once Conrgess approves subsidies, it will happen and h.264 will be the standard. Just MHO.
btw, at NAB it seemed all anybody talked about was mpeg4 avs.

I'm actually curious about Verizons FIOS offerings, since they are planning on running fiber optic directly to homes accross the nation.

We actually live in incredibly interesting times, and unlike the Chinese, I don't feel like it's a curse.

Jake - you're entitled to your opinion of course. IMO I think the majority of LCD and Plasma displays out there do not stand up. I recently found one I did like which to my eyes looked relatively smooth and artifact free: the Samsung LA40M61B, but to me most of the sets out there introduced a significant amount of post processing artifacts that were easy to see, whether from an HD box or upscaled standard def. I don't think you can say whether one point of view is "true" or not - it's an opinion.

John, I'm sorry, but I have to respectfully disagree with regard to 1080/720 cross conversion. I don't think this is a matter of opinion at all- there's a sound technical process that has been in place for 5+ years in order to allow pristine cross conversion between the two major HD input types, and all displays do it the same way. Cross conversion between 720 and 1080 sources in HD displays is a simple matter of rescaling. No deinterlacing is required to display 1080i on a 720p set. 720p displays are fixed pixel by nature, and they run at 60hz, which is the key- the 1080i source is simply rescaled, and the fields are displayed as if they were frames at 720p/60 (59.94 fps). There's no field interpolation and no introduction of new motion artifacting caused by this process..

In the case of 720p to 1080i conversion, the process is simple as well. It's just a re-scale, and then artificial fields (artificial because inter-field motion will not be present in the signal) are simply assigned to the material as it's piped through. Again, this is non-destructive, and produces excellent results.

I would agree with you that many plasma and LCD sets sell because of ergonomics rather than performance, and all HD displays have a tendency to "junk" up their picture with post processing effects such as edge enhancement, black compression, etc.- but there's no technical reason for these displays to offer noticeably better performance when displaying 720p sources vs. 1080i ones. As a matter of fact, many of the '720p' plasma and LCD sets actually run a native res of 1366x768 or even 1024x768, and have to rescale everything you watch on them, whether the signal is standard def, 720p, or 1080i.

No matter how you want to slice it, whether our content is authored at 720p, 1080i, or 1080p, you can't escape the fact that the majority of displays you view it on will be using some sort of post signal processing to make it happen, and we need to be comfortable with that.

You guys seem to know much more about Blu-Ray than I do, so I'm wondering if you can answer some questions for me...

Let's say I have a 1280x720 movie running at 59.94fps with a 5.1 audio mix. Can I encode to MPEG2 in this format and produce a Blu-Ray compliant stream? Will a new wave of MPEG2 encoders be required or will good old Procoder 2 do the job?

Would I need any kind of special audio encoding to do the job? I take it that old fashioned DD5.1 is not supported. What is the maximum bitrate I can use to encode these movies?

Right now, I understand that Ulead DVD Factory 5 can author rudimentary Blu-Ray disks. Are there any other authoring tools aside from Scenarist BD that can do the job?

As far as using mpeg4 instead of 2...
I can think of one thing, cost savings....
When they want to sell box sets, or 2 or 3 movies as a packaging special...then mpeg4 could be an option just to fit everything on a single disk.
I've actually bought a few of those cheesy z grade horror movie packs with 10 DVDs in them, be nice to cut it down to 1 or 2.

Then with the advancment of IP/TV vc-1 and h.264 seem to be the leading candidates.

But who really knows how the market will shake out. Not me

Let's say I have a 1280x720 movie running at 59.94fps with a 5.1 audio mix. Can I encode to MPEG2 in this format and produce a Blu-Ray compliant stream?

Absolutely- as a matter of fact, the initial theatrical releases in BR format will all be MPEG-2 with 5.1 audio.

Would I need any kind of special audio encoding to do the job? I take it that old fashioned DD5.1 is not supported. What is the maximum bitrate I can use to encode these movies?

DD 5.1 is, indeed supported- that's no problem. The maximum total bitrate for BR is 36 mbps, which should allow for 2 hours of high quality MPEG-2 on a single layer BR disc, or 4 hours worth if you use VC-1 or AVC.

Right now, I understand that Ulead DVD Factory 5 can author rudimentary Blu-Ray disks. Are there any other authoring tools aside from Scenarist BD that can do the job?

None that I know of at this very moment, but there should be a wealth of options by year's end- everything from Nero to DVD Studio should be offering BR/HD-DVD authoring support.

