TFDVDEdit 2 Implements “Seamless Branching”

The DVD-Video Specification’s “Holy Grail” feature, is now available for all DVD authoring systems

by TF

"Seamless Branching", or "Seamless multi-story"; is one of the most advanced capabilities of the DVD format. It is used to create "Director's Cuts" of movies, for example, without having to include the same material twice; and alternative versions with extra "buttons on video" like the White Rabbit feature in the Matrix. And the best news is that once all the asset preparation is done, it takes only a few minutes to perform in TFDVDEdit 2!

The technique of seamless branching uses a special type of interleaving, somewhat akin to multi-angle video, where multiple versions of the video are woven together into "angle blocks", and then the bits which "aren't playing" are skipped over during decoding/playback. However it can do far more than that.

Unlike Angle Blocks, Interleaved Blocks used in seamless branching, with multiple video streams interwoven, do not require the separate clips:

• Be of the same duration
• Be encoded to Mpeg 2 with Closed GOPs and have the same GOP structure

With Interleaved Blocks:

• Video, audio, sub pictures, and buttons on video can be completely separate and different from the other streams that make up the same Interleaved Block, unlike with Multi-Angle.
• Each Video stream in the Interleaved Block, can have the full compliment of up to 9 video angles*, 8 audio streams, 32 subtitle streams, separate chapters and even buttons on video; again each different, or not even present in the other streams in the block.
• The remote control angle, subtitle, and audio stream change keys work only within the current assigned playing stream in the block. The remote cannot jump to another segment/clip in the Interleaved Block; except by navigation command (buttons on video).

This feature is available on only the most expensive proprietary DVD authoring systems, until now.

What you can do with this new capability

It's now possible to:

• Offer multiple seamless versions of your show, without doubling, tripling, or even quadrupling the size of your project. The possibilities are endless of what these multiple version can contain.
• Create seamless, 24 bit, true "white rabbit" types of button on video appearances, with branching off points (the jump to new content supporting the show would not be seamless) to hidden content, that show up only if the viewer selects the feature.
• Shorter versions of the show, i.e. highlight reels, can now be made seamless, saving precious disc space.
• Create multiple seamless versions of menu buttons "compositing" into a stream, complete with different transition sound tracks: menu buttons transition into the Track from scene selection menu button activations; but are not seen when the Track plays through.
• Explore the world of Interleaved Blocks for seamless multiple versions of the DVD's motion menus.
• Defeat DVD player out of spec behavior that jumps Stories (left as they are normally) with the remote next key, royally messing with Abstraction layer authoring systems programming.
• Plus many more artistic and practical uses yet to be discovered and applied; as this is the first time the feature is available for most creative authors and producers since the DVD format began.

TFDVDEdit 2 implements the Seamless Multi-Story Feature behind the scenes, there's NO programming or other user intervention; it's automatic!

TFDVDEdit 2 allows this capability with a to-be-patented method of re interleaving the VOB "after the fact", based on “Stories” the author sets up in the Story supporting authoring system (which makes it nice, as the various versions of the show can be simulated non seamlessly, in advance), or the stories can be created in TFDVDEdit 2, if the authoring system used doesn’t support the story feature.

Then, with the click of a mouse in TFDVDEdit 2, after selecting the PGCs (stories) to be affected; the VOB is re interleaved to make the stories seamless. This operation does not effect DVD Studio Pro® or any other authoring systems Abstraction Layer programming for the project in any way; everything is now made seamless, as it should be, with the flick of a switch. Navigation, as authored, stands; just the VOB is rearranged, you might say :-)

How it works, using the above project schematic as an example project.

Description of example Project

This DVD (please see above illustration) has a short logo intro clip that runs into two different duration versions of the opening credits (the first Interleaved Block), then will play into the movie.

After the movie plays along, a single video stream with two audio and two subtitle tracks, will run into a predetermined point which we've planned for a match frame edit of video and audio, to "branch" into three different versions of the movie, each of different duration. This makes up the second Interleaved Block.

