Seamless Branching

[darinp2]

I would like to get some feedback from both sides on seamless branching. Basically, more exact figures for the limitations of each format right before a branch could be taken or not. From what I've read the main track needs to be limited to an average of around 60% (or low 60s) of the peak mux rate for a short period right before the branch point. Hopefully somebody can correct that if it is wrong and provide exact numbers. My understanding is this is so that there will be enough data stored up to continue playing the video while the laser goes to the alternative track, if that track is to be played. Each alternative track would then have 2 branch points. I picture this like a train going down the tracks with a slower speed limit right before a point where the track splits and that speed limit needs to be observed whether taking the alternative track or not. And if the alternative track is taken, then the train needs to come back to the main track later.

An example of where branching can be useful are discs with regular cuts and alternative (like Director's or unrated) cuts where the user can choose which to watch. I believe that "AVP: Alien vs Predator" has been announced to have seamless branching for Blu-ray with 2 cuts. MI:3 for HD DVD has branching, but that shouldn't be confused for seamless branching from what I saw. One spot early had about a 1 second pause going to the alternative track and about a 5 second pause (although some of it might have been in the source) coming back to the main track. Another case where seamless branching can be useful is in changing things like a note or billboard that is shown so that it is in the language of the currently selected language track. With CGI getting better and better, this should be more possible in the future. I recall reading about "True Lies" needing modification to a name of a company on hats and things before it could be released because it was too close to a real company name, so I know they can modify things like that (although that wouldn't have been an example of seamless branching).

Some things we know are that HD DVD has a total mux rate of about 30Mbps for all audio and video (and 36Mbps off the discs) that comes from their choice to spin the discs at 1.0x, while Blu-ray is at 48Mbps total (and 54Mbps off the discs) that comes from their choice to spin the discs at 1.5x, while they have a max video rate of 40Mbps.

I am especially curious how the HD DVD side plans to handle seamless branch cases for average to hard scenes without degradation given their lower limits. Right now we have releases without seamless branching where things other than the main video take up about 11Mbps, leaving about 19Mbps peak for video. I'm pretty sure there are releases where the average (not the peak) for video is higher than 19Mbps. We have also been told that Microsoft has a plan to do dynamic muxing to deal with the 30Mbps ceiling, and that was before seamless branching was even discussed, from what I recall.

If we give them some benefit of the doubt and figure 8Mbps for things other than the main video, that would leave 22Mbps peak for video. Add seamless branching with those 8Mbps still being used and now with the total for everything right before a branch of somewhere around 19Mbps, that would leave 11Mbps for the main video. That would probably work if the video is easy there, but have more difficult video there and that is a whole lot more limiting than the 19Mbps peaks that we are seeing on some titles currently that still take weeks to get encode to the states we get them in. For the above I didn't even really include going to the 20/48 or 24/48 TrueHD that has been discussed, instead of the 16/48 TrueHD currently.

One more thing is that the average right before a branch point shouldn't be confused with averages we see for whole movies. Difficult frames tend to have a correlation to difficult frames around them. Just because a 2 hour movie can average 12Mbps and look good, that doesn't mean every 2 second segment of that movie could look good with 12Mbps.

So, I am curious. What is the plan for seamless branching support given the above issues and how will the more difficult cases be handled? Will the HD DVD team consider spinning the discs at 1.5x when/if they go to 45GB discs so that seamless branch points aren't nearly as limiting as they are with their 1.0x spin rate?

I already know that some won't want us talking about more difficult cases than we've seen or that I might get answers that include BD50s being science fiction, Blu-ray being MPEG-2 while HD DVD is VC-1, or that we shouldn't look at upcoming issues unless current discs compare in a certain way, but those are all to be expected at this point.