Thanks for the response. I'd certainly be interested in seeing what the old Spruce/current DVD Studio guys come up with in terms of Blu-Ray support. I think it has HD-DVD support right now.

If they supported Blu-Ray I might even buy a Mac *gasp*

I have heard a dirty rumour that the consumer-level tools will be limited to MPEG2 though. Even at 32mbps, I'm seeing some artefacting at 720p/60 (!)

I heard similar info from the Pioneer guy (consumer authoring only being MPG2). He also said he has heard that those HD-DVD people trying to author with VC1 & mpg4 (currently trying to make Hollywood releases etc) are experiencing a significant number of problems using these codecs vs MPG2. This could be caused by Senarist though.

36Mbps = 16.2GB per hour
25GB per layer = about 1.5 hours per BR using its max data rate, rather than 2hours.

Fortunately we shouldn't need 36Mbps. Even just re-coding 720p HDV to the correct GOP structure for BR and maintaining its approximate 20Mbps gives 9GB per hour or around 2.7 hours.

PS: This Pioneer guy also said they have no plans to support MACs with with next gen drive, but he was talking from a Pioneer Australia perspective. I wouldn't doubt Apple will licence a model as an Apple SuperDupa Drive...

Hmmmm... I'm in regular contact with Microsoft and their work with VC-1 is extraordinary - and has been for many months. Their 15mbps encodes of notoriously difficult Xbox 360 720p/60 footage are practically flawless. Game footage has an infinite depth of field and hard, defined edges - extremely hard to compress compared to 'normal' HD material. Certainly, I'm finding it extremely tough for MPEG2 to get close right now, even with double the bandwidth.

As all HD-DVD titles on the shelves now are VC-1, I'd imagine the problems have been solved by and large and I'm fairly certain that it will be the future of encoding. Compression algorhythms have come a long way since MPEG2.

With regards the MPEG2 GOP structure, if they are using shorter GOPs on Blu-Ray, presumably this introduces more reference I-Frames. This will obviously result in a better picture quality but surely it will drink up the bandwidth?

It would also mean that our current HD encoding tools are useless for Blu-Ray which is a bit of a pisser considering that people already have 'homebrew' 1080i MPEG2 program streams working a treat on HD-DVD.

Is there any other source for this shorter GOP story?

No deinterlacing is required to display 1080i on a 720p set. 720p displays are fixed pixel by nature, and they run at 60hz, which is the key- the 1080i source is simply rescaled, and the fields are displayed as if they were frames at 720p/60 (59.94 fps). There's no field interpolation and no introduction of new motion artifacting caused by this process..



Hi Jake. Can you please explain how this works, because something doesn't seem quite right to me. I thought that, even when there is no rescaling involved, if you show interlaced video on a progressive panel without deinterlacing it, you would get interlacing artifacts. For example, if I show an interlaced DV AVI file on a PC's LCD monitor, I can easily see edge tearing on moving objects because each pair of fields is simply combined into frames. How do the 720p panels manage to avoid this without deinterlacing the 1080i video?

Richard

36Mbps = 16.2GB per hour
25GB per layer = about 1.5 hours per BR using its max data rate, rather than 2hours.



Hmm - if your original calculations are right 16.2 goes into 50 3x by my calculations. I'm sure I read somewhere that Sony have already demo'd a 100G BluRay disk with a promise of bigger capacities to come.

I also only made it 15.82 actual gigabytes an hour, but I'm guessing that 25GB per layer are maybe metric GB hence your figure?

Hi Jake. Can you please explain how this works, because something doesn't seem quite right to me. I thought that, even when there is no rescaling involved, if you show interlaced video on a progressive panel without deinterlacing it, you would get interlacing artifacts. For example, if I show an interlaced DV AVI file on a PC's LCD monitor, I can easily see edge tearing on moving objects because each pair of fields is simply combined into frames. How do the 720p panels manage to avoid this without deinterlacing the 1080i video?

Richard

Richard, Jake is sort of correct. The point I took from his previous post was that given a 1080i60 source you can make a 540P60 source (because you have enough lines vertically ie 540 lines every field) then you can upscale it to 720P quite effectively. I'm not sure if this still holds up when we're talking about 48i OR 50i embedded inthe 60 stream - I don't think most sets can display true 48Hz or 50hz (although some can display 100Hz) so his argument seems sound.

My point always was that *any* kind of scaling introduces artifacts, but certainly scaling from 1080i to 720P is nowhere near as bad as scaling from 540i or 576i. But consider this - if a scaler in an HD set does a poor job of scaling SD pictures, why would it be any better when scaling HD pictures (it's actually more data to manipulate)?

