You cannot count on 54 Mbit/sec sustained. You can only count on 36 Mbit/sec sustained, edge to edge.
|Regarding video codecs: Blu-ray WILL include at least one advanced video codec beyond MPEG-2. Current candidates include MPEG-4 AVC High profile and VC-9. Rest assured that Blu-ray will simply be able to hold more HD video than any other optical disc format.
I don't think we've had any crystal clear comparisons as to the advantage of each Codec. Microsofts apparently made some tradeoffs to gain further efficiency and decreased encoding time. Amir mentioned some differences in the past, but I'm still amiss on the differences. This would be a nice areea to clear up further. If HD-DVD can provide H.264 and VC-9, why not provide both for Blu Ray as well?
|I can't tell you all that we learned, but I can tell you that 8Mb/s looks pretty good, and that there are measurable, subjective improvements by moving to 12Mb/s and 15Mb/s for certain advanced codecs.
Let me be the first to say I sincerely hope that 15 mbit/sec *minimum* is used, should that be the case. Further, assuming we have 50 Gig for hollywood prerecorded movies, I'd like to again emphasize the bottom line. How much room is left after encoding the movie (assuming 2 and 3 hour movies) and adding the various audio tracks, including at least one primary lossless compressed track of 24/48 minimum?
4 layers of Blu Ray = 100 gig. Is 8 layers also achieveable? Are layer changes going to be an issue? (I still have pauses with my DVD player, and the audio relay on my Meridian 861 clicks on and off at the layer change).
Sorry if this is repetitive, but I just wanted to repost this:
That is one of the major strengths of Blu Ray. I have to say the argument about uneccessary storage space doesn't hold water (unless it is squandered). I'd be perfectly happy with multichannel 24/48 lossless compression for pre-recorded hollywood movies, however, I'd be the first one to be thrilled with 24/96 in all discrete channels, including 2 height channels, perhaps an over head ceiling channel, rear center, and discrete sides. If you participate on the surround sound forum (which include the head recording engineers from Telarc, Chesky Records, and many others accross the world) you'll see the desire for more discrete channels, PERIOD. If our goal is to make movies more involving (virtual reality) then we need to address what would bring us closer to those goals. That means more accurate 3 dimensional sound, accurate touch/tactile, motion, etc... Fortunately tactile is very affordable and easy to implement. Further (as a neuroscience person and M.D. who has done lots of literature searching to compile a review article on this subject) the human tactile system only functions from 0+ to approximately 600 Hz maximum... so it would only take negligible bandwidth/storage to add limited bandwidth channel(s) for this purpose. Of course I wrote more in my sig file below regarding the need for a discrete tactile transducer channel. A discrete tactile transducer channel would take Blu Ray/HD-DVD to a new level and wouldn't take anything other than the sound engineer to mix an appropriate discrete track using the correct information, frequencies, and levels.
Of course, proprietary discrete 3-D motion and tactile has been utilized by D-BOX Oddessey. I had the opportunity to demo one at Overature in Delaware a little while back, but that's another story which I'm too tired to discuss as I just got home from 26 hours of work...
I think the biggest hold up on development of more advanced surround formats is simply the economics of commercial theaters: they are just not doing well to say the least. Considering that the home market now makes for 50% of the revenue for movies, I hope that consumers quit underestimating their power and start demanding more from these entertainment companies. These are entertainment companies, not commodities. There is ample proof of consumer power if yo go bak and read the comment from the Lions Gate CEO that was quoted earlier in this thread.
The reason I equate Sony with Blu Ray is because Sony is the leader with the major studio. When Sony talks about what their vision of movies will be like on Blu Ray, that is what matters. Ultimately you think a studio should be able to provide whatever feature they like, but what about the limitations provided by the Blu Ray format? The fear is that whatever is designed NOW, will likely have limitations that might not allow for easy add-on features later. Look at what a nightmare DTS caused with DVD. Once you create a format, it is hard to make any significant change for years. So my concern is primarily over what can and can't be done with Blu-Ray. I think having a choice of 3 codecs is outstanding. I'm hoping for more out of Blu Ray than just 1080p and 5.1/6.1 lossless compressed audio.
You want to know why some of us still have issues with Sony, it is likely because the 50 Gig *was* going to be used for 1080i/p MPEG-2 only and standard DD/DTS... If that was the case, you'd better believe HD-DVD with VC-9/H.264 and lossless audio compression is more appealing! That is why I/We are waiting to hear more concrete facts about 1080p, 24/48, 24/96 lossless audio, VC-9/H.264, etc... Not to mention HD-DVD is talking about letting consumers make limited back-up copies. We need to hear more about what can and can't be done with BLU RAY. We need to hear more on what audio can/will be provided. We need to hear more about new features. Take the guess work away and take this new format to the highest possible level. Once Blu Ray makes these issues more clear, I'm sure there will be loss of hesitation to fully back Blu Ray.
I'm certainly not pro Blu Ray or Pro HD-DVD, I'm pro bottom line! But again, if all things are equal, the bottom line is best served by 50 gig vs 30, if the bottom line is maximally fullfilled. Filling up 200+ Gig is easy, if you don't think so, then your absolutely crazy: 4:4:4:4 10 bit please...