--Darin

[WayneL]

Darin, with all respect, and not wanting to short-circuit any answers to your questions, I for one would not be dismayed if either format decided to put out two unbranching versions of a title out on one or two disks.
My holy grail would be to personally & non-sequentially flag to produce my own cut (there would be a lot more single story lines & dropped personal non-sequitors than editors/directors do). I could even see the studios doing this to provide "Clean" options if they thought it would sell. But I don't think they will support any of these.
So, when you mean seamless, do you mean an invisible track change and re-synch on a "random" basis? If HD can't do it, is BD going to do this on a meaningful level even if they can?
Having said that, I wait too for the answers to your query.

[darinp2]

Originally Posted by WayneL

So, when you mean seamless, do you mean an invisible track change and re-synch on a "random" basis?

Random would be really tough. I was talking about cases where the people encoding know where the alternative tracks are. An example might be a scene in one of the Lord of the Ring movies where the extended cut shows some more hits in a battle and if the user selects the extended cut the scene looks to them like it would if the other cut wasn't even on the disc (no pause) and vis versa if they watch the regular cut. I could also see them using something like this for "clean" or "family friendly" versions, although I don't know if we'll see that either. Definitely scenes where there is extra nudity over what was shown in the theaters would be an example of where they could include both versions with seamless branching.

I think they would want to be careful about including two discs of the same movie with different versions, because many people would just sell the version they don't want. Flippers with a version on each side would be one option, but I don't think that is as nice as single sided discs and I think many agree.

BD would be limited also, just as HD DVD would be even if they did up their disc spin rate to 1.5x. But not as limited as with 1.0x spin rate.

--Darin

[BuGsArEtAsTy]

Personally I think seamless branching is mostly irrelevant to most people, myself included.

think they would want to be careful about including two discs of the same movie with different versions, because many people would just sell the version they don't want.

They used to say the same thing about DVD, but just about nobody sells one of the two discs alone from a "deluxe" DVD. This is a non-issue.

[darinp2]

Originally Posted by BuGsArEtAsTy

They used to say the same thing about DVD, but just about nobody sells one of the two discs alone from a "deluxe" DVD. This is a non-issue.

Are you talking about DVD releases where there are two discs and each disc contains a full version of the movie, or releases where there are extras on a second disc? They are very different things.

And it doesn't matter whether a person will watch the main version or the alternative version if seamless branching is used and the video is degraded at points to handle the branching.

--Darin

[hmurchison]

I think the truth is evident.

Both formats are hobbled by yet another generation of slow and crappy optical technology. Can't we just bypass the problems by storing the HD content on HDD storage and increasing the bandwidth the asics can handle?

[WiFi-Spy]

Does someone have a link to a white paper on seamless branching? (Reg. DVD)

[price3]

I don't think seamless branching will be used any more frequently in this generation than it was last time, there just isn't much call for it and it cuts off the additional double dip revenue stream.

[BuGsArEtAsTy]

Originally Posted by darinp2

Are you talking about DVD releases where there are two discs and each disc contains a full version of the movie, or releases where there are extras on a second disc? They are very different things.

I am talking about DVD releases where there is more than 1 disc, with versions of the movie on separate discs. Brazil comes to mind.

Nobody breaks these box sets apart for sale. It is a complete non-issue.

The only time I've ever seen box sets broken apart for sale is when the different discs contain completely different movies or different episodes of TV shows.

Originally Posted by price3

I don't think seamless branching will be used any more frequently in this generation than it was last time, there just isn't much call for it and it cuts off the additional double dip revenue stream.

Yup. Seamless branching is mostly just a gimmick that consumers don't care about.

[darinp2]

Originally Posted by BuGsArEtAsTy

I am talking about DVD releases where there is more than 1 disc, with versions of the movie on separate discs. Brazil comes to mind.

Nobody breaks these box sets apart for sale. It is a complete non-issue.

I wasn't talking about stores. I was talking about some individuals who will either sell or give away discs they won't use. I don't know about special things like Criterian collections, but studios are concerned about providing people separate discs of a movie where they can pass on the one they won't use. Do you understand why studios prefer combo discs with HD DVD to including an HD DVD and a DVD of the movie separately in the package?

Originally Posted by BuGsArEtAsTy

Yup. Seamless branching is mostly just a gimmick that consumers don't care about.