All three versions have also been edited (before encoding to Mpeg 2) to match frame the video and audio back into the movie at the point where their duration comes to an end (in the the "Last Part" marker).

The movie plays along till it hits two different versions of our end credits, which make up the third Interleaved Block of the show. The viewer has been given three menu buttons (color coded for the example), which will take them on a soon-to-be seamless, predetermined path through the Interleaved Blocks in the VOB.

Authoring in DVD Studio Pro

DVD Studio Pro 2 is the easiest authoring system made to create Stories in an Mpeg 2 stream; so we'll use it in this example. Basically, the show and all it's scenes will be lined up, end on end, on the NLE timeline and then encoded to Mpeg 2, or, Mpeg 2 sections we've pre edited and encoded (lot's of match frame editing for different joining goes on with this feature, let me tell you!) are arranged right in DVD Studio Pro 2 in the Track.

The show, as I've got it lined up above, has the sections laid out in the Track, back to back, in this order: Show Start/1st Opening credit Version/2nd Opening Credits Version/Movie Start/Alternate Scene 1/Alternate Scene 2/Alternate Scene 3/Last Part of the Movie/1st Ending/2nd Ending and then finally, the Movies End. As it sits, simulating the timeline from beginning to end wouldn't make much sense, but that's all right, at this point.

We'll make 3 Stories to play back the three different versions of the show, so we'll need markers placed, as shown above, to perfectly divide up the various segments.

The first "red Story" is shown above. This is the path that this version of the show will take when the "red" menu button is activated.

The "Blue Story" pathway through the show.

The "Green Story" pathway through the show (remember, this project example is based on the very first illustration at the top of the page).

Building the Project

Once all the authoring is done (not shown are extra markers, which you can place in the segments to be targets of scene menu buttons, if you'd like), and the stories have been previewed with the simulator, or in the Apple DVD Player (non seamlessly) to make sure that's the playback behavior you want for the 3 different versions. Stories on the disc that skip over segments of the VOB, especially on less reflective DVD-Recordables, can take as long as a couple or so seconds to make the jump to the next marker. Don't worry, that's about to be history.

Once you build the project to hard drive, DVD Studio Pro® will create a VOB for this particular Track, with the segments still end to end. Now it's time to open the VIDEO_TS folder in TFDVDEdit 2.

The VOB is broken up into "billions of bits" :-) and rearranged according to DVD Spec, for players to play it back seamlessly. If a DVD player supports playing back multiple video angles (and they all do), then it will play back the Interleaved Block, no problem. Shown above is how the VOB is repacketized.

A feature implemented painlessly

Once in TFDVDEdit 2, shift-select the three PGCs in the Left Pane that are the Stories, and then right click on one of them and simply choose "Interleave". Done.

Rigorous DVD-Video Specification routines will check the entire VOB, and make sure the bit rate is below 7 or 8 mbps (depending on the number of streams in the particular Interleaved Block), and a whole host of verification routines are run. The VOB will then be repacketized; the "joins" will be re multiplexed to add DVD Spec compliant padding of the video/audio at the joins (about a second), and generally a flurry of activity will be going on; as you continue to work on your project with the hundreds of other things you can do with TFDVDEdit 2. The process runs totally in the background, and is protected while you work on your project! You can even import other Menu VOB's and VTS's, etc., while the process is going on (please be sure to download TFDVDEdit 2's Program Overview to get a glimpse of what we've got here).

The TFDVDEdit support site will have more information, and of course be the hot bed for exploring this capability. Beta testing with this new feature is available now for interested program license holders.

If you have questions, please don't hesitate to ask them in the TFDVDEdit Pre-Sales Support Forum.

More info on TFDVDEdit 2's capabilities found on the TFDVDEdit 2 support site

TFDVDEdit was created by Trai Forrester, Larry Applegate, John Brisbin, Ernie Brock and Robin Henson.