Ask questions to BD authoring and compression insider "2themax"

[2themax]

Originally Posted by 4K2K

Why wasn't 1080i included too since it will be what 3D TV will sometimes be shot in? Surely it would be better to keep everything in their original format instead of forcing format conversions to lower spatial or temporal resolutions which including only these options will mean will have to be done for 1080i 50 / 60 content.

I don't know why, but I can think of a few reasons. Possibly keeping the interlace from the left and right eyes in phase could be part of it or the extra bandwidth needed for 1080i. Again, these are just guesses.

[2themax]

Originally Posted by JamesN

That would mean that 3D BDs would not be backwardly compatible with existing 2D BD players (without a firmware upgrade). This was not my understanding. In fact, one of the selling points of the new 3D technology has been that content providers would be able to produce a single BD of a given title that would play in either legacy 2D players (in 2D) or in newer 3D players.

I've always wondered how this would work, and like you I am dying to hear what the internal storage layout of such a disc would be to be able to accomplish that.

Think of it as seamless branching when the player is reading the 2D only stream. The player is basically branching over the 3D portions as it is playing. In 3D mode, it would alternate between reading 2D and 3D streams on the disc.

[2themax]

Originally Posted by Jeff Kleist

The encoders are taking in 2 streams from what I understand.

That's correct.

[Penton-Man]

Originally Posted by 2themax

They are working on it and Panasonic is leading the way. Sony will have a demo of Blu-print at NAB, but I doubt it ready for mass production.

Hi 2themax!
Good to see some folks here kick-starting your thread and taking advantage of your presence.

Yes, there will be a demo of Blu-print(3D) at NAB and in fact, Beta-versions are already being used by several outfits (outside of Sony Pictures) which have interest in it.

[Talkstr8t]

Originally Posted by 4K2K

Why wasn't 1080i included too since it will be what 3D TV will sometimes be shot in?

1080i is more demanding to decode in 3D, which meant some platforms would have difficulty supporting it. For sports content most feel 720p would be suitable (since arguably 720p is a better format for sports than 1080i), and movies generally aren't shot in 1080i.

- Talk

[2themax]

Originally Posted by Penton-Man

Hi 2themax!
Good to see some folks here kick-starting your thread and taking advantage of your presence.

Thanks Penton

Yes, there will be a demo of Blu-print(3D) at NAB and in fact, Beta-versions are already being used by several outfits (outside of Sony Pictures) which have interest in it.

Add me to the list of people with interest in it, but we happen to use a certain competitor's software...for now.

[JamesN]

Originally Posted by 2themax

Think of it as seamless branching when the player is reading the 2D only stream. The player is basically branching over the 3D portions as it is playing. In 3D mode, it would alternate between reading 2D and 3D streams on the disc.

Thanks for all your replies, but I'm still more than a little confused. Your above reply implies the left/right images are encoded as discrete streams. Yet in a different post, you stated:

Blu-ray 3D encoding is done as frame packed. Each frame is 1920x2205.

I am aware of what frame packing is, but I thought it was related to the output format of the 3D signal, and not necessarily to how the data is physically stored on the disc. I still can't get my head around how a legacy 2D Blu-ray player could read and understand a video stream with a 1920x2205 resolution.

Unless you mean that the player could somehow be instructed to branch on every other frame? Surely that would be terribly inefficient?

[DaViD Boulet]

Originally Posted by JamesN

Thanks for all your replies, but I'm still more than a little confused. Your above reply implies the left/right images are encoded as discrete streams. Yet in a different post, you stated:

good question. Since the 3D component/second eye angle "piggy backs" on the core 2D stream, I'm also curious if it's all bundled in the same AVC encode stream or if it's two separate streams. I'll wonder if it works similarly to DTS-HD MA with the "core" DTS stream.

I am aware of what frame packing is, but I thought it was related to the output format of the 3D signal, and not necessarily to how the data is physically stored on the disc. I still can't get my head around how a legacy 2D Blu-ray player could read and understand a video stream with a 1920x2205 resolution.

Unless you mean that the player could somehow be instructed to branch on every other frame? Surely that would be terribly inefficient?

I think he said "branch" when he really meant "alternate angle"... different branches are physically read by moving the laser to a different location on the disc... that wouldn't work for 3D. But different angles are all gathered from the same laser "read" and share a common bandwidth pipe accordingly. I think this is the jargon/illustration he meant to use.

[kjack]

Review how MPEG-2 transport streams and the corresponding tables work...

An example I like to use is when a broadcaster adds a second program to a HD broadcast. Unless the receiving devices are told about the new second program and they can support it, they ignore it; don't even know it exists.

[JamesN]

Originally Posted by kjack

Review how MPEG-2 transport streams and the corresponding tables work...

An example I like to use is when a broadcaster adds a second program to a HD broadcast. Unless the receiving devices are told about the new second program and they can support it, they ignore it; don't even know it exists.

So help out a poor, dumb layman here...