Most consumers won't even know when seamless branching is used. But studios like to put multiple copies of a movie on one disc for multiple reasons. One, so that they don't have to have separate releases for things like a rated cut and an unrated cut. It probably also helps sell it to some consumers as they see that they can choose the version they want to play at any time and aren't locked into one version at purchase. For instance, so they could play the rated version for certain people (like with younger people or their parents ). But they don't have to know whether the versions were included completely separately or whether they were put on with seamless branching. From what I've seen, unrated and Director's cuts have become more common with time.

Why do you think "AVP: Alien vs Predator" will have two versions on one disc?

--Darin

[Art Sonneborn]

Darin,
Have you heard that studios actually see a market for this feature ?

Art

[BuGsArEtAsTy]

Originally Posted by darinp2

I wasn't talking about stores. I was talking about some individuals who will either sell or give away discs they won't use. I don't know about special things like Criterian collections, but studios are concerned about providing people separate discs of a movie where they can pass on the one they won't use. Do you understand why studios prefer combo discs with HD DVD to including an HD DVD and a DVD of the movie separately in the package?

I have NEVER seen a broken up disc set on eBay. I suppose if I looked hard enough I could find rare instances of this, but again, this is a complete non-issue.

[xradman]

I, as a parent of young children, would love to see, and pay extra for seamless branching of certain movies so that they contain both an R-rated and PG-rated (or TV version if already available) on the same disc. I think this was possible even with DVD, but sadly people like myself must have been in the minority. There are many movies that I would love to watch with my wife and kids, but due to certain short scenes that they find objectionable, I cannot.

[WayneL]

Originally Posted by xradman

I, as a parent of young children, would love to see, and pay extra for seamless branching of certain movies so that they contain both an R-rated and PG-rated (or TV version if already available) on the same disc. I think this was possible even with DVD, but sadly people like myself must have been in the minority. There are many movies that I would love to watch with my wife and kids, but due to certain short scenes that they find objectionable, I cannot.

This is why I think seamless branching is unimportant. The studios are too lazy, proud or rich to do this now. By doing it they would expand the buyer base of every PG movie. Alternate cuts are of interest to a very few fans - 2 disk sets would work fine.

[evader45]

I think that most directors and perhaps some studios are opposed to sanitized versions of their movies. Several studios and the Directors Guild of America even won a lawsuit against a company named CleanFlicks that was producing edited versions of DVDs.

I also think that most "Directors Cut" DVD versions are versions that the director preferred but did not make it in the theatrical release due to either length or ratings (read NC-17) concerns. In almost all cases, I prefer the directors cut and would probably never watch or buy the original version.

Say that there were a PG-13 and an R rated version of the movie on the same disk, would there need to be some sort of parental control switch included? Would a minor be prohibited from buying such a disk? It seems easier to handle with 2 disks.

The studios may see some advantages to seamless branching, but I have yet to see any advantages that would interest me personally.

[Kosty]

I see it as a niche item that will have very little practial impact. For most releases the deleted scenes or directors cut standalone version is sufficient.

Most movies don't have the interest to have this done, for a catalog title there no money to do it, and for most movies the directors have already walked away, its tough enough for them to record an audio track for the commentary.

I think seamless branching has its most potential to "G rating" neuter a movies naughty parts, but I think the cost of doing that from the studio side is noo much and artists would object so its a can of woems for the studios.

[WayneL]

Originally Posted by evader45

I think that most directors and perhaps some studios are opposed to sanitized versions of their movies. Several studios and the Directors Guild of America even won a lawsuit against a company named CleanFlicks that was producing edited versions of DVDs.

They made a big noise about artistic rights, but I think it boiled down that somebody else was making money doing the edits, when that right was exclusively theirs. IMO

[xradman]

Originally Posted by Kosty

I see it as a niche item that will have very little practial impact. For most releases the deleted scenes or directors cut standalone version is sufficient.

Most movies don't have the interest to have this done, for a catalog title there no money to do it, and for most movies the directors have already walked away, its tough enough for them to record an audio track for the commentary.