I always assumed that what was happening at the cheaper end of the scaling market in panels was that the set was re-compressing the image (re-encoding the MPEG stream to a data rate it could handle before scaling and re-encoding it to the panels native size). This was because on a lot of images I could see seemed to show excessive MPEG artifacting. However Jake seems to be much more knowlegeable in this area than me, so I guess I am seeing the results of excessive post processing.

Bottom line - nothing looks as good to me as my projector run from a DVDO iScan. (although I'm sure there are even better scalers than that if you want to spend the money) I watch HD off air and bypass (passthru) the scaler for that (it doesn't handle 1080i) and the projector seems to do an OK job with 1080i - but no better than standard def DVD scaled.

Hmm - if your original calculations are right 16.2 goes into 50 3x by my calculations. I'm sure I read somewhere that Sony have already demo'd a 100G BluRay disk with a promise of bigger capacities to come.

I also only made it 15.82 actual gigabytes an hour, but I'm guessing that 25GB per layer are maybe metric GB hence your figure?

Given I worked out 16.2 = 1.5Hr per layer it makes sense a two layer 50GB disk would support 3 hours does it not?

36Mbps /8 = 4.5MBps = 270MB/minute = 16,200 MB per hour.
=16.2GB per hour using 1000MB per GB or
= 15.82GB oer hour using 1024MB per GB

The relevant question is if the 25GB is 25 x 1000MB or 25x 1024MB (probably neither if we consider below)?

DVDs are stated as 4.7GB but I believe that is using 1000MB=1GB resulting in a little under 4.5GB usable using 1024MB=1GB etc

PS: Most HDD manufactures quantify their drives using 1GB = 1 Billion bytes, not 1024 MB and I think DVD, BR and HD-DVD will do the same.

What looks like excessive artifacting on a Plasma is in fact the pulse width modulation that it uses to generate all it's greyscale levels (really the plasma pixel is binary - on or off, so it needs to be modulated to produce different visible levels) interfering with movement in the image and the human visual system.

And you're right, 1080i60 should convert to 720p60 by splitting each field into a 540p60 frame, then upscaling to 720p. Given all modern displays are inherently progressive, 720p is displayed on a 1080p screen by simple upscaling.

Graeme

Given I worked out 16.2 = 1.5Hr per layer it makes sense a two layer 50GB disk would support 3 hours does it not?

36Mbps /8 = 4.5MBps = 270MB/minute = 16,200 MB per hour.
=16.2GB per hour using 1000MB per GB or
= 15.82GB oer hour using 1024MB per GB

The relevant question is if the 25GB is 25 x 1000MB or 25x 1024MB (probably neither if we consider below)?

DVDs are stated as 4.7GB but I believe that is using 1000MB=1GB resulting in a little under 4.5GB usable using 1024MB=1GB etc

PS: Most HDD manufactures quantify their drives using 1GB = 1 Billion bytes, not 1024 MB and I think DVD, BR and HD-DVD will do the same.

Sorry Guy - I misread your intent - I thought you were saying you couldn't fit a 2 hour movie on a BluRay disc at it's maximum data rate. I have since discovered that all the current BD movies are single layer? very strange decision.

The relevant question is if the 25GB is 25 x 1000MB or 25x 1024MB (probably neither if we consider below)?

Most computer media capacities are now expressed in decimal rather than binary amounts, and that's officially recognized as the modern standard. (Binary calculations are supposed to be expressed using a new set of terms approved in 1998: see http://en.wikipedia.org/wiki/Mebibyte.) A better question is what's the formatted capacity, and how full can you fill it before playback at the outer edge gets iffy? So let's say a single-layer Blu-ray disc holds ~24,000,000,000 bytes comfortably * 8 bits per byte = ~92 minutes at 36 Mbps or 128 minutes at 25 Mbps or 185 minutes at 18 Mbps. That sounds like plenty to me, and I'd rather not have to fuss with multi-layer discs.

...I'd rather not have to fuss with multi-layer discs.

Same here. While I have burnt a few DL DVD-Rs and they have worked, for a while anyway*, I have never used them to provide a finished video to a client.

*As feared even with Verbatim DL disks it doesn't take long for the same disk in the same player to start having playback problems. Its like after burning, the reflectivity steadily degrades for a while reducing compatibility with time. DL BR will need so time to convince me its a safe delivery format.

I was of course referring to multi-layer replicated commercial disks (movies) and not burnt disks. I thought Sony had already been using dual layer BD-R on XDCam? Maybe not.