Stereo Video Production : Interlace

Scott Lawrence (formerly with Vuzix Corp.)
yorgle@gmail.com

April 2008


Introduction
Hardware
Filming
Interlace
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Interlaced Video

4.0: Table Of Contents

NOTICE: The following directions are out of date. Vuzix Eyewear now support a side-by-side format for 3D which preserves the picture quality much better than the interlaced video explained below. Update the firmware on your AV920 for side-by-side 3D.

4.1: Camera-Native Field Sequential Content

If your camera system or capture process already contains synced left-right video streams then you can skip over this section. You need only to import your footage into your video editor as you normally would.

4.2: Dual Stream Interleaving Of Content

Interleaving content from two camera sources or video streams into a field-sequential result is a two-step process. First, you must sync the two streams with eachother. Second, you must interleave the two fields together. This page of the documentation will describe both.

4.2.1: Downloads

You can download plugins from above or from http://vuzix.com to help convert two video streams into Field Sequential 3D in Final Cut on the Macintosh, or Adobe After Effects on Windows. It will also add the watermark required to enable 3D viewing on the Vuzix AV230 devices. More on the specifics of that later. These directions will go into detail on how to do this process using this plugin.

4.2.2: Dual Stream Sync


Left-Right Sync

First of all, the two video streams need to be synced with each other. If you have a video camera system that produces a single interlaced stereo video stream you can disregard this step of the process.

Syncing of the two clips is the same as it would be for any multi-camera production. When shooting, use a clapper or some other audio/visual tool to generate a cue that is easy to find on both video streams. You can then line up the two clips based on this cue.

4.2.3: Dual Stream Field Interleaving


Applying the Plugin

We generally have the Right eye as the base, and then overlay the Left eye on top of this. The Left eye then gets our plugin applied to it. The plugin will make one of the two fields of the Left eye transparent, so that the Right eye is visible on the alternate field. This plugin will also let you add the watermark so that you can expand your audience to include AV230 owners.

One thing that we've found to be useful is to hook up an AV230 or AV920 as a video monitor from our DV deck. Final Cut will let you display the active footage out a Firewire DV device attached to the editing system. We then create a 3 second slug of black, and apply the watermark to this. Once that clip is played, the AV230 will switch into 3D mode, and you can easily watch your footage in 3D while you edit it.

4.3: Applying The Watermark

The watermark will enable your video content to turn on the 3D mode in Vuzix eywear. It is recommended to be applied to all of your 3D content. This will require no user interactions or menu settings on the user's part to enable the correct 3D mode for your content.

To turn on the watermark, you simply need to select the correct "Encoding" from the plugin, to match the "Fields" settings. For example, if you have left in field 0, then you should set the encoding to be "3-D, Field 0 is left" or "3-D, Field 0 is right", depending on how you've layed out your projcet. This "Field 0" corrolates to the above "Fields" setting, and which eye's video the plugin has been applied to.

We understand that this can be confusing, so if there are any questions at all, feel free to email me directly with your questions. My email address is at the top of this page.

4.3.1: Things to consider...

In some rare cases, the watermark may not be detected by the AV230 device. We suggest that you add the watermark to a 2-3 second black clip at the beginning of your production, or add it to your production's title cards, assuming that there is little to no image complexity in the bottom left corner for those clips.

We recommend using the default settings for the watermark size, contrast and position. In rare cases, you may need to adjust its vertical placement, or its contrast level to make sure that it is detected properly.

You can always render your footage, and view it in realtime to make sure it is detected properly, as described on the "Edit" page of this documentation

Some editing packages, such as Adobe Premiere will silently drop the top and bottom of the video footage if it is larger than 480 lines tall. This happens with D1 footage for example. Note that in these cases, you will need to move the watermark up a few lines.

The default numbers for placement are optimal for 480 line video content. If it is applied to footage that is 496 lines, it will now be 8 lines below its optimal position, and will need to be moved upwards by 8 lines.

4.4: Field Sequential DVD Video Content

First, a disclaimer. Using tools to circumvent a copyright device or copy protection is illegal if you do not own or have proper rights to use the content as such. Consult your local copyright/DMCA laws for further details. For the sake of this documentation, the following will describe how to perform this functionality on media which you properly own or of which you posess the rights.

4.4.1: Complete DVD Copy

This method is the preferred method, especially if you have the available space on your hard disk.

The first step is copying the content of your DVD media to your local hard drive. This will take between 4-8 gigs of storage space on your disk. Use a tool like "MacTheRipper" to copy the files over properly.

Next, open up VisualHub, and drag the .VOB files from the above step's "VIDEO_TS" folder into the list area. Select the "DV" tab, and select "Ready For Final Cut".

Press "Start", and wait for it to complete. The resulting .DV files can now be dropped into Final Cut and edited there.

The downside of this method is that you sometimes will get a glitch at the transition from one ".VOB" to the next. The upshot is that you can exactly recreate the large .DV files from any time, by just following the same process.

4.4.2: DVD Player Capture

An alternate capture method is to play the DVD, "full size" in a window. Now, start up a tool like "SnapZ Pro" or "iShowU", with a capture size of 640x480, and capture the segments of content you need. Be sure to save it as .DV format, to be directly brought into Final Cut.

The downside of this method is that you will be unable to reproduce the video files, and will need to back them up with your project in their entirety. The upshot is that you will only capture the segments you need.


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This page is a part of the Yorgle Notebook.

DISCLAIMER:
This author of this page was happily employed by the Vuzix Corporation. All hacks and modifications are acknowledged but not advised by Vuzix. Do modifications at your own risk. No warranty is expressed or implied. That said, the content described above is known to have worked for me and is correct to the best of my knowledge. Any questions about the content, procedures, or information should be directed to me at the email address given at the top of the page.