I think seamless branching has its most potential to "G rating" neuter a movies naughty parts, but I think the cost of doing that from the studio side is noo much and artists would object so its a can of woems for the studios.

For most movies that have been or will be shown on broadcast TV, sanitized versions are available or will soon be available. I really don't see why this can't be done for very little cost during mastering. I remember HK DVD version of Shaolin Soccer had seamless branching for both extended and normal version of the movie, and it worked relatively well.

[darinp2]

Originally Posted by Art Sonneborn

Have you heard that studios actually see a market for this feature?

I have heard of interest in it. But even besides that we can look at the fact that "AVP: Alien vs Predator" has been announced to use it on Blu-ray, Paramount used branching on MI:3 (although not seamless from what I could see), and there are DVDs with seamless branching.

Here is a DVD set for "The Lord of the Rings" on Amazon:

http://www.amazon.com/Rings-Trilogy-...?ie=UTF8&s=dvd

that says:

Disc 1 will present the Special Extended DVD Edition of the film split into two parts (on two sides of a DVD-18) at the break point of the initial DVD release. The Theatrical version will also be split into two parts (on two sides of a DVD-18) available through seamless branching.
...
Disc 1: For the first time, the Theatrical and Extended versions of each film are on one disc! This 2-sided DVD puts both versions of the epic film on one convenient, portable disc. You can choose which version you'd like to see from the main DVD menu.

According to the specs, it looks like DTS 6.1 ES was on the original extended discs, but was dropped for the seamless version, which makes some sense given the limitations of branch points there.

I don't see seamless branching as something were there will be less of it with time, but more if anything.

Originally Posted by BuGsArEtAsTy

I have NEVER seen a broken up disc set on eBay. I suppose if I looked hard enough I could find rare instances of this, but again, this is a complete non-issue.

So, do you believe that Amir's comments about studios wanting to use combo discs instead of including an HD DVD and a DVD because people could pass one on were false?

--Darin

[BenDover]

Originally Posted by darinp2

...

So, do you believe that Amir's comments about studios wanting to use combo discs instead of including an HD DVD and a DVD because people could pass one on were false?

--Darin

you're not trying to rationalize studio paranoia, are you?

[darinp2]

Originally Posted by BenDover

you're not trying to rationalize studio paranoia, are you?

Just trying to live in the real world. The studios will do what the studios will do, whether I like it or not. We can argue about what they should do, but that is different than discussing what they will do.

--Darin

[Forceflow]

Originally Posted by darinp2

According to the specs, it looks like DTS 6.1 ES was on the original extended discs, but was dropped for the seamless version, which makes some sense given the limitations of branch points there.

I don't see seamless branching as something were there will be less of it with time, but more if anything.

Darin,

I agree that seamless branching is being used in DVD but we must realize that it isn't critical to consumer purchases. If LOTR was available in DTS 6.1 ES as only the EE, and DD 5.1 as both TE and EE, I bet you 90% of the AVSForum would buy the DTS 6.1ES with only EE simply because it isn't as big of a deal as the loss in sound.

Seamless branching eats up bandwith at the juncture points (as you noted). This really creates havoc for the compressionist and the sound mixer should be aware of this as well. If TrueHD tracks, or even DD+ could vary in bitrate rate around the branch points, this may free up bandwith (create 1 second of silence preceding and after branch point). The loss of sound would not be as annoying as the loss of video or a stutter.

I'm sure innovation will allow seamless branching in HD DVD. As you said, later in the format's life is when it will be utilized most. We can afford to enjoy what we have right now and work on that issue when consumers start hankering for a double dip.

[BenDover]

what info from the bd side are you looking for exactly? ie, what info would be useful/helpful? keep in mind that the bd specs are 'confidential'...

[darinp2]

Originally Posted by BenDover

what info from the bd side are you looking for exactly? ie, what info would be useful/helpful? keep in mind that the bd specs are 'confidential'...

Basically, the bitrate limitations before the branch points. Like, is it ~60% of the normal rates as an average for the 2 seconds before the branch? And then whether there are any other relevant limitations related to these branch points.

