How to send video between systems for less than $100

NDI is developed by NewTek and it’s literally magic. It’s so simple to set up because there really isn’t anything to set up…

So what is it?

NDI stands for Network Device Interface and is used to send video, audio, and control over a gigabit network. It allows anything that supports NDI on a network to be a source and an output. So far from my testing, it can do pretty well over wi-fi, but I would recommend everything be hardwired.

Here’s how NewTek describes it:

NDI®, NewTek’s innovative Network Device Interface technology, is a royalty free standard enabling IP video workflows across Ethernet networks. NDI is a bi-directional standard that allows video systems to identify and communicate with one another over IP. Enabling them to encode, transmit, and receive multiple streams of broadcast-quality, low latency, frame-accurate video and audio in real time. The NDI encoding algorithm is resolution and frame rate independent. It supports up to 4K and beyond, as well as multi-channel, floating-point audio up to 16 channels and beyond. NDI also includes tools to implement video access and grouping, bi-directional metadata, tally, and more.

NewTek

This changes everything…

Another really amazing feature is alpha channel support. If you aren’t familiar with what an alpha channel is let me explain. A video signal has Red, Green, and Blue channels that control the color values. It also has a luminance channel that controls the darkness and brightness of different areas in the video. Lastly, there is the alpha channel which controls what parts of the video are transparent or see-through.

This is huge for churches, especially those streaming their services. Why? Because most churches want to overlay song lyrics or sermon notes onto their stream or in house screens. Pro Presenter does have an alpha key module which would allow this but you need expensive hardware and a video switcher that supports an alpha channel to do that. That’s just a crazy expense for most churches.

The other method most switchers support is luma key or chroma key. Meaning you have your words on a black background with white text and the switcher takes out the black. Or a solid color background (usually green or blue) for chroma key. The problem with this method is that in most cases the edges of the text looks terrible because there are leftover artifacts from the black or green color. There’s also no anti-aliasing so it isn’t smooth. This method also doesn’t allow for gradients. No Gradients means you can’t have any nice shadow or outer glow on the text to better separate it from the background video.

With NDI and the Pro Presenter module described below, you can send a Pro Presenter output with no background over the network! With shadows and everything!! (That’s very exciting)



How Pro Presenter 6 integrates with NDI

The free way:

Pro Presenter 6 on OSX has support for a technology called Syphon which allows applications on the mac to share video streams. In this case, the output from Pro Presenter. There is another program called NDISyphon which takes the Syphon output of Pro Presenter and converts it into an NDI stream. Now you can simply select the mac as an NDI source in your switcher and boom! (This method doesn’t support an alpha channel)

This way doesn’t look as nice, there can be digital artifacts which make it look kinda bad. However, I would definitely give it a try though and see how it works for you! I mean its free so there’s nothing to loose.

By the way there’s a great free switcher software called OBS you should check out! It also streams and records which is nice.

The $99 Way:

This way works on Windows and OSX and supports an alpha channel. Just buy the SDI/NDI Module for Pro Presenter. Set your preferences and start broadcasting the output to whatever supports NDI on your network!

How does this work with the Multiscreen Module?

It’s even cooler! The NDI stream’s resolution is two or three screens wide depending on your Matrox device set up.

After more testing, I discovered that the above statement is true for the free way, but the $99 way doesn’t work the same.

Once you purchase the SDI/NDI module you’ll need to head over to your display settings to pick which output you want to send over NDI. Unfortunately, you can only send one. If you are using a Dulahead2go that only has two outputs, you’ll click the left or right arrows shown circled above. For the 1st output click the left arrow and for the 2nd click the right. If you are using a Tripplehead2go you’ll use the left, right, and middle square buttons. Left is output 1, the square is output 2, right is output 3. I will say this way is much higher quality and it supports transparency.

Back to the free way though… In OBS for example all you need to do is scale the Pro Presenter NDI layer so that it matches the height of the scene frame. Then shift it left and right to show the part of the multiscreen output you want to show. The even even cooler part is that you can use the same NDI source multiple times! That means you can have all three of the multiscreen outputs as different layers on the same scene or other scenes.

Ok, this is all cool but I want it to do more.

It does more!! There are PTZ cameras that support ndi natively. (PTZ Stands for Pan Tilt Zoom) With only a single network cable connected to each one of these cameras it gets:

1.) Power (POE) 
2.) Video Signal 
3.) Audio Signal (Which you probably wouldn’t need)
4.) Tally Light (The little red light that shows which camera is live)
5.) Pan, Tilt, and Zoom control

That’s magic!

Check out these two NDI supported cameras, they are both really cool!

Already have a camera you like?

If you already have a camera and would like it to use NDI no problem! This device will covert hdmi or sdi to an NDI stream. It even has a red bar that lights up when the camera is the source currently being used by your switcher hardware or software (It’s called a Tally Light). That can help your subject know which camera to look at.

Let me know what you think!

Please comment below if you have any questions. I’m pretty excited about this so there might be some info left out. If you’ve used NDI and I was totally wrong about something let me know. Got any tips?

Also if you wouldn’t mind, hit me up on our social pages! Thanks!

Austin Thomas

Austin Thomas

Austin has been doing audiovisual work in churches for well over 10 years. He is experienced in all aspects of production, from live events to producing engaging content. You can see some of his work at austinparrishthomas.com

2 Responses

Add a Comment

Your email address will not be published. Required fields are marked *