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VidBlaster Showcase: Remote sign language interpretation in live video productions

Wednesday, 30 November 2011

With just the right setting and a bit of training, you can use Vidblaster to be a complete Remote sign language interpretation video production set. Using VidBlaster to superimpose a sign interpreter on a video in live situations is basically very straight forward. Just take the original video stream, shrink it to a Picture-in-Picture (PiP) on a background image, get your sign interpreter positioned properly on the screen, and key in the sign interpreter over the PiP composition. You may do this offline with a pre-recorded video, or online by grabbing a live video stream from a camera or remote location. The result can be delivered  in realtime over internet as a separate live video stream. For this kind of production all you need is a decent Windows PC, at least VidBlaster Pro, a camera, something that works as a green screen, a few lamps, a small sound mixer, and of course an internet connection if you want to do it online. 

Five steps from original to signed interpreted video

In theory there are five steps that take you from any original video to a nice sign interpreted live video. The steps are outlined here, together with an example that illustrates how it might look like in VidBlaster. In practice you may need fewer or more steps, depending on your previous experiences and current ambition.


VidBlaster Showcase: Remote sign language interpretation in live video productions

A: Decide on how to get the original video

There are three different types of sources for the original video. The first one is video from a cable attached to a local camera. The second alternative is any video played on the production PC running VidBlaster. This type include videos displayed in a web browser, such as those from YouTube or TED/talks. Finally, our third type is the so called RTSP/RTMP stream, a livestream send from another streaming source or service (e.g. Bambuser).

B: Make room in the picture for the sign interpreter

To avoid the sign interpreter is obscuring too much of the image in the original video, we need to create some empty space. How much, and where, is a balance between the need of the viewers and your artistic ambitions.

C: Position the sign interpreter in the screen

The chromakey effect works by combining two full screen images. So, either you have to put the sign interpreter in front of a huge green screen, properly scaled and positioned in the eye of the camera. Or, as in our example, you use another video effect to obtain the same result. Hence, “Video Effect 2” is used here to scale and position the sign interpreter on the video screen.

D: Superimpose the sign interpreter with chroma key

The next step is pretty straight forward. “Video Effect 3” is set to use Chroma Key and combine the output from “Video Effect 1” (shrunken original) with the output from “Video Effect 2” (positioned interpreter on green background). The module’s “auto-key” option will be sufficient to give you a nice result with few artifacts. If needed, you can adjust the chroma key settings manually.

E: Stream and record

VidBlaster is capable of streaming directly to multiple streaming service providers and record the final result to a movie clip.

More information

Visit the VidBlaster Wiki to see all details and example videos from this Remote sign language interpretation implementation or see other usages of VidBlaster.

Feel free to discuss this article on the VidBlaster Forum.