A transport stream can actually be stored on a BD disc, as opposed to a program stream? Or is the TS disguised as a PS on the disc and only recognized as such by 3DBD players?

Edit: After further research I see that Blu-ray does indeed work with TS. I also see that HD-DVD worked with PS. Does that mean that (at least for this particular implementation) 3D would not have been possible on HD-DVD?

[2themax]

Originally Posted by JamesN

I am aware of what frame packing is, but I thought it was related to the output format of the 3D signal, and not necessarily to how the data is physically stored on the disc. I still can't get my head around how a legacy 2D Blu-ray player could read and understand a video stream with a 1920x2205 resolution.

Unless you mean that the player could somehow be instructed to branch on every other frame? Surely that would be terribly inefficient?

That was a poor choice of words on my part. I should have said Blu-ray 3D is transmitted as frame packed. Each frame is 1920x2205. Encoding is still done as 1920x1080 per stream.

[2themax]

Originally Posted by DaViD Boulet

I think he said "branch" when he really meant "alternate angle"... different branches are physically read by moving the laser to a different location on the disc... that wouldn't work for 3D. But different angles are all gathered from the same laser "read" and share a common bandwidth pipe accordingly. I think this is the jargon/illustration he meant to use.

That's a good analogy for 3D playback especially with the interleaved files on the disc. I was thinking in a 2D world when I was answering.

As a side note, I finally got the final printed Blu-ray 3D spec today. No more reading draft copies!

[kjack]

At C3D World today, there was a nice presentation by Panasonic about how 3D BD is implemented, and included a great diagram showing how things work in 2D vs. 3D mode...

In short, a 3D bitstream on the disc contains interleaved base and enhancement TS packets. A 3D player reads and processes both TS packets. A 2D player reads and processes only the base TS packets, automatically skipping over the enhancement TS packets.

[JamesN]

Originally Posted by kjack

At C3D World today, there was a nice presentation by Panasonic about how 3D BD is implemented, and included a great diagram showing how things work in 2D vs. 3D mode...

In short, a 3D bitstream on the disc contains interleaved base and enhancement TS packets. A 3D player reads and processes both TS packets. A 2D player reads and processes only the base TS packets, automatically skipping over the enhancement TS packets.

Thank you!

Another question if you don't mind: Can the encoder take advantage of the fact that the left/right frames of a 3D image are highly redundant in nature and exploit that fact in the compression stage, even though those frames will ultimately become part of separate TS packets? I guess that would depend on whether packets are implemented virtually or physically?

[Jeff Kleist]

Another question if you don't mind: Can the encoder take advantage of the fact that the left/right frames of a 3D image are highly redundant in nature and exploit that fact in the compression stage, even though those frames will ultimately become part of separate TS packets? I guess that would depend on whether packets are implemented virtually or physically?
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That's the entire way it works, and how it achieves only a 50% increase in bandwidth.

[DaViD Boulet]

Originally Posted by Jeff Kleist

That's the entire way it works, and how it achieves only a 50% increase in bandwidth.

Yep. It's one of the great things about AVC, and it provided a much more efficient solution that utilizing the 2nd alternate video stream in 1080p for the second eye angle which would have also provided backwards compatibility with 2D players, but at the cost of having 2 fully independently compressed streams (which would have doubled bandwidth/space needs for video).

AVC's solution is awesome with left-right eye differential, and I was pleasantly surprised to find out that the BDA had figured out a way to author 3D blu-ray discs using this method that still preserved backwards compatiblity witih legacy gear. I think that the 3D solution on blu-ray is one of the more rare examples of something being done impressively "right".

[dlancelot79]

Hi 2themax,
I did a search on this forum and I can't find any post that discusses Sequence Key Block (SKB). I also searched the web to see if there're any titles that uses the SKB protection, but I got 0 results.

Questions:
1. Have you come across any BD titles that uses SKB?
2. Why isn't SKB being widely used on BD?

Hope you would be able to advice or point me in the right direction. Thanks. =)

[F-Man]

Anyone know who to contact at Sony about a movie that may have had a slightly wrong aspect ratio on DVD, and telling them to make sure to look into it for the future Blu-ray release?

EDIT: solved.

[PeterTHX]

Originally Posted by F-Man

Anyone know who to contact at Sony about a movie that may have had a slightly wrong aspect ratio on DVD, and telling them to make sure to look into it for the future Blu-ray release?

Which film?

Some of their movies lately have been showing less information than the DVD version (zoomed in), such as Crouching Tiger, Hidden Dragon.

In any case, try Penton's thread (SONY insider):
https://forum.blu-ray.com/insider-di...enton-man.html

[JamesN]

Originally Posted by kjack

...In short, a 3D bitstream on the disc contains interleaved base and enhancement TS packets. A 3D player reads and processes both TS packets. A 2D player reads and processes only the base TS packets, automatically skipping over the enhancement TS packets.

Do the menu assets on a 3D BD follow the same methodology? That is, are buttons, widgets, motion menu video, etc. stored as separate streams on the disc?