--Darin

[WayneL]

Here's a guess - you will never know

[darinp2]

Originally Posted by WayneL

Here's a guess - you will never know

I think I'll be able to get the information. Might not be able to share it, but I think I'll get it at some point.

One thing that will be interesting is if somebody with a way to monitor the bitrate can do it for AVP, when that comes out. I just read that the G2 Toshiba player lists a bitrate monitor as a feature. I hope it is true as it could be very interesting if we can look at instantaneous bitrates.

--Darin

[jim_r]

Seamless branching? Add that to the list of features I could not care less about. Move over IME and U-Control.

[chefboy1]

I guess I'm one of the few that see a lot of potential for seamless branching.

After watching Memento on dvd back in 2002, I immediately thought it'd be a great idea if there was an option to view the movie again, however, each scene in chronological order. I think people would have a better appreciation of how well-made the film was.

As someone mentioned Shaolin Soccer earlier (and with many foreign comedies), the Hong Kong and english releases were very different. Some of the humour that is hilarious to an asian audience just doesn't translate very well over to english and would only serve to leave an english audience scratching their head and bogging down the flow of the movie with uncomfortable dead spots. Hopefully with seamless branching, a viewer can choose the chinese language version and see the original cut; alternatively, if a viewer chose the english dubbed version, they'd get the edited version that keeps the humour relevent to the audience and the pace steady.

However, as a parent, I'd say the best use of seamless branching would be the ability to choose between various versions: an unrated cut, the original theater cut and a family-friendly (ie. tv broadcast) version. Doesn't most players already have parental control features built in? Why bother implementing this if they didn't intend to use it??

To say seamless branching is unimportant or calling it a non-issue appears lacking in imagination and short-selling the consumer.

[hdkhang]

To me seamless branching means, there are two versions of the same scene, not that one version has bits cut out of it. Is this what we are talking about?

As to whether it is worthwhile, I guess I'm one of those that don't really feel it is, but not strongly objecting it.

Many are asking for it as a means of parental control... I agree that many great movies could be made child friendly if only it had one or two scenes cut out of it, oftentimes these scenes are not totally necessary to move the story along. However I appreciate that it is the way the movie was intended, I feel if parents are looking out for their children (and that is a good thing) then it is a noble request, but at the same time I feel the directors etc. felt the movie was not intended for that audience anyway. It's not cut and dry like that rollercoaster ride at the amusement park where they designed the ride so that persons under a certain height (cue the clown) are prohibited from riding, but it is something along those lines in that the director intended it for a specific audience. Imagine if I write a thesis about some uber technology, I wouldn't be handing it over to someone who opposes technology to read it and then have them tell me what I wrote is offensive etc. It's the same here, if you read the classification and it says not recommended for under 15s etc. and you allow a 5 year old to watch it, then you can't really expect to have any legs to stand on when you try to trash the movie from that viewpoint.

At the end of the day, the movie wasn't designed for your kids, just like some magazines aren't designed for your kids. If you feel there is adequate value in the content bar a few naughty bits, then it's probably best if you ask your kids to close their eyes for the next few seconds and be done with that. Important is that you explain to them that they can't watch this bit because they aren't old enough to understand.

I recall watching Dead Poets Society when I was 14, it was a movie which I felt was fantastic then and now. There is a short section where they pull out a magazine and show the centrefold. That's about all there is in terms of naughty bits according to my memory. However if I were to dismiss the naughty bit, I'd still be concerned about the suicide bit, some 5 year olds won't take it very well.

Cheers...
Duy-Khang Hoang

[xradman]

Originally Posted by chefboy1

After watching Memento on dvd back in 2002, I immediately thought it'd be a great idea if there was an option to view the movie again, however, each scene in chronological order. I think people would have a better appreciation of how well-made the film was.

You know this was an option on this movie. As I recall, you had to go into the special features and then rearrange the tire changing test in chronological order to find a hidden option to replay the movie in chronological order through seamless branching. Although it made the movie easier to follow, I preferred